summaryrefslogtreecommitdiffstats
path: root/doc/lua-api/index.rst
blob: e8df63e02a6cf3a43f7dc768ba7b5a5808347310 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
3583
3584
3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
3595
3596
3597
3598
3599
3600
3601
3602
3603
3604
3605
3606
3607
3608
3609
3610
3611
3612
3613
3614
3615
3616
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642
3643
3644
3645
3646
3647
3648
3649
3650
3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3678
3679
3680
3681
3682
3683
3684
3685
3686
3687
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
3713
3714
3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
3725
3726
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
3758
3759
3760
3761
3762
3763
3764
3765
3766
3767
3768
3769
3770
3771
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789
3790
3791
3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
3846
3847
3848
3849
3850
3851
3852
3853
3854
3855
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
3866
3867
3868
3869
3870
3871
3872
3873
3874
3875
3876
3877
3878
3879
3880
3881
3882
3883
3884
3885
3886
3887
3888
3889
3890
3891
3892
3893
3894
3895
3896
3897
3898
3899
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
3917
3918
3919
3920
3921
3922
3923
3924
3925
3926
3927
3928
3929
3930
3931
3932
3933
3934
3935
3936
3937
3938
3939
3940
3941
3942
3943
3944
3945
3946
3947
3948
3949
3950
3951
3952
3953
3954
3955
3956
3957
3958
3959
3960
3961
3962
3963
3964
3965
3966
3967
3968
3969
3970
3971
3972
3973
3974
3975
3976
3977
3978
3979
3980
3981
3982
3983
3984
3985
3986
3987
3988
3989
3990
3991
3992
3993
3994
3995
3996
3997
3998
3999
4000
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
4025
4026
4027
4028
4029
4030
4031
4032
4033
4034
4035
4036
4037
4038
4039
4040
4041
4042
4043
4044
4045
4046
4047
4048
4049
4050
4051
4052
4053
4054
4055
4056
4057
4058
4059
4060
4061
4062
4063
4064
4065
4066
4067
4068
4069
4070
4071
4072
4073
4074
4075
4076
4077
4078
4079
4080
4081
4082
4083
4084
4085
4086
4087
4088
4089
4090
4091
4092
4093
4094
4095
4096
4097
4098
4099
4100
4101
4102
4103
4104
4105
4106
4107
4108
4109
4110
4111
4112
4113
4114
4115
4116
4117
4118
4119
4120
4121
4122
4123
4124
4125
4126
4127
4128
4129
4130
4131
4132
4133
4134
4135
4136
4137
4138
4139
4140
4141
4142
4143
4144
4145
4146
4147
4148
4149
4150
4151
4152
4153
4154
4155
4156
4157
4158
4159
4160
4161
4162
4163
4164
4165
4166
4167
4168
4169
4170
4171
4172
4173
4174
4175
4176
4177
4178
4179
4180
4181
4182
4183
4184
4185
4186
4187
4188
4189
4190
4191
4192
4193
4194
4195
4196
4197
4198
4199
4200
4201
4202
4203
4204
4205
4206
4207
4208
4209
4210
4211
4212
4213
4214
4215
4216
4217
4218
4219
4220
4221
4222
4223
4224
4225
4226
4227
4228
4229
4230
4231
4232
4233
4234
4235
4236
4237
4238
4239
4240
4241
4242
4243
4244
4245
4246
4247
4248
4249
4250
4251
4252
4253
4254
4255
4256
4257
4258
4259
4260
4261
4262
4263
4264
4265
4266
4267
4268
4269
4270
4271
4272
4273
4274
4275
4276
4277
4278
4279
4280
4281
4282
4283
4284
4285
4286
4287
4288
4289
4290
4291
4292
4293
4294
4295
4296
4297
4298
4299
4300
4301
4302
4303
4304
4305
4306
4307
4308
4309
4310
4311
4312
4313
4314
4315
4316
4317
4318
4319
4320
4321
4322
4323
4324
4325
4326
4327
4328
4329
4330
4331
4332
4333
4334
4335
4336
4337
4338
4339
4340
4341
4342
4343
4344
4345
4346
4347
4348
4349
4350
4351
4352
4353
4354
4355
4356
4357
4358
4359
4360
4361
4362
4363
4364
4365
4366
4367
4368
4369
4370
4371
4372
4373
4374
4375
4376
4377
4378
4379
4380
4381
4382
4383
4384
4385
4386
4387
4388
4389
4390
4391
4392
4393
4394
4395
4396
4397
4398
4399
4400
4401
4402
4403
4404
4405
4406
4407
4408
4409
4410
4411
4412
4413
4414
4415
4416
4417
4418
4419
4420
4421
4422
4423
4424
4425
4426
4427
4428
4429
4430
4431
4432
4433
4434
4435
4436
4437
4438
4439
4440
4441
4442
4443
4444
4445
4446
4447
4448
4449
4450
4451
4452
4453
4454
4455
4456
4457
4458
4459
4460
4461
4462
4463
4464
4465
4466
4467
4468
4469
4470
4471
4472
4473
4474
4475
4476
4477
4478
4479
4480
4481
4482
4483
4484
4485
4486
4487
4488
4489
4490
4491
.. toctree::
   :maxdepth: 2


How Lua runs in HAProxy
=======================

HAProxy Lua running contexts
----------------------------

The Lua code executed in HAProxy can be processed in 2 main modes. The first one
is the **initialisation mode**, and the second is the **runtime mode**.

* In the **initialisation mode**, we can perform DNS solves, but we cannot
  perform socket I/O. In this initialisation mode, HAProxy still blocked during
  the execution of the Lua program.

* In the **runtime mode**, we cannot perform DNS solves, but we can use sockets.
  The execution of the Lua code is multiplexed with the requests processing, so
  the Lua code seems to be run in blocking, but it is not the case.

The Lua code is loaded in one or more files. These files contains main code and
functions. Lua has 8 execution contexts.

1. The Lua file **body context**. It is executed during the load of the Lua file
   in the HAProxy `[global]` section with the directive `lua-load`. It is
   executed in initialisation mode. This section is use for configuring Lua
   bindings in HAProxy.

2. The Lua **init context**. It is a Lua function executed just after the
   HAProxy configuration parsing. The execution is in initialisation mode. In
   this context the HAProxy environment are already initialized. It is useful to
   check configuration, or initializing socket connections or tasks. These
   functions are declared in the body context with the Lua function
   `core.register_init()`. The prototype of the function is a simple function
   without return value and without parameters, like this: `function fcn()`.

3. The Lua **task context**. It is a Lua function executed after the start
   of the HAProxy scheduler, and just after the declaration of the task with the
   Lua function `core.register_task()`. This context can be concurrent with the
   traffic processing. It is executed in runtime mode. The prototype of the
   function is a simple function without return value and without parameters,
   like this: `function fcn()`.

4. The **action context**. It is a Lua function conditionally executed. These
   actions are registered by the Lua directives "`core.register_action()`". The
   prototype of the Lua called function is a function with doesn't returns
   anything and that take an object of class TXN as entry. `function fcn(txn)`.

5. The **sample-fetch context**. This function takes a TXN object as entry
   argument and returns a string. These types of function cannot execute any
   blocking function. They are useful to aggregate some of original HAProxy
   sample-fetches and return the result. The prototype of the function is
   `function string fcn(txn)`. These functions can be registered with the Lua
   function `core.register_fetches()`. Each declared sample-fetch is prefixed by
   the string "lua.".

   .. note::
      It is possible that this function cannot found the required data in the
      original HAProxy sample-fetches, in this case, it cannot return the
      result. This case is not yet supported

6. The **converter context**. It is a Lua function that takes a string as input
   and returns another string as output. These types of function are stateless,
   it cannot access to any context. They don't execute any blocking function.
   The call prototype is `function string fcn(string)`. This function can be
   registered with the Lua function `core.register_converters()`. Each declared
   converter is prefixed by the string "lua.".

7. The **filter context**: It is a Lua object based on a class defining filter
   callback functions. Lua filters are registered using
   `core.register_filter()`. Each declared filter is prefixed by the string
   "lua.".

8. The **event context**: Inside a function that handles events subscribed
   through `core.event_sub()` or `Server.event_sub()`.


HAProxy Lua Hello world
-----------------------

HAProxy configuration file (`hello_world.conf`):

::

    global
       lua-load hello_world.lua

    listen proxy
       bind 127.0.0.1:10001
       tcp-request inspect-delay 1s
       tcp-request content use-service lua.hello_world

HAProxy Lua file (`hello_world.lua`):

.. code-block:: lua

    core.register_service("hello_world", "tcp", function(applet)
       applet:send("hello world\n")
    end)

How to start HAProxy for testing this configuration:

::

    ./haproxy -f hello_world.conf

On other terminal, you can test with telnet:

::

    #:~ telnet 127.0.0.1 10001
    hello world

Usage of load parameters
------------------------

HAProxy lua-load(-per-thread) directives allow a list of parameters after
the lua file name. These parameters are accessible through an array of args
using this code `local args = table.pack(...)` in the body of loaded file.

Below, a new version of the hello world using load parameters

HAProxy configuration file (`hello_world.conf`):

::

    global
       lua-load hello_world.lua "this is not an hello world"

    listen proxy
       bind 127.0.0.1:10001
       tcp-request inspect-delay 1s
       tcp-request content use-service lua.hello_world

HAProxy Lua file (`hello_world.lua`):

.. code-block:: lua

    local args = table.pack(...)

    core.register_service("hello_world", "tcp", function(applet)
       applet:send(args[1] .. "\n")
    end)


Core class
==========

.. js:class:: core

   The "core" class contains all the HAProxy core functions. These function are
   useful for the controlling of the execution flow, registering hooks,
   manipulating global maps or ACL, ...

   "core" class is basically provided with HAProxy. No `require` line is
   required to uses these function.

   The "core" class is static, it is not possible to create a new object of this
   type.

.. js:attribute:: core.emerg

  :returns: integer

  This attribute is an integer, it contains the value of the loglevel
  "emergency" (0).

.. js:attribute:: core.alert

  :returns: integer

  This attribute is an integer, it contains the value of the loglevel
  "alert" (1).

.. js:attribute:: core.crit

  :returns: integer

  This attribute is an integer, it contains the value of the loglevel
  "critical" (2).

.. js:attribute:: core.err

  :returns: integer

  This attribute is an integer, it contains the value of the loglevel
  "error" (3).

.. js:attribute:: core.warning

  :returns: integer

  This attribute is an integer, it contains the value of the loglevel
  "warning" (4).

.. js:attribute:: core.notice

  :returns: integer

  This attribute is an integer, it contains the value of the loglevel
  "notice" (5).

.. js:attribute:: core.info

  :returns: integer

  This attribute is an integer, it contains the value of the loglevel
  "info" (6).

.. js:attribute:: core.debug

  :returns: integer

  This attribute is an integer, it contains the value of the loglevel
  "debug" (7).

.. js:attribute:: core.proxies

  **context**: init, task, action, sample-fetch, converter

  This attribute is a table of declared proxies (frontend and backends). Each
  proxy give an access to his list of listeners and servers. The table is
  indexed by proxy name, and each entry is of type :ref:`proxy_class`.

  .. Warning::
     if you declared a frontend and backend with the same name, only one of
     them will be listed.

  :see: :js:attr:`core.backends`
  :see: :js:attr:`core.frontends`

.. js:attribute:: core.backends

  **context**: init, task, action, sample-fetch, converter

  This attribute is a table of declared proxies with backend capability. Each
  proxy give an access to his list of listeners and servers. The table is
  indexed by the backend name, and each entry is of type :ref:`proxy_class`.

  :see: :js:attr:`core.proxies`
  :see: :js:attr:`core.frontends`

.. js:attribute:: core.frontends

  **context**: init, task, action, sample-fetch, converter

  This attribute is a table of declared proxies with frontend capability. Each
  proxy give an access to his list of listeners and servers. The table is
  indexed by the frontend name, and each entry is of type :ref:`proxy_class`.

  :see: :js:attr:`core.proxies`
  :see: :js:attr:`core.backends`

.. js:attribute:: core.thread

  **context**: task, action, sample-fetch, converter, applet

  This variable contains the executing thread number starting at 1. 0 is a
  special case for the common lua context. So, if thread is 0, Lua scope is
  shared by all threads, otherwise the scope is dedicated to a single thread.
  A program which needs to execute some parts exactly once regardless of the
  number of threads can check that core.thread is 0 or 1.

.. js:function:: core.log(loglevel, msg)

  **context**: body, init, task, action, sample-fetch, converter

  This function sends a log. The log is sent, according with the HAProxy
  configuration file, to the loggers relevant to the current context and/or
  to stderr if it is allowed.

  The exact behaviour depends on tune.lua.log.loggers and tune.lua.log.stderr.

  :param integer loglevel: Is the log level associated with the message. It is a
   number between 0 and 7.
  :param string msg: The log content.
  :see: :js:attr:`core.emerg`, :js:attr:`core.alert`, :js:attr:`core.crit`,
    :js:attr:`core.err`, :js:attr:`core.warning`, :js:attr:`core.notice`,
    :js:attr:`core.info`, :js:attr:`core.debug` (log level definitions)
  :see: :js:func:`core.Debug`
  :see: :js:func:`core.Info`
  :see: :js:func:`core.Warning`
  :see: :js:func:`core.Alert`

.. js:function:: core.Debug(msg)

  **context**: body, init, task, action, sample-fetch, converter

  :param string msg: The log content.
  :see: :js:func:`core.log`

  Does the same job than:

.. code-block:: lua

  function Debug(msg)
    core.log(core.debug, msg)
  end
..

.. js:function:: core.Info(msg)

  **context**: body, init, task, action, sample-fetch, converter

  :param string msg: The log content.
  :see: :js:func:`core.log`

.. code-block:: lua

  function Info(msg)
    core.log(core.info, msg)
  end
..

.. js:function:: core.Warning(msg)

  **context**: body, init, task, action, sample-fetch, converter

  :param string msg: The log content.
  :see: :js:func:`core.log`

.. code-block:: lua

  function Warning(msg)
    core.log(core.warning, msg)
  end
..

.. js:function:: core.Alert(msg)

  **context**: body, init, task, action, sample-fetch, converter

  :param string msg: The log content.
  :see: :js:func:`core.log`

.. code-block:: lua

  function Alert(msg)
    core.log(core.alert, msg)
  end
..

.. js:function:: core.add_acl(filename, key)

  **context**: init, task, action, sample-fetch, converter

  Add the ACL *key* in the ACLs list referenced by the file *filename*.

  :param string filename: the filename that reference the ACL entries.
  :param string key: the key which will be added.

.. js:function:: core.del_acl(filename, key)

  **context**: init, task, action, sample-fetch, converter

  Delete the ACL entry referenced by the key *key* in the list of ACLs
  referenced by *filename*.

  :param string filename: the filename that reference the ACL entries.
  :param string key: the key which will be deleted.

.. js:function:: core.del_map(filename, key)

  **context**: init, task, action, sample-fetch, converter

  Delete the map entry indexed with the specified key in the list of maps
  referenced by his filename.

  :param string filename: the filename that reference the map entries.
  :param string key: the key which will be deleted.

.. js:function:: core.get_info()

  **context**: body, init, task, action, sample-fetch, converter

  Returns HAProxy core information. We can find information like the uptime,
  the pid, memory pool usage, tasks number, ...

  This information is also returned by the management socket via the command
  "show info". See the management socket documentation for more information
  about the content of these variables.

  :returns: an array of values.

.. js:function:: core.get_var()

  **context**: body, init, task, action, sample-fetch, converter

  Returns data stored in the variable <var> converter in Lua type.
  This is limited to "proc." scoped variables.

  :param string var: The variable name in "proc." scope according with the
   HAProxy variable syntax.

.. js:function:: core.now()

  **context**: body, init, task, action

  This function returns the current time. The time returned is fixed by the
  HAProxy core and assures than the hour will be monotonic and that the system
  call 'gettimeofday' will not be called too. The time is refreshed between each
  Lua execution or resume, so two consecutive call to the function "now" will
  probably returns the same result.

  :returns: a table which contains two entries "sec" and "usec". "sec"
   contains the current at the epoch format, and "usec" contains the
   current microseconds.

.. js:function:: core.http_date(date)

  **context**: body, init, task, action

  This function take a string representing http date, and returns an integer
  containing the corresponding date with a epoch format. A valid http date
  me respect the format IMF, RFC850 or ASCTIME.

  :param string date: a date http-date formatted
  :returns: integer containing epoch date
  :see: :js:func:`core.imf_date`.
  :see: :js:func:`core.rfc850_date`.
  :see: :js:func:`core.asctime_date`.
  :see: https://tools.ietf.org/html/rfc7231#section-7.1.1.1

.. js:function:: core.imf_date(date)

  **context**: body, init, task, action

  This function take a string representing IMF date, and returns an integer
  containing the corresponding date with a epoch format.

  :param string date: a date IMF formatted
  :returns: integer containing epoch date
  :see: https://tools.ietf.org/html/rfc7231#section-7.1.1.1

  The IMF format is like this:

.. code-block:: text

	Sun, 06 Nov 1994 08:49:37 GMT
..

.. js:function:: core.rfc850_date(date)

  **context**: body, init, task, action

  This function take a string representing RFC850 date, and returns an integer
  containing the corresponding date with a epoch format.

  :param string date: a date RFC859 formatted
  :returns: integer containing epoch date
  :see: https://tools.ietf.org/html/rfc7231#section-7.1.1.1

  The RFC850 format is like this:

.. code-block:: text

	Sunday, 06-Nov-94 08:49:37 GMT
..

.. js:function:: core.asctime_date(date)

  **context**: body, init, task, action

  This function take a string representing ASCTIME date, and returns an integer
  containing the corresponding date with a epoch format.

  :param string date: a date ASCTIME formatted
  :returns: integer containing epoch date
  :see: https://tools.ietf.org/html/rfc7231#section-7.1.1.1

  The ASCTIME format is like this:

.. code-block:: text

	Sun Nov  6 08:49:37 1994
..

.. js:function:: core.msleep(milliseconds)

  **context**: body, init, task, action

  The `core.msleep()` stops the Lua execution between specified milliseconds.

  :param integer milliseconds: the required milliseconds.

.. js:function:: core.register_action(name, actions, func [, nb_args])

  **context**: body

  Register a Lua function executed as action. All the registered action can be
  used in HAProxy with the prefix "lua.". An action gets a TXN object class as
  input.

  :param string name: is the name of the action.
  :param table actions: is a table of string describing the HAProxy actions
   facilities where to expose the new action. Expected facilities  are:
   'tcp-req', 'tcp-res', 'http-req', 'http-res', 'http-after-res'.
  :param function func: is the Lua function called to work as an action.
  :param integer nb_args: is the expected number of argument for the action.
   By default the value is 0.

  The prototype of the Lua function used as argument is:

.. code-block:: lua

  function(txn [, arg1 [, arg2]])
..

  * **txn** (:ref:`txn_class`): this is a TXN object used for manipulating the
            current request or TCP stream.

  * **argX**: this is argument provided through the HAProxy configuration file.

  Here, an example of action registration. The action just send an 'Hello world'
  in the logs.

.. code-block:: lua

  core.register_action("hello-world", { "tcp-req", "http-req" }, function(txn)
     txn:Info("Hello world")
  end)
..

  This example code is used in HAProxy configuration like this:

::

  frontend tcp_frt
    mode tcp
    tcp-request content lua.hello-world

  frontend http_frt
    mode http
    http-request lua.hello-world

..

  A second example using arguments

.. code-block:: lua

  function hello_world(txn, arg)
     txn:Info("Hello world for " .. arg)
  end
  core.register_action("hello-world", { "tcp-req", "http-req" }, hello_world, 2)

..

  This example code is used in HAProxy configuration like this:

::

  frontend tcp_frt
    mode tcp
    tcp-request content lua.hello-world everybody

..

.. js:function:: core.register_converters(name, func)

  **context**: body

  Register a Lua function executed as converter. All the registered converters
  can be used in HAProxy with the prefix "lua.". A converter gets a string as
  input and returns a string as output. The registered function can take up to 9
  values as parameter. All the values are strings.

  :param string name: is the name of the converter.
  :param function func: is the Lua function called to work as converter.

  The prototype of the Lua function used as argument is:

.. code-block:: lua

  function(str, [p1 [, p2 [, ... [, p5]]]])
..

  * **str** (*string*): this is the input value automatically converted in
    string.
  * **p1** .. **p5** (*string*): this is a list of string arguments declared in
    the HAProxy configuration file. The number of arguments doesn't exceed 5.
    The order and the nature of these is conventionally chosen by the
    developer.

.. js:function:: core.register_fetches(name, func)

  **context**: body

  Register a Lua function executed as sample fetch. All the registered sample
  fetch can be used in HAProxy with the prefix "lua.". A Lua sample fetch
  returns a string as output. The registered function can take up to 9 values as
  parameter. All the values are strings.

  :param string name: is the name of the sample fetch.
  :param function func: is the Lua function called to work as sample fetch.

  The prototype of the Lua function used as argument is:

.. code-block:: lua

    string function(txn, [p1 [, p2 [, ... [, p5]]]])
..

  * **txn** (:ref:`txn_class`): this is the txn object associated with the
    current request.
  * **p1** .. **p5** (*string*): this is a list of string arguments declared in
    the HAProxy configuration file. The number of arguments doesn't exceed 5.
    The order and the nature of these is conventionally chosen by the
    developer.
  * **Returns**: A string containing some data, or nil if the value cannot be
    returned now.

  lua example code:

.. code-block:: lua

    core.register_fetches("hello", function(txn)
        return "hello"
    end)
..

  HAProxy example configuration:

::

    frontend example
       http-request redirect location /%[lua.hello]

.. js:function:: core.register_filter(name, Flt, func)

  **context**: body

  Register a Lua function used to declare a filter. All the registered filters
  can by used in HAProxy with the prefix "lua.".

  :param string name: is the name of the filter.
  :param table Flt: is a Lua class containing the filter definition (id, flags,
   callbacks).
  :param function func: is the Lua function called to create the Lua filter.

  The prototype of the Lua function used as argument is:

.. code-block:: lua

  function(flt, args)
..

  * **flt** : Is a filter object based on the class provided in
    :js:func:`core.register_filter()` function.

  * **args**: Is a table of strings containing all arguments provided through
    the HAProxy configuration file, on the filter line.

  It must return the filter to use or nil to ignore it. Here, an example of
  filter registration.

.. code-block:: lua

  core.register_filter("my-filter", MyFilter, function(flt, args)
     flt.args = args -- Save arguments
     return flt
  end)
..

  This example code is used in HAProxy configuration like this:

::

  frontend http
    mode http
    filter lua.my-filter arg1 arg2 arg3

..

  :see: :js:class:`Filter`

.. js:function:: core.register_service(name, mode, func)

  **context**: body

  Register a Lua function executed as a service. All the registered services
  can be used in HAProxy with the prefix "lua.". A service gets an object class
  as input according with the required mode.

  :param string name: is the name of the service.
  :param string mode: is string describing the required mode. Only 'tcp' or
   'http' are allowed.
  :param function func: is the Lua function called to work as service.

  The prototype of the Lua function used as argument is:

.. code-block:: lua

  function(applet)
..

  * **applet** *applet*  will be a :ref:`applettcp_class` or a
    :ref:`applethttp_class`. It depends the type of registered applet. An applet
    registered with the 'http' value for the *mode* parameter will gets a
    :ref:`applethttp_class`. If the *mode* value is 'tcp', the applet will gets
    a :ref:`applettcp_class`.

  .. warning::
     Applets of type 'http' cannot be called from 'tcp-*' rulesets. Only the
     'http-*' rulesets are authorized, this means that is not possible to call
     a HTTP applet from a proxy in tcp mode. Applets of type 'tcp' can be
     called from anywhere.

  Here, an example of service registration. The service just send an
  'Hello world' as an http response.

.. code-block:: lua

  core.register_service("hello-world", "http", function(applet)
     local response = "Hello World !"
     applet:set_status(200)
     applet:add_header("content-length", string.len(response))
     applet:add_header("content-type", "text/plain")
     applet:start_response()
     applet:send(response)
  end)
..

  This example code is used in HAProxy configuration like this:

::

    frontend example
       http-request use-service lua.hello-world

.. js:function:: core.register_init(func)

  **context**: body

  Register a function executed after the configuration parsing. This is useful
  to check any parameters.

  :param function func: is the Lua function called to work as initializer.

  The prototype of the Lua function used as argument is:

.. code-block:: lua

    function()
..

  It takes no input, and no output is expected.

.. js:function:: core.register_task(func[, arg1[, arg2[, ...[, arg4]]]])

  **context**: body, init, task, action, sample-fetch, converter, event

  Register and start independent task. The task is started when the HAProxy
  main scheduler starts. For example this type of tasks can be executed to
  perform complex health checks.

  :param function func: is the Lua function called to work as an async task.

  Up to 4 optional arguments (all types supported) may be passed to the
  function. (They will be passed as-is to the task function)

  The prototype of the Lua function used as argument is:

.. code-block:: lua

    function([arg1[, arg2[, ...[, arg4]]]])
..

  It takes up to 4 optional arguments (provided when registering), and no
  output is expected.

  See also :js:func:`core.queue` to dynamically pass data between main context
  and tasks or even between tasks.

.. js:function:: core.register_cli([path], usage, func)

  **context**: body

  Register a custom cli that will be available from haproxy stats socket.

  :param array path: is the sequence of word for which the cli execute the Lua
   binding.
  :param string usage: is the usage message displayed in the help.
  :param function func: is the Lua function called to handle the CLI commands.

  The prototype of the Lua function used as argument is:

.. code-block:: lua

    function(AppletTCP, [arg1, [arg2, [...]]])
..

  I/O are managed with the :ref:`applettcp_class` object. Args are given as
  parameter. The args embed the registered path. If the path is declared like
  this:

.. code-block:: lua

    core.register_cli({"show", "ssl", "stats"}, "Display SSL stats..", function(applet, arg1, arg2, arg3, arg4, arg5)
	 end)
..

  And we execute this in the prompt:

.. code-block:: text

    > prompt
    > show ssl stats all
..

  Then, arg1, arg2 and arg3 will contains respectively "show", "ssl" and
  "stats".
  arg4 will contain "all". arg5 contains nil.

.. js:function:: core.set_nice(nice)

  **context**: task, action, sample-fetch, converter

  Change the nice of the current task or current session.

  :param integer nice: the nice value, it must be between -1024 and 1024.

.. js:function:: core.set_map(filename, key, value)

  **context**: init, task, action, sample-fetch, converter

  Set the value *value* associated to the key *key* in the map referenced by
  *filename*.

  :param string filename: the Map reference
  :param string key: the key to set or replace
  :param string value: the associated value

.. js:function:: core.sleep(int seconds)

  **context**: body, init, task, action

  The `core.sleep()` functions stop the Lua execution between specified seconds.

  :param integer seconds: the required seconds.

.. js:function:: core.tcp()

  **context**: init, task, action

  This function returns a new object of a *socket* class.

  :returns: A :ref:`socket_class` object.

.. js:function:: core.httpclient()

  **context**: init, task, action

  This function returns a new object of a *httpclient* class.

  :returns: A :ref:`httpclient_class` object.

.. js:function:: core.concat()

  **context**: body, init, task, action, sample-fetch, converter

  This function returns a new concat object.

  :returns: A :ref:`concat_class` object.

.. js:function:: core.queue()

  **context**: body, init, task, event, action, sample-fetch, converter

  This function returns a new queue object.

  :returns: A :ref:`queue_class` object.

.. js:function:: core.done(data)

  **context**: body, init, task, action, sample-fetch, converter

  :param any data: Return some data for the caller. It is useful with
   sample-fetches and sample-converters.

  Immediately stops the current Lua execution and returns to the caller which
  may be a sample fetch, a converter or an action and returns the specified
  value (ignored for actions and init). It is used when the LUA process finishes
  its work and wants to give back the control to HAProxy without executing the
  remaining code. It can be seen as a multi-level "return".

.. js:function:: core.yield()

  **context**: task, action, sample-fetch, converter

  Give back the hand at the HAProxy scheduler. It is used when the LUA
  processing consumes a lot of processing time.

.. js:function:: core.parse_addr(address)

  **context**: body, init, task, action, sample-fetch, converter

  :param network: is a string describing an ipv4 or ipv6 address and optionally
   its network length, like this: "127.0.0.1/8" or "aaaa::1234/32".
  :returns: a userdata containing network or nil if an error occurs.

  Parse ipv4 or ipv6 addresses and its facultative associated network.

.. js:function:: core.match_addr(addr1, addr2)

  **context**: body, init, task, action, sample-fetch, converter

  :param addr1: is an address created with "core.parse_addr".
  :param addr2: is an address created with "core.parse_addr".
  :returns: boolean, true if the network of the addresses match, else returns
   false.

  Match two networks. For example "127.0.0.1/32" matches "127.0.0.0/8". The
  order of network is not important.

.. js:function:: core.tokenize(str, separators [, noblank])

  **context**: body, init, task, action, sample-fetch, converter

  This function is useful for tokenizing an entry, or splitting some messages.
  :param string str: The string which will be split.
  :param string separators: A string containing a list of separators.
  :param boolean noblank: Ignore empty entries.
  :returns: an array of string.

  For example:

.. code-block:: lua

	local array = core.tokenize("This function is useful, for tokenizing an entry.", "., ", true)
	print_r(array)
..

  Returns this array:

.. code-block:: text

	(table) table: 0x21c01e0 [
	    1: (string) "This"
	    2: (string) "function"
	    3: (string) "is"
	    4: (string) "useful"
	    5: (string) "for"
	    6: (string) "tokenizing"
	    7: (string) "an"
	    8: (string) "entry"
	]
..

.. js:function:: core.event_sub(event_types, func)

  **context**: body, init, task, action, sample-fetch, converter

  Register a function that will be called on specific system events.

  :param array event_types: array of string containing the event types you want
   to subscribe to
  :param function func: is the Lua function called when one of the subscribed
   events occur.
  :returns: A :ref:`event_sub_class` object.
  :see: :js:func:`Server.event_sub()`.

  List of available event types :

   **SERVER** Family:

    * **SERVER_ADD**: when a server is added
    * **SERVER_DEL**: when a server is removed
    * **SERVER_DOWN**: when a server state goes from UP to DOWN
    * **SERVER_UP**: when a server state goes from DOWN to UP
    * **SERVER_STATE**: when a server state changes
    * **SERVER_ADMIN**: when a server administrative state changes
    * **SERVER_CHECK**: when a server's check status change is reported.
      Be careful when subscribing to this type since many events might be
      generated.

   .. Note::
     Use **SERVER** in **event_types** to subscribe to all server events types
     at once. Note that this should only be used for testing purposes since a
     single event source could result in multiple events types being generated.
     (e.g.: SERVER_STATE will always be generated for each SERVER_DOWN or
     SERVER_UP)

  The prototype of the Lua function used as argument is:

.. code-block:: lua

    function(event, event_data, sub, when)
..

  * **event** (*string*): the event type (one of the **event_types** specified
    when subscribing)
  * **event_data**: specific to each event family (For **SERVER** family,
    a :ref:`server_event_class` object)
  * **sub**: class to manage the subscription from within the event
    (a :ref:`event_sub_class` object)
  * **when**: timestamp corresponding to the date when the event was generated.
    It is an integer representing the number of seconds elapsed since Epoch.
    It may be provided as optional argument to `os.date()` lua function to
    convert it to a string according to a given format string.

  .. Warning::
    The callback function will only be scheduled on the very same thread that
    performed the subscription.

    Moreover, each thread treats events sequentially. It means that if you
    have, let's say SERVER_UP followed by a SERVER_DOWN in a short timelapse,
    then the cb function will first be called with SERVER_UP, and once it's
    done handling the event, the cb function will be called again with
    SERVER_DOWN.

    This is to ensure event consistency when it comes to logging / triggering
    logic from lua.

    Your lua cb function may yield if needed, but you're pleased to process the
    event as fast as possible to prevent the event queue from growing up,
    depending on the event flow that is expected for the given subscription.

    To prevent abuses, if the event queue for the current subscription goes
    over a certain amount of unconsumed events, the subscription will pause
    itself automatically for as long as it takes for your handler to catch up.
    This would lead to events being missed, so an error will be reported in the
    logs to warn you about that.
    This is not something you want to let happen too often, it may indicate
    that you subscribed to an event that is occurring too frequently or/and
    that your callback function is too slow to keep up the pace and you should
    review it.

    If you want to do some parallel processing because your callback functions
    are slow: you might want to create subtasks from lua using
    :js:func:`core.register_task()` from within your callback function to
    perform the heavy job in a dedicated task and allow remaining events to be
    processed more quickly.

.. js:function:: core.disable_legacy_mailers()

  **LEGACY**

  **context**: body, init

  Disable the sending of email alerts through the legacy email sending
  function when mailers are used in the configuration.

  Use this when sending email alerts directly from lua.

  :see: :js:func:`Proxy.get_mailers()`

.. _proxy_class:

Proxy class
============

.. js:class:: Proxy

  This class provides a way for manipulating proxy and retrieving information
  like statistics.

.. js:attribute:: Proxy.name

  Contain the name of the proxy.

  .. warning::
     This attribute is now deprecated and will eventually be removed.
     Please use :js:func:`Proxy.get_name()` function instead.

.. js:function:: Proxy.get_name()

  Returns the name of the proxy.

.. js:attribute:: Proxy.uuid

  Contain the unique identifier of the proxy.

  .. warning::
     This attribute is now deprecated and will eventually be removed.
     Please use :js:func:`Proxy.get_uuid()` function instead.

.. js:function:: Proxy.get_uuid()

  Returns the unique identifier of the proxy.

.. js:attribute:: Proxy.servers

  Contain a table with the attached servers. The table is indexed by server
  name, and each server entry is an object of type :ref:`server_class`.

.. js:attribute:: Proxy.stktable

  Contains a stick table object of type :ref:`sticktable_class` attached to the
  proxy.

.. js:attribute:: Proxy.listeners

  Contain a table with the attached listeners. The table is indexed by listener
  name, and each each listeners entry is an object of type
  :ref:`listener_class`.

.. js:function:: Proxy.pause(px)

  Pause the proxy. See the management socket documentation for more information.

  :param class_proxy px: A :ref:`proxy_class` which indicates the manipulated
   proxy.

.. js:function:: Proxy.resume(px)

  Resume the proxy. See the management socket documentation for more
  information.

  :param class_proxy px: A :ref:`proxy_class` which indicates the manipulated
   proxy.

.. js:function:: Proxy.stop(px)

  Stop the proxy. See the management socket documentation for more information.

  :param class_proxy px: A :ref:`proxy_class` which indicates the manipulated
   proxy.

.. js:function:: Proxy.shut_bcksess(px)

  Kill the session attached to a backup server. See the management socket
  documentation for more information.

  :param class_proxy px: A :ref:`proxy_class` which indicates the manipulated
   proxy.

.. js:function:: Proxy.get_cap(px)

  Returns a string describing the capabilities of the proxy.

  :param class_proxy px: A :ref:`proxy_class` which indicates the manipulated
   proxy.
  :returns: a string "frontend", "backend", "proxy" or "ruleset".

.. js:function:: Proxy.get_mode(px)

  Returns a string describing the mode of the current proxy.

  :param class_proxy px: A :ref:`proxy_class` which indicates the manipulated
   proxy.
  :returns: a string "tcp", "http", "syslog" or "unknown"

.. js:function:: Proxy.get_srv_act(px)

  Returns the number of current active servers for the current proxy that are
  eligible for LB.

  :param class_proxy px: A :ref:`proxy_class` which indicates the manipulated
   proxy.
  :returns: an integer

.. js:function:: Proxy.get_srv_bck(px)

  Returns the number backup servers for the current proxy that are eligible
  for LB.

  :param class_proxy px: A :ref:`proxy_class` which indicates the manipulated
   proxy.
  :returns: an integer

.. js:function:: Proxy.get_stats(px)

  Returns a table containing the proxy statistics. The statistics returned are
  not the same if the proxy is frontend or a backend.

  :param class_proxy px: A :ref:`proxy_class` which indicates the manipulated
   proxy.
  :returns: a key/value table containing stats

.. js:function:: Proxy.get_mailers(px)

  **LEGACY**

  Returns a table containing mailers config for the current proxy or nil
  if mailers are not available for the proxy.

  :param class_proxy px: A :ref:`proxy_class` which indicates the manipulated
   proxy.
  :returns: a :ref:`proxy_mailers_class` containing proxy mailers config

.. _proxy_mailers_class:

ProxyMailers class
==================

**LEGACY**

.. js:class:: ProxyMailers

  This class provides mailers config for a given proxy.

  If sending emails directly from lua, please consider
  :js:func:`core.disable_legacy_mailers()` to disable the email sending from
  haproxy. (Or email alerts will be sent twice...)

.. js:attribute:: ProxyMailers.track_server_health

  Boolean set to true if the option "log-health-checks" is configured on
  the proxy, meaning that all server checks event should trigger email alerts.

.. js:attribute:: ProxyMailers.log_level

  An integer, the maximum log level that triggers email alerts. It is a number
  between 0 and 7 as defined by option "email-alert level".

.. js:attribute:: ProxyMailers.mailservers

  An array containing the list of mail servers that should receive email alerts.
  Each array entry is a name:desc pair where desc represents the full server
  address (including port) as described in haproxy's configuration file.

.. js:attribute:: ProxyMailers.mailservers_timeout

  An integer representing the maximum time in milliseconds to wait for the
  email to be sent. See "timeout mail" directive from "mailers" section in
  haproxy configuration file.

.. js:attribute:: ProxyMailers.smtp_hostname

  A string containing the hostname to use for the SMTP transaction.
  (option "email-alert myhostname")

.. js:attribute:: ProxyMailers.smtp_from

  A string containing the "MAIL FROM" address to use for the SMTP transaction.
  (option "email-alert from")

.. js:attribute:: ProxyMailers.smtp_to

  A string containing the "RCPT TO" address to use for the SMTP transaction.
  (option "email-alert to")

.. _server_class:

Server class
============

.. js:class:: Server

  This class provides a way for manipulating servers and retrieving information.

.. js:attribute:: Server.name

  Contain the name of the server.

  .. warning::
     This attribute is now deprecated and will eventually be removed.
     Please use :js:func:`Server.get_name()` function instead.

.. js:function:: Server.get_name(sv)

  Returns the name of the server.

.. js:attribute:: Server.puid

  Contain the proxy unique identifier of the server.

  .. warning::
     This attribute is now deprecated and will eventually be removed.
     Please use :js:func:`Server.get_puid()` function instead.

.. js:function:: Server.get_puid(sv)

  Returns the proxy unique identifier of the server.

.. js:function:: Server.get_rid(sv)

  Returns the rid (revision ID) of the server.
  It is an unsigned integer that is set upon server creation. Value is derived
  from a global counter that starts at 0 and is incremented each time one or
  multiple server deletions are followed by a server addition (meaning that
  old name/id reuse could occur).

  Combining server name/id with server rid yields a process-wide unique
  identifier.

.. js:function:: Server.is_draining(sv)

  Return true if the server is currently draining sticky connections.

  :param class_server sv: A :ref:`server_class` which indicates the manipulated
   server.
  :returns: a boolean

.. js:function:: Server.is_backup(sv)

  Return true if the server is a backup server

  :param class_server sv: A :ref:`server_class` which indicates the manipulated
   server.
  :returns: a boolean

.. js:function:: Server.is_dynamic(sv)

  Return true if the server was instantiated at runtime (e.g.: from the cli)

  :param class_server sv: A :ref:`server_class` which indicates the manipulated
   server.
  :returns: a boolean

.. js:function:: Server.get_cur_sess(sv)

  Return the number of currently active sessions on the server

  :param class_server sv: A :ref:`server_class` which indicates the manipulated
   server.
  :returns: an integer

.. js:function:: Server.get_pend_conn(sv)

  Return the number of pending connections to the server

  :param class_server sv: A :ref:`server_class` which indicates the manipulated
   server.
  :returns: an integer

.. js:function:: Server.set_maxconn(sv, weight)

  Dynamically change the maximum connections of the server. See the management
  socket documentation for more information about the format of the string.

  :param class_server sv: A :ref:`server_class` which indicates the manipulated
   server.
  :param string maxconn: A string describing the server maximum connections.

.. js:function:: Server.get_maxconn(sv, weight)

  This function returns an integer representing the server maximum connections.

  :param class_server sv: A :ref:`server_class` which indicates the manipulated
   server.
  :returns: an integer.

.. js:function:: Server.set_weight(sv, weight)

  Dynamically change the weight of the server. See the management socket
  documentation for more information about the format of the string.

  :param class_server sv: A :ref:`server_class` which indicates the manipulated
   server.
  :param string weight: A string describing the server weight.

.. js:function:: Server.get_weight(sv)

  This function returns an integer representing the server weight.

  :param class_server sv: A :ref:`server_class` which indicates the manipulated
   server.
  :returns: an integer.

.. js:function:: Server.set_addr(sv, addr[, port])

  Dynamically change the address of the server. See the management socket
  documentation for more information about the format of the string.

  :param class_server sv: A :ref:`server_class` which indicates the manipulated
   server.
  :param string addr: A string describing the server address.

.. js:function:: Server.get_addr(sv)

  Returns a string describing the address of the server.

  :param class_server sv: A :ref:`server_class` which indicates the manipulated
   server.
  :returns: A string

.. js:function:: Server.get_stats(sv)

  Returns server statistics.

  :param class_server sv: A :ref:`server_class` which indicates the manipulated
   server.
  :returns: a key/value table containing stats

.. js:function:: Server.get_proxy(sv)

  Returns the parent proxy to which the server belongs.

  :param class_server sv: A :ref:`server_class` which indicates the manipulated
   server.
  :returns: a :ref:`proxy_class` or nil if not available

.. js:function:: Server.shut_sess(sv)

  Shutdown all the sessions attached to the server. See the management socket
  documentation for more information about this function.

  :param class_server sv: A :ref:`server_class` which indicates the manipulated
   server.

.. js:function:: Server.set_drain(sv)

  Drain sticky sessions. See the management socket documentation for more
  information about this function.

  :param class_server sv: A :ref:`server_class` which indicates the manipulated
   server.

.. js:function:: Server.set_maint(sv)

  Set maintenance mode. See the management socket documentation for more
  information about this function.

  :param class_server sv: A :ref:`server_class` which indicates the manipulated
   server.

.. js:function:: Server.set_ready(sv)

  Set normal mode. See the management socket documentation for more information
  about this function.

  :param class_server sv: A :ref:`server_class` which indicates the manipulated
   server.

.. js:function:: Server.check_enable(sv)

  Enable health checks. See the management socket documentation for more
  information about this function.

  :param class_server sv: A :ref:`server_class` which indicates the manipulated
   server.

.. js:function:: Server.check_disable(sv)

  Disable health checks. See the management socket documentation for more
  information about this function.

  :param class_server sv: A :ref:`server_class` which indicates the manipulated
   server.

.. js:function:: Server.check_force_up(sv)

  Force health-check up. See the management socket documentation for more
  information about this function.

  :param class_server sv: A :ref:`server_class` which indicates the manipulated
   server.

.. js:function:: Server.check_force_nolb(sv)

  Force health-check nolb mode. See the management socket documentation for more
  information about this function.

  :param class_server sv: A :ref:`server_class` which indicates the manipulated
   server.

.. js:function:: Server.check_force_down(sv)

  Force health-check down. See the management socket documentation for more
  information about this function.

  :param class_server sv: A :ref:`server_class` which indicates the manipulated
   server.

.. js:function:: Server.agent_enable(sv)

  Enable agent check. See the management socket documentation for more
  information about this function.

  :param class_server sv: A :ref:`server_class` which indicates the manipulated
   server.

.. js:function:: Server.agent_disable(sv)

  Disable agent check. See the management socket documentation for more
  information about this function.

  :param class_server sv: A :ref:`server_class` which indicates the manipulated
   server.

.. js:function:: Server.agent_force_up(sv)

  Force agent check up. See the management socket documentation for more
  information about this function.

  :param class_server sv: A :ref:`server_class` which indicates the manipulated
   server.

.. js:function:: Server.agent_force_down(sv)

  Force agent check down. See the management socket documentation for more
  information about this function.

  :param class_server sv: A :ref:`server_class` which indicates the manipulated
   server.

.. js:function:: Server.tracking(sv)

  Check if the current server is tracking another server.

  :param class_server sv: A :ref:`server_class` which indicates the manipulated
   server.
  :returns: A :ref:`server_class` which indicates the tracked server or nil if
   the server doesn't track another one.

.. js:function:: Server.get_trackers(sv)

  Check if the current server is being tracked by other servers.

  :param class_server sv: A :ref:`server_class` which indicates the manipulated
   server.
  :returns: An array of :ref:`server_class` which indicates the tracking
   servers (might be empty)

.. js:function:: Server.event_sub(sv, event_types, func)

  Register a function that will be called on specific server events.
  It works exactly like :js:func:`core.event_sub()` except that the subscription
  will be performed within the server dedicated subscription list instead of the
  global one.
  (Your callback function will only be called for server events affecting sv)

  See :js:func:`core.event_sub()` for function usage.

  A key advantage to using :js:func:`Server.event_sub()` over
  :js:func:`core.event_sub()` for servers is that :js:func:`Server.event_sub()`
  allows you to be notified for servers events of a single server only.
  It removes the needs for extra filtering in your callback function if you only
  care about a single server, and also prevents useless wakeups.

  For instance, if you want to be notified for UP/DOWN events on a given set of
  servers, it is recommended to perform multiple per-server subscriptions since
  it will be more efficient that doing a single global subscription that will
  filter the received events.
  Unless you really want to be notified for servers events of ALL servers of
  course, which could make sense given you setup but should be avoided if you
  have an important number of servers as it will add a significant load on your
  haproxy process in case of multiple servers state change in a short amount of
  time.

  .. Note::
     You may also combine :js:func:`core.event_sub()` with
     :js:func:`Server.event_sub()`.

     Also, don't forget that you can use :js:func:`core.register_task()` from
     your callback function if needed. (ie: parallel work)

  Here is a working example combining :js:func:`core.event_sub()` with
  :js:func:`Server.event_sub()` and :js:func:`core.register_task()`
  (This only serves as a demo, this is not necessarily useful to do so)

.. code-block:: lua

  core.event_sub({"SERVER_ADD"}, function(event, data, sub)
    -- in the global event handler
    if data["reference"] ~= nil then
      print("Tracking new server: ", data["name"])
      data["reference"]:event_sub({"SERVER_UP", "SERVER_DOWN"}, function(event, data, sub)
        -- in the per-server event handler
	if data["reference"] ~= nil then
          core.register_task(function(server)
            -- subtask to perform some async work (e.g.: HTTP API calls, sending emails...)
            print("ASYNC: SERVER ", server:get_name(), " is ", event == "SERVER_UP" and "UP" or "DOWN")
          end, data["reference"])
        end
      end)
    end
  end)

..

  In this example, we will first track global server addition events.
  For each newly added server ("add server" on the cli), we will register a
  UP/DOWN server subscription.
  Then, the callback function will schedule the event handling in an async
  subtask which will receive the server reference as an argument.

.. _listener_class:

Listener class
==============

.. js:function:: Listener.get_stats(ls)

  Returns server statistics.

  :param class_listener ls: A :ref:`listener_class` which indicates the
   manipulated listener.
  :returns: a key/value table containing stats

.. _event_sub_class:

EventSub class
==============

.. js:function:: EventSub.unsub()

  End the subscription, the callback function will not be called again.

.. _server_event_class:

ServerEvent class
=================

.. js:class:: ServerEvent

This class is provided with every **SERVER** events.

See :js:func:`core.event_sub()` for more info.

.. js:attribute:: ServerEvent.name

  Contains the name of the server.

.. js:attribute:: ServerEvent.puid

  Contains the proxy-unique uid of the server

.. js:attribute:: ServerEvent.rid

  Contains the revision ID of the server

.. js:attribute:: ServerEvent.proxy_name

  Contains the name of the proxy to which the server belongs

.. js:attribute:: ServerEvent.proxy_uuid

  Contains the uuid of the proxy to which the server belongs

.. js:attribute:: ServerEvent.reference

  Reference to the live server (A :ref:`server_class`).

  .. Warning::
     Not available if the server was removed in the meantime.
     (Will never be set for SERVER_DEL event since the server does not exist
     anymore)

.. js:attribute:: ServerEvent.state

  A :ref:`server_event_state_class`

  .. Note::
     Only available for SERVER_STATE event

.. js:attribute:: ServerEvent.admin

  A :ref:`server_event_admin_class`

  .. Note::
     Only available for SERVER_ADMIN event

.. js:attribute:: ServerEvent.check

  A :ref:`server_event_checkres_class`

  .. Note::
     Only available for SERVER_CHECK event

.. _server_event_checkres_class:

ServerEventCheckRes class
=========================

.. js:class:: ServerEventCheckRes

This class describes the result of a server's check.

.. js:attribute:: ServerEventCheckRes.result

  Effective check result.

  Check result is a string and will be set to one of the following values:
    - "FAILED": the check failed
    - "PASSED": the check succeeded
    - "CONDPASS": the check conditionally passed

.. js:attribute:: ServerEventCheckRes.agent

  Boolean set to true if the check is an agent check.
  Else it is a health check.

.. js:attribute:: ServerEventCheckRes.duration

  Check's duration in milliseconds

.. js:attribute:: ServerEventCheckRes.reason

  Check's status. An array containing three fields:
    - **short**: a string representing check status short name
    - **desc**: a string representing check status description
    - **code**: an integer, this extra information is provided for checks
      that went through the data analysis stage (>= layer 5)

.. js:attribute:: ServerEventCheckRes.health

  An array containing values about check's health (integers):
    - **cur**: current health counter:
       - 0 to (**rise** - 1) = BAD
       - **rise** to (**rise** + **fall** - 1) = GOOD
    - **rise**: server will be considered as operational after **rise**
      consecutive successful checks
    - **fall**: server will be considered as dead after **fall** consecutive
      unsuccessful checks

.. _server_event_state_class:

ServerEventState class
======================

.. js:class:: ServerEventState

This class contains additional info related to **SERVER_STATE** event.

.. js:attribute:: ServerEventState.admin

  Boolean set to true if the server state change is due to an administrative
  change. Else it is an operational change.

.. js:attribute:: ServerEventState.check

  A :ref:`server_event_checkres_class`, provided if the state change is
  due to a server check (must be an operational change).

.. js:attribute:: ServerEventState.cause

  Printable state change cause. Might be empty.

.. js:attribute:: ServerEventState.new_state

  New server state due to operational or admin change.

  It is a string that can be any of the following values:
    - "STOPPED": The server is down
    - "STOPPING": The server is up but soft-stopping
    - "STARTING": The server is warming up
    - "RUNNING": The server is fully up

.. js:attribute:: ServerEventState.old_state

  Previous server state prior to the operational or admin change.

  Can be any value described in **new_state**, but they should differ.

.. js:attribute:: ServerEventState.requeued

  Number of connections that were requeued due to the server state change.

  For a server going DOWN: it is the number of pending server connections
  that are requeued to the backend (such connections will be redispatched
  to any server that is suitable according to the configured load balancing
  algorithm).

  For a server doing UP: it is the number of pending connections on the
  backend that may be redispatched to the server according to the load
  balancing algorithm that is in use.

.. _server_event_admin_class:

ServerEventAdmin class
======================

.. js:class:: ServerEventAdmin

This class contains additional info related to **SERVER_ADMIN** event.

.. js:attribute:: ServerEventAdmin.cause

  Printable admin state change cause. Might be empty.

.. js:attribute:: ServerEventAdmin.new_admin

  New server admin state due to the admin change.

  It is an array of string containing a composition of following values:
    - "**MAINT**": server is in maintenance mode
    - "FMAINT": server is in forced maintenance mode (MAINT is also set)
    - "IMAINT": server is in inherited maintenance mode (MAINT is also set)
    - "RMAINT": server is in resolve maintenance mode (MAINT is also set)
    - "CMAINT": server is in config maintenance mode (MAINT is also set)
    - "**DRAIN**": server is in drain mode
    - "FDRAIN": server is in forced drain mode (DRAIN is also set)
    - "IDRAIN": server is in inherited drain mode (DRAIN is also set)

.. js:attribute:: ServerEventAdmin.old_admin

  Previous server admin state prior to the admin change.

  Values are presented as in **new_admin**, but they should differ.
  (Comparing old and new helps to find out the change(s))

.. js:attribute:: ServerEventAdmin.requeued

  Same as :js:attr:`ServerEventState.requeued` but when the requeue is due to
  the server administrative state change.

.. _queue_class:

Queue class
===========

.. js:class:: Queue

  This class provides a generic FIFO storage mechanism that may be shared
  between multiple lua contexts to easily pass data between them, as stock
  Lua doesn't provide easy methods for passing data between multiple coroutines.

  inter-task example:

.. code-block:: lua

  -- script wide shared queue
  local queue = core.queue()

  -- master task
  core.register_task(function()
    -- send the date every second
    while true do
      queue:push(os.date("%c", core.now().sec))
      core.sleep(1)
    end
  end)

  -- worker task
  core.register_task(function()
    while true do
      -- print the date sent by master
      print(queue:pop_wait())
    end
  end)
..

  Of course, queue may also be used as a local storage mechanism.

  Use :js:func:`core.queue` to get a new Queue object.

.. js:function:: Queue.size(queue)

  This function returns the number of items within the Queue.

  :param class_queue queue: A :ref:`queue_class` to the current queue

.. js:function:: Queue.push(queue, item)

  This function pushes the item (may be of any type) to the queue.
  Pushed item cannot be nil or invalid, or an error will be thrown.

  :param class_queue queue: A :ref:`queue_class` to the current queue
  :returns: boolean true for success and false for error

.. js:function:: Queue.pop(queue)

  This function immediately tries to pop an item from the queue.
  It returns nil of no item is available at the time of the call.

  :param class_queue queue: A :ref:`queue_class` to the current queue
  :returns: the item at the top of the stack (any type) or nil if no items

.. js:function:: Queue.pop_wait(queue)

  **context**: task

  This is an alternative to pop() that may be used within task contexts.

  The call waits for data if no item is currently available. This may be
  useful when used in a while loop to prevent cpu waste.

  Note that this requires yielding, thus it is only available within contexts
  that support yielding (mainly task context).

  :param class_queue queue: A :ref:`queue_class` to the current queue
  :returns: the item at the top of the stack (any type) or nil in case of error

.. _concat_class:

Concat class
============

.. js:class:: Concat

  This class provides a fast way for string concatenation. The way using native
  Lua concatenation like the code below is slow for some reasons.

.. code-block:: lua

  str = "string1"
  str = str .. ", string2"
  str = str .. ", string3"
..

  For each concatenation, Lua:
  - allocates memory for the result,
  - catenates the two string copying the strings in the new memory block,
  - frees the old memory block containing the string which is no longer used.

  This process does many memory move, allocation and free. In addition, the
  memory is not really freed, it is just marked as unused and waits for the
  garbage collector.

  The Concat class provides an alternative way to concatenate strings. It uses
  the internal Lua mechanism (it does not allocate memory), but it doesn't copy
  the data more than once.

  On my computer, the following loops spends 0.2s for the Concat method and
  18.5s for the pure Lua implementation. So, the Concat class is about 1000x
  faster than the embedded solution.

.. code-block:: lua

  for j = 1, 100 do
    c = core.concat()
    for i = 1, 20000 do
      c:add("#####")
    end
  end
..

.. code-block:: lua

  for j = 1, 100 do
    c = ""
    for i = 1, 20000 do
      c = c .. "#####"
    end
  end
..

.. js:function:: Concat.add(concat, string)

  This function adds a string to the current concatenated string.

  :param class_concat concat: A :ref:`concat_class` which contains the currently
   built string.
  :param string string: A new string to concatenate to the current built
   string.

.. js:function:: Concat.dump(concat)

  This function returns the concatenated string.

  :param class_concat concat: A :ref:`concat_class` which contains the currently
   built string.
  :returns: the concatenated string

.. _fetches_class:

Fetches class
=============

.. js:class:: Fetches

  This class contains a lot of internal HAProxy sample fetches. See the
  HAProxy "configuration.txt" documentation for more information.
  (chapters 7.3.2 to 7.3.6)

  .. warning::
     some sample fetches are not available in some context. These limitations
     are specified in this documentation when they're useful.

  :see: :js:attr:`TXN.f`
  :see: :js:attr:`TXN.sf`

  Fetches are useful to:

  * get system time,
  * get environment variable,
  * get random numbers,
  * know backend status like the number of users in queue or the number of
    connections established,
  * get client information like ip source or destination,
  * deal with stick tables,
  * fetch established SSL information,
  * fetch HTTP information like headers or method.

.. code-block:: lua

  function action(txn)
    -- Get source IP
    local clientip = txn.f:src()
  end
..

.. _converters_class:

Converters class
================

.. js:class:: Converters

  This class contains a lot of internal HAProxy sample converters. See the
  HAProxy documentation "configuration.txt" for more information about her
  usage. Its the chapter 7.3.1.

  :see: :js:attr:`TXN.c`
  :see: :js:attr:`TXN.sc`

  Converters provides stateful transformation. They are useful to:

  * convert input to base64,
  * apply hash on input string (djb2, crc32, sdbm, wt6),
  * format date,
  * json escape,
  * extract preferred language comparing two lists,
  * turn to lower or upper chars,
  * deal with stick tables.

.. _channel_class:

Channel class
=============

.. js:class:: Channel

  **context**: action, sample-fetch, convert, filter

  HAProxy uses two buffers for the processing of the requests. The first one is
  used with the request data (from the client to the server) and the second is
  used for the response data (from the server to the client).

  Each buffer contains two types of data. The first type is the incoming data
  waiting for a processing. The second part is the outgoing data already
  processed. Usually, the incoming data is processed, after it is tagged as
  outgoing data, and finally it is sent. The following functions provides tools
  for manipulating these data in a buffer.

  The following diagram shows where the channel class function are applied.

  .. image:: _static/channel.png

  .. warning::
    It is not possible to read from the response in request action, and it is
    not possible to read from the request channel in response action.

  .. warning::
    It is forbidden to alter the Channels buffer from HTTP contexts.  So only
    :js:func:`Channel.input`, :js:func:`Channel.output`,
    :js:func:`Channel.may_recv`, :js:func:`Channel.is_full` and
    :js:func:`Channel.is_resp` can be called from a HTTP context.

  All the functions provided by this class are available in the
  **sample-fetches**, **actions** and **filters** contexts. For **filters**,
  incoming data (offset and length) are relative to the filter. Some functions
  may yield, but only for **actions**. Yield is not possible for
  **sample-fetches**, **converters** and **filters**.

.. js:function:: Channel.append(channel, string)

  This function copies the string **string** at the end of incoming data of the
  channel buffer. The function returns the copied length on success or -1 if
  data cannot be copied.

  Same that :js:func:`Channel.insert(channel, string, channel:input())`.

  :param class_channel channel: The manipulated Channel.
  :param string string: The data to copy at the end of incoming data.
  :returns: an integer containing the amount of bytes copied or -1.

.. js:function:: Channel.data(channel [, offset [, length]])

  This function returns **length** bytes of incoming data from the channel
  buffer, starting at the offset **offset**. The data are not removed from the
  buffer.

  By default, if no length is provided, all incoming data found, starting at the
  given offset, are returned. If **length** is set to -1, the function tries to
  retrieve a maximum of data and, if called by an action, it yields if
  necessary. It also waits for more data if the requested length exceeds the
  available amount of incoming data. Not providing an offset is the same as
  setting it to 0. A positive offset is relative to the beginning of incoming
  data of the channel buffer while negative offset is relative to the end.

  If there is no incoming data and the channel can't receive more data, a 'nil'
  value is returned.

  :param class_channel channel: The manipulated Channel.
  :param integer offset: *optional* The offset in incoming data to start to get
   data. 0 by default. May be negative to be relative to the end of incoming
   data.
  :param integer length: *optional* The expected length of data to retrieve. All
   incoming data by default. May be set to -1 to get a maximum of data.
  :returns: a string containing the data found or nil.

.. js:function:: Channel.forward(channel, length)

  This function forwards **length** bytes of data from the channel buffer. If
  the requested length exceeds the available amount of incoming data, and if
  called by an action, the function yields, waiting for more data to forward. It
  returns the amount of data forwarded.

  :param class_channel channel: The manipulated Channel.
  :param integer int: The amount of data to forward.

.. js:function:: Channel.input(channel)

  This function returns the length of incoming data in the channel buffer. When
  called by a filter, this value is relative to the filter.

  :param class_channel channel: The manipulated Channel.
  :returns: an integer containing the amount of available bytes.

.. js:function:: Channel.insert(channel, string [, offset])

  This function copies the string **string** at the offset **offset** in
  incoming data of the channel buffer. The function returns the copied length on
  success or -1 if data cannot be copied.

  By default, if no offset is provided, the string is copied in front of
  incoming data. A positive offset is relative to the beginning of incoming data
  of the channel buffer while negative offset is relative to their end.

  :param class_channel channel: The manipulated Channel.
  :param string string: The data to copy into incoming data.
  :param integer offset: *optional* The offset in incoming data where to copy
   data. 0 by default. May be negative to be relative to the end of incoming
   data.
  :returns: an integer containing the amount of bytes copied or -1.

.. js:function:: Channel.is_full(channel)

  This function returns true if the channel buffer is full.

  :param class_channel channel: The manipulated Channel.
  :returns: a boolean

.. js:function:: Channel.is_resp(channel)

  This function returns true if the channel is the response one.

  :param class_channel channel: The manipulated Channel.
  :returns: a boolean

.. js:function:: Channel.line(channel [, offset [, length]])

  This function parses **length** bytes of incoming data of the channel buffer,
  starting at offset **offset**, and returns the first line found, including the
  '\\n'.  The data are not removed from the buffer. If no line is found, all
  data are returned.

  By default, if no length is provided, all incoming data, starting at the given
  offset, are evaluated. If **length** is set to -1, the function tries to
  retrieve a maximum of data and, if called by an action, yields if
  necessary. It also waits for more data if the requested length exceeds the
  available amount of incoming data. Not providing an offset is the same as
  setting it to 0. A positive offset is relative to the beginning of incoming
  data of the channel buffer while negative offset is relative to the end.

  If there is no incoming data and the channel can't receive more data, a 'nil'
  value is returned.

  :param class_channel channel: The manipulated Channel.
  :param integer offset: *optional* The offset in incoming data to start to
   parse data. 0 by default. May be negative to be relative to the end of
   incoming data.
  :param integer length: *optional* The length of data to parse. All incoming
   data by default. May be set to -1 to get a maximum of data.
  :returns: a string containing the line found or nil.

.. js:function:: Channel.may_recv(channel)

  This function returns true if the channel may still receive data.

  :param class_channel channel: The manipulated Channel.
  :returns: a boolean

.. js:function:: Channel.output(channel)

  This function returns the length of outgoing data of the channel buffer. When
  called by a filter, this value is relative to the filter.

  :param class_channel channel: The manipulated Channel.
  :returns: an integer containing the amount of available bytes.

.. js:function:: Channel.prepend(channel, string)

  This function copies the string **string** in front of incoming data of the
  channel buffer. The function returns the copied length on success or -1 if
  data cannot be copied.

  Same that :js:func:`Channel.insert(channel, string, 0)`.

  :param class_channel channel: The manipulated Channel.
  :param string string: The data to copy in front of incoming data.
  :returns: an integer containing the amount of bytes copied or -1.

.. js:function:: Channel.remove(channel [, offset [, length]])

  This function removes **length** bytes of incoming data of the channel buffer,
  starting at offset **offset**. This function returns number of bytes removed
  on success.

  By default, if no length is provided, all incoming data, starting at the given
  offset, are removed. Not providing an offset is the same as setting it
  to 0. A positive offset is relative to the beginning of incoming data of the
  channel buffer while negative offset is relative to the end.

  :param class_channel channel: The manipulated Channel.
  :param integer offset: *optional* The offset in incoming data where to start
   to remove data. 0 by default. May be negative to be relative to the end of
   incoming data.
  :param integer length: *optional* The length of data to remove. All incoming
   data by default.
  :returns: an integer containing the amount of bytes removed.

.. js:function:: Channel.send(channel, string)

  This function requires immediate send of the string **string**. It means the
  string is copied at the beginning of incoming data of the channel buffer and
  immediately forwarded. Unless if the connection is close, and if called by an
  action, this function yields to copy and forward all the string.

  :param class_channel channel: The manipulated Channel.
  :param string string: The data to send.
  :returns: an integer containing the amount of bytes copied or -1.

.. js:function:: Channel.set(channel, string [, offset [, length]])

  This function replaces **length** bytes of incoming data of the channel
  buffer, starting at offset **offset**, by the string **string**. The function
  returns the copied length on success or -1 if data cannot be copied.

  By default, if no length is provided, all incoming data, starting at the given
  offset, are replaced. Not providing an offset is the same as setting it
  to 0. A positive offset is relative to the beginning of incoming data of the
  channel buffer while negative offset is relative to the end.

  :param class_channel channel: The manipulated Channel.
  :param string string: The data to copy into incoming data.
  :param integer offset: *optional* The offset in incoming data where to start
   the data replacement. 0 by default. May be negative to be relative to the
   end of incoming data.
  :param integer length: *optional* The length of data to replace. All incoming
   data by default.
  :returns: an integer containing the amount of bytes copied or -1.

.. js:function:: Channel.dup(channel)

  **DEPRECATED**

  This function returns all incoming data found in the channel buffer. The data
  are not removed from the buffer and can be reprocessed later.

  If there is no incoming data and the channel can't receive more data, a 'nil'
  value is returned.

  :param class_channel channel: The manipulated Channel.
  :returns: a string containing all data found or nil.

  .. warning::
     This function is deprecated. :js:func:`Channel.data()` must be used
     instead.

.. js:function:: Channel.get(channel)

  **DEPRECATED**

  This function returns all incoming data found in the channel buffer and remove
  them from the buffer.

  If there is no incoming data and the channel can't receive more data, a 'nil'
  value is returned.

  :param class_channel channel: The manipulated Channel.
  :returns: a string containing all the data found or nil.

  .. warning::
     This function is deprecated. :js:func:`Channel.data()` must be used to
     retrieve data followed by a call to :js:func:`Channel:remove()` to remove
     data.

     .. code-block:: lua

       local data = chn:data()
       chn:remove(0, data:len())

     ..

.. js:function:: Channel.getline(channel)

  **DEPRECATED**

  This function returns the first line found in incoming data of the channel
  buffer, including the '\\n'. The returned data are removed from the buffer. If
  no line is found, and if called by an action, this function yields to wait for
  more data, except if the channel can't receive more data. In this case all
  data are returned.

  If there is no incoming data and the channel can't receive more data, a 'nil'
  value is returned.

  :param class_channel channel: The manipulated Channel.
  :returns: a string containing the line found or nil.

  .. warning::
     This function is deprecated. :js:func:`Channel.line()` must be used to
     retrieve a line followed by a call to :js:func:`Channel:remove()` to remove
     data.

     .. code-block:: lua

       local line = chn:line(0, -1)
       chn:remove(0, line:len())

     ..

.. js:function:: Channel.get_in_len(channel)

  **DEPRECATED**

  This function returns the length of the input part of the buffer. When called
  by a filter, this value is relative to the filter.

  :param class_channel channel: The manipulated Channel.
  :returns: an integer containing the amount of available bytes.

  .. warning::
     This function is deprecated. :js:func:`Channel.input()` must be used
     instead.

.. js:function:: Channel.get_out_len(channel)

  **DEPRECATED**

  This function returns the length of the output part of the buffer. When called
  by a filter, this value is relative to the filter.

  :param class_channel channel: The manipulated Channel.
  :returns: an integer containing the amount of available bytes.

  .. warning::
     This function is deprecated. :js:func:`Channel.output()` must be used
     instead.

.. _http_class:

HTTP class
==========

.. js:class:: HTTP

   This class contain all the HTTP manipulation functions.

.. js:function:: HTTP.req_get_headers(http)

  Returns a table containing all the request headers.

  :param class_http http: The related http object.
  :returns: table of headers.
  :see: :js:func:`HTTP.res_get_headers`

  This is the form of the returned table:

.. code-block:: lua

  HTTP:req_get_headers()['<header-name>'][<header-index>] = "<header-value>"

  local hdr = HTTP:req_get_headers()
  hdr["host"][0] = "www.test.com"
  hdr["accept"][0] = "audio/basic q=1"
  hdr["accept"][1] = "audio/*, q=0.2"
  hdr["accept"][2] = "*/*, q=0.1"
..

.. js:function:: HTTP.res_get_headers(http)

  Returns a table containing all the response headers.

  :param class_http http: The related http object.
  :returns: table of headers.
  :see: :js:func:`HTTP.req_get_headers`

  This is the form of the returned table:

.. code-block:: lua

  HTTP:res_get_headers()['<header-name>'][<header-index>] = "<header-value>"

  local hdr = HTTP:req_get_headers()
  hdr["host"][0] = "www.test.com"
  hdr["accept"][0] = "audio/basic q=1"
  hdr["accept"][1] = "audio/*, q=0.2"
  hdr["accept"][2] = "*.*, q=0.1"
..

.. js:function:: HTTP.req_add_header(http, name, value)

  Appends a HTTP header field in the request whose name is
  specified in "name" and whose value is defined in "value".

  :param class_http http: The related http object.
  :param string name: The header name.
  :param string value: The header value.
  :see: :js:func:`HTTP.res_add_header`

.. js:function:: HTTP.res_add_header(http, name, value)

  Appends a HTTP header field in the response whose name is
  specified in "name" and whose value is defined in "value".

  :param class_http http: The related http object.
  :param string name: The header name.
  :param string value: The header value.
  :see: :js:func:`HTTP.req_add_header`

.. js:function:: HTTP.req_del_header(http, name)

  Removes all HTTP header fields in the request whose name is
  specified in "name".

  :param class_http http: The related http object.
  :param string name: The header name.
  :see: :js:func:`HTTP.res_del_header`

.. js:function:: HTTP.res_del_header(http, name)

  Removes all HTTP header fields in the response whose name is
  specified in "name".

  :param class_http http: The related http object.
  :param string name: The header name.
  :see: :js:func:`HTTP.req_del_header`

.. js:function:: HTTP.req_set_header(http, name, value)

  This variable replace all occurrence of all header "name", by only
  one containing the "value".

  :param class_http http: The related http object.
  :param string name: The header name.
  :param string value: The header value.
  :see: :js:func:`HTTP.res_set_header`

  This function does the same work as the following code:

.. code-block:: lua

   function fcn(txn)
      TXN.http:req_del_header("header")
      TXN.http:req_add_header("header", "value")
   end
..

.. js:function:: HTTP.res_set_header(http, name, value)

  This function replaces all occurrence of all header "name", by only
  one containing the "value".

  :param class_http http: The related http object.
  :param string name: The header name.
  :param string value: The header value.
  :see: :js:func:`HTTP.req_rep_header()`

.. js:function:: HTTP.req_rep_header(http, name, regex, replace)

  Matches the regular expression in all occurrences of header field "name"
  according to "regex", and replaces them with the "replace" argument. The
  replacement value can contain back references like \1, \2, ... This
  function works with the request.

  :param class_http http: The related http object.
  :param string name: The header name.
  :param string regex: The match regular expression.
  :param string replace: The replacement value.
  :see: :js:func:`HTTP.res_rep_header()`

.. js:function:: HTTP.res_rep_header(http, name, regex, string)

  Matches the regular expression in all occurrences of header field "name"
  according to "regex", and replaces them with the "replace" argument. The
  replacement value can contain back references like \1, \2, ... This
  function works with the request.

  :param class_http http: The related http object.
  :param string name: The header name.
  :param string regex: The match regular expression.
  :param string replace: The replacement value.
  :see: :js:func:`HTTP.req_rep_header()`

.. js:function:: HTTP.req_set_method(http, method)

  Rewrites the request method with the parameter "method".

  :param class_http http: The related http object.
  :param string method: The new method.

.. js:function:: HTTP.req_set_path(http, path)

  Rewrites the request path with the "path" parameter.

  :param class_http http: The related http object.
  :param string path: The new path.

.. js:function:: HTTP.req_set_query(http, query)

  Rewrites the request's query string which appears after the first question
  mark ("?") with the parameter "query".

  :param class_http http: The related http object.
  :param string query: The new query.

.. js:function:: HTTP.req_set_uri(http, uri)

  Rewrites the request URI with the parameter "uri".

  :param class_http http: The related http object.
  :param string uri: The new uri.

.. js:function:: HTTP.res_set_status(http, status [, reason])

  Rewrites the response status code with the parameter "code".

  If no custom reason is provided, it will be generated from the status.

  :param class_http http: The related http object.
  :param integer status: The new response status code.
  :param string reason: The new response reason (optional).

.. _httpclient_class:

HTTPClient class
================

.. js:class:: HTTPClient

   The httpclient class allows issue of outbound HTTP requests through a simple
   API without the knowledge of HAProxy internals.

.. js:function:: HTTPClient.get(httpclient, request)
.. js:function:: HTTPClient.head(httpclient, request)
.. js:function:: HTTPClient.put(httpclient, request)
.. js:function:: HTTPClient.post(httpclient, request)
.. js:function:: HTTPClient.delete(httpclient, request)

  Send a HTTP request and wait for a response. GET, HEAD PUT, POST and DELETE
  methods can be used.
  The HTTPClient will send asynchronously the data and is able to send and
  receive more than HAProxy bufsize.

  The HTTPClient interface is not able to decompress responses, it is not
  recommended to send an Accept-Encoding in the request so the response is
  received uncompressed.

  :param class httpclient: Is the manipulated HTTPClient.
  :param table request: Is a table containing the parameters of the request
   that will be send.
  :param string request.url: Is a mandatory parameter for the request that
   contains the URL.
  :param string request.body: Is an optional parameter for the request that
   contains the body to send.
  :param table request.headers: Is an optional parameter for the request that
   contains the headers to send.
  :param string request.dst: Is an optional parameter for the destination in
   haproxy address format.
  :param integer request.timeout: Optional timeout parameter, set a
   "timeout server" on the connections.
  :returns: Lua table containing the response


.. code-block:: lua

  local httpclient = core.httpclient()
  local response = httpclient:post{url="http://127.0.0.1", body=body, dst="unix@/var/run/http.sock"}

..

.. code-block:: lua

 response = {
    status  = 400,
    reason  = "Bad request",
    headers = {
        ["content-type"]  = { "text/html" },
        ["cache-control"] = { "no-cache", "no-store" },
    },
    body = "<html><body><h1>invalid request<h1></body></html>",
  }
..


.. _txn_class:

TXN class
=========

.. js:class:: TXN

  The txn class contain all the functions relative to the http or tcp
  transaction (Note than a tcp stream is the same than a tcp transaction, but
  a HTTP transaction is not the same than a tcp stream).

  The usage of this class permits to retrieve data from the requests, alter it
  and forward it.

  All the functions provided by this class are available in the context
  **sample-fetches**, **actions** and **filters**.

.. js:attribute:: TXN.c

  :returns: An :ref:`converters_class`.

  This attribute contains a Converters class object.

.. js:attribute:: TXN.sc

  :returns: An :ref:`converters_class`.

  This attribute contains a Converters class object. The functions of
  this object returns always a string.

.. js:attribute:: TXN.f

  :returns: An :ref:`fetches_class`.

  This attribute contains a Fetches class object.

.. js:attribute:: TXN.sf

  :returns: An :ref:`fetches_class`.

  This attribute contains a Fetches class object. The functions of
  this object returns always a string.

.. js:attribute:: TXN.req

  :returns: An :ref:`channel_class`.

  This attribute contains a channel class object for the request buffer.

.. js:attribute:: TXN.res

  :returns: An :ref:`channel_class`.

  This attribute contains a channel class object for the response buffer.

.. js:attribute:: TXN.http

  :returns: An :ref:`http_class`.

  This attribute contains a HTTP class object. It is available only if the
  proxy has the "mode http" enabled.

.. js:attribute:: TXN.http_req

  :returns: An :ref:`httpmessage_class`.

  This attribute contains the request HTTPMessage class object. It is available
  only if the proxy has the "mode http" enabled and only in the **filters**
  context.

.. js:attribute:: TXN.http_res

  :returns: An :ref:`httpmessage_class`.

  This attribute contains the response HTTPMessage class object. It is available
  only if the proxy has the "mode http" enabled and only in the **filters**
  context.

.. js:function:: TXN.log(TXN, loglevel, msg)

  This function sends a log. The log is sent, according with the HAProxy
  configuration file, to the loggers relevant to the current context and/or
  to stderr if it is allowed.

  The exact behaviour depends on tune.lua.log.loggers and tune.lua.log.stderr.

  :param class_txn txn: The class txn object containing the data.
  :param integer loglevel: Is the log level associated with the message. It is
   a number between 0 and 7.
  :param string msg: The log content.
  :see: :js:attr:`core.emerg`, :js:attr:`core.alert`, :js:attr:`core.crit`,
    :js:attr:`core.err`, :js:attr:`core.warning`, :js:attr:`core.notice`,
    :js:attr:`core.info`, :js:attr:`core.debug` (log level definitions)
  :see: :js:func:`TXN.deflog`
  :see: :js:func:`TXN.Debug`
  :see: :js:func:`TXN.Info`
  :see: :js:func:`TXN.Warning`
  :see: :js:func:`TXN.Alert`

.. js:function:: TXN.deflog(TXN, msg)

  Sends a log line with the default loglevel for the proxy associated with the
  transaction.

  :param class_txn txn: The class txn object containing the data.
  :param string msg: The log content.
  :see: :js:func:`TXN.log`

.. js:function:: TXN.Debug(txn, msg)

  :param class_txn txn: The class txn object containing the data.
  :param string msg: The log content.
  :see: :js:func:`TXN.log`

  Does the same job as:

.. code-block:: lua

  function Debug(txn, msg)
    TXN.log(txn, core.debug, msg)
  end
..

.. js:function:: TXN.Info(txn, msg)

  :param class_txn txn: The class txn object containing the data.
  :param string msg: The log content.
  :see: :js:func:`TXN.log`

  Does the same job as:

.. code-block:: lua

  function Info(txn, msg)
    TXN.log(txn, core.info, msg)
  end
..

.. js:function:: TXN.Warning(txn, msg)

  :param class_txn txn: The class txn object containing the data.
  :param string msg: The log content.
  :see: :js:func:`TXN.log`

  Does the same job as:

.. code-block:: lua

  function Warning(txn, msg)
    TXN.log(txn, core.warning, msg)
  end
..

.. js:function:: TXN.Alert(txn, msg)

  :param class_txn txn: The class txn object containing the data.
  :param string msg: The log content.
  :see: :js:func:`TXN.log`

  Does the same job as:

.. code-block:: lua

  function Alert(txn, msg)
    TXN.log(txn, core.alert, msg)
  end
..

.. js:function:: TXN.get_priv(txn)

  Return Lua data stored in the current transaction (with the `TXN.set_priv()`)
  function. If no data are stored, it returns a nil value.

  :param class_txn txn: The class txn object containing the data.
  :returns: the opaque data previously stored, or nil if nothing is
   available.

.. js:function:: TXN.set_priv(txn, data)

  Store any data in the current HAProxy transaction. This action replaces the
  old stored data.

  :param class_txn txn: The class txn object containing the data.
  :param opaque data: The data which is stored in the transaction.

.. js:function:: TXN.set_var(TXN, var, value[, ifexist])

  Converts a Lua type in a HAProxy type and store it in a variable <var>.

  :param class_txn txn: The class txn object containing the data.
  :param string var: The variable name according with the HAProxy variable
   syntax.
  :param type value: The value associated to the variable. The type can be
   string or integer.
  :param boolean ifexist: If this parameter is set to true the variable will
   only be set if it was defined elsewhere (i.e. used within the configuration).
   For global variables (using the "proc" scope), they will only be updated and
   never created. It is highly recommended to always set this to true.

.. js:function:: TXN.unset_var(TXN, var)

  Unset the variable <var>.

  :param class_txn txn: The class txn object containing the data.
  :param string var: The variable name according with the HAProxy variable
   syntax.

.. js:function:: TXN.get_var(TXN, var)

  Returns data stored in the variable <var> converter in Lua type.

  :param class_txn txn: The class txn object containing the data.
  :param string var: The variable name according with the HAProxy variable
   syntax.

.. js:function:: TXN.reply([reply])

  Return a new reply object

  :param table reply: A table containing info to initialize the reply fields.
  :returns: A :ref:`reply_class` object.

  The table used to initialized the reply object may contain following entries :

  * status : The reply status code. the code 200 is used by default.
  * reason : The reply reason. The reason corresponding to the status code is
    used by default.
  * headers : A list of headers, indexed by header name. Empty by default. For
    a given name, multiple values are possible, stored in an ordered list.
  * body : The reply body, empty by default.

.. code-block:: lua

  local reply = txn:reply{
      status  = 400,
      reason  = "Bad request",
      headers = {
          ["content-type"]  = { "text/html" },
          ["cache-control"] = {"no-cache", "no-store" }
      },
      body = "<html><body><h1>invalid request<h1></body></html>"
  }
..
  :see: :js:class:`Reply`

.. js:function:: TXN.done(txn[, reply])

  This function terminates processing of the transaction and the associated
  session and optionally reply to the client for HTTP sessions.

  :param class_txn txn: The class txn object containing the data.
  :param class_reply reply: The class reply object to return to the client.

  This functions can be used when a critical error is detected or to terminate
  processing after some data have been returned to the client (eg: a redirect).
  To do so, a reply may be provided. This object is optional and may contain a
  status code, a reason, a header list and a body. All these fields are
  optional. When not provided, the default values are used. By default, with an
  empty reply object, an empty HTTP 200 response is returned to the client. If
  no reply object is provided, the transaction is terminated without any
  reply. If a reply object is provided, it must not exceed the buffer size once
  converted into the internal HTTP representation. Because for now there is no
  easy way to be sure it fits, it is probably better to keep it reasonably
  small.

  The reply object may be fully created in lua or the class Reply may be used to
  create it.

.. code-block:: lua

  local reply = txn:reply()
  reply:set_status(400, "Bad request")
  reply:add_header("content-type", "text/html")
  reply:add_header("cache-control", "no-cache")
  reply:add_header("cache-control", "no-store")
  reply:set_body("<html><body><h1>invalid request<h1></body></html>")
  txn:done(reply)
..

.. code-block:: lua

   txn:done{
       status  = 400,
       reason  = "Bad request",
       headers = {
           ["content-type"]  = { "text/html" },
           ["cache-control"] = { "no-cache", "no-store" },
       },
       body = "<html><body><h1>invalid request<h1></body></html>"
   }
..

  .. warning::
    It does not make sense to call this function from sample-fetches. In this
    case the behavior is the same than core.done(): it finishes the Lua
    execution. The transaction is really aborted only from an action registered
    function.

  :see: :js:func:`TXN.reply`, :js:class:`Reply`

.. js:function:: TXN.set_loglevel(txn, loglevel)

  Is used to change the log level of the current request. The "loglevel" must
  be an integer between 0 and 7.

  :param class_txn txn: The class txn object containing the data.
  :param integer loglevel: The required log level. This variable can be one of
  :see: :js:attr:`core.emerg`, :js:attr:`core.alert`, :js:attr:`core.crit`,
    :js:attr:`core.err`, :js:attr:`core.warning`, :js:attr:`core.notice`,
    :js:attr:`core.info`, :js:attr:`core.debug` (log level definitions)

.. js:function:: TXN.set_tos(txn, tos)

  Is used to set the TOS or DSCP field value of packets sent to the client to
  the value passed in "tos" on platforms which support this.

  :param class_txn txn: The class txn object containing the data.
  :param integer tos: The new TOS os DSCP.

.. js:function:: TXN.set_mark(txn, mark)

  Is used to set the Netfilter MARK on all packets sent to the client to the
  value passed in "mark" on platforms which support it.

  :param class_txn txn: The class txn object containing the data.
  :param integer mark: The mark value.

.. js:function:: TXN.set_priority_class(txn, prio)

  This function adjusts the priority class of the transaction. The value should
  be within the range -2047..2047. Values outside this range will be
  truncated.

  See the HAProxy configuration.txt file keyword "http-request" action
  "set-priority-class" for details.

.. js:function:: TXN.set_priority_offset(txn, prio)

  This function adjusts the priority offset of the transaction. The value
  should be within the range -524287..524287. Values outside this range will be
  truncated.

  See the HAProxy configuration.txt file keyword "http-request" action
  "set-priority-offset" for details.

.. _reply_class:

Reply class
============

.. js:class:: Reply

  **context**: action

  This class represents a HTTP response message. It provides some methods to
  enrich it. Once converted into the internal HTTP representation, the response
  message must not exceed the buffer size. Because for now there is no
  easy way to be sure it fits, it is probably better to keep it reasonably
  small.

  See tune.bufsize in the configuration manual for details.

.. code-block:: lua

  local reply = txn:reply({status = 400}) -- default HTTP 400 reason-phase used
  reply:add_header("content-type", "text/html")
  reply:add_header("cache-control", "no-cache")
  reply:add_header("cache-control", "no-store")
  reply:set_body("<html><body><h1>invalid request<h1></body></html>")
..

  :see: :js:func:`TXN.reply`

.. js:attribute:: Reply.status

  The reply status code. By default, the status code is set to 200.

  :returns: integer

.. js:attribute:: Reply.reason

  The reason string describing the status code.

  :returns: string

.. js:attribute:: Reply.headers

  A table indexing all reply headers by name. To each name is associated an
  ordered list of values.

  :returns: Lua table

.. code-block:: lua

  {
    ["content-type"]  = { "text/html" },
    ["cache-control"] = {"no-cache", "no-store" },
    x_header_name     = { "value1", "value2", ... }
    ...
  }
..

.. js:attribute:: Reply.body

  The reply payload.

  :returns: string

.. js:function:: Reply.set_status(REPLY, status[, reason])

  Set the reply status code and optionally the reason-phrase. If the reason is
  not provided, the default reason corresponding to the status code is used.

  :param class_reply reply: The related Reply object.
  :param integer status: The reply status code.
  :param string reason: The reply status reason (optional).

.. js:function:: Reply.add_header(REPLY, name, value)

  Add a header to the reply object. If the header does not already exist, a new
  entry is created with its name as index and a one-element list containing its
  value as value. Otherwise, the header value is appended to the ordered list of
  values associated to the header name.

  :param class_reply reply: The related Reply object.
  :param string name: The header field name.
  :param string value: The header field value.

.. js:function:: Reply.del_header(REPLY, name)

  Remove all occurrences of a header name from the reply object.

  :param class_reply reply: The related Reply object.
  :param string name: The header field name.

.. js:function:: Reply.set_body(REPLY, body)

  Set the reply payload.

  :param class_reply reply: The related Reply object.
  :param string body: The reply payload.

.. _socket_class:

Socket class
============

.. js:class:: Socket

  This class must be compatible with the Lua Socket class. Only the 'client'
  functions are available. See the Lua Socket documentation:

  `http://w3.impa.br/~diego/software/luasocket/tcp.html
  <http://w3.impa.br/~diego/software/luasocket/tcp.html>`_

.. js:function:: Socket.close(socket)

  Closes a TCP object. The internal socket used by the object is closed and the
  local address to which the object was bound is made available to other
  applications. No further operations (except for further calls to the close
  method) are allowed on a closed Socket.

  :param class_socket socket: Is the manipulated Socket.

  Note: It is important to close all used sockets once they are not needed,
  since, in many systems, each socket uses a file descriptor, which are limited
  system resources. Garbage-collected objects are automatically closed before
  destruction, though.

.. js:function:: Socket.connect(socket, address[, port])

  Attempts to connect a socket object to a remote host.


  In case of error, the method returns nil followed by a string describing the
  error. In case of success, the method returns 1.

  :param class_socket socket: Is the manipulated Socket.
  :param string address: can be an IP address or a host name. See below for more
   information.
  :param integer port: must be an integer number in the range [1..64K].
  :returns: 1 or nil.

  An address field extension permits to use the connect() function to connect to
  other stream than TCP. The syntax containing a simpleipv4 or ipv6 address is
  the basically expected format. This format requires the port.

  Other format accepted are a socket path like "/socket/path", it permits to
  connect to a socket. Abstract namespaces are supported with the prefix
  "abns@", and finally a file descriptor can be passed with the prefix "fd@".
  The prefix "ipv4@", "ipv6@" and "unix@" are also supported. The port can be
  passed int the string. The syntax "127.0.0.1:1234" is valid. In this case, the
  parameter *port* must not be set.

.. js:function:: Socket.connect_ssl(socket, address, port)

  Same behavior than the function socket:connect, but uses SSL.

  :param class_socket socket: Is the manipulated Socket.
  :returns: 1 or nil.

.. js:function:: Socket.getpeername(socket)

  Returns information about the remote side of a connected client object.

  Returns a string with the IP address of the peer, followed by the port number
  that peer is using for the connection. In case of error, the method returns
  nil.

  :param class_socket socket: Is the manipulated Socket.
  :returns: a string containing the server information.

.. js:function:: Socket.getsockname(socket)

  Returns the local address information associated to the object.

  The method returns a string with local IP address and a number with the port.
  In case of error, the method returns nil.

  :param class_socket socket: Is the manipulated Socket.
  :returns: a string containing the client information.

.. js:function:: Socket.receive(socket, [pattern [, prefix]])

  Reads data from a client object, according to the specified read pattern.
  Patterns follow the Lua file I/O format, and the difference in performance
  between all patterns is negligible.

  :param class_socket socket: Is the manipulated Socket.
  :param string|integer pattern: Describe what is required (see below).
  :param string prefix: A string which will be prefix the returned data.
  :returns:  a string containing the required data or nil.

  Pattern can be any of the following:

  * **`*a`**: reads from the socket until the connection is closed. No
              end-of-line translation is performed;

  * **`*l`**: reads a line of text from the Socket. The line is terminated by a
              LF character (ASCII 10), optionally preceded by a CR character
              (ASCII 13). The CR and LF characters are not included in the
              returned line.  In fact, all CR characters are ignored by the
              pattern. This is the default pattern.

  * **number**: causes the method to read a specified number of bytes from the
                Socket. Prefix is an optional string to be concatenated to the
                beginning of any received data before return.

  * **empty**: If the pattern is left empty, the default option is `*l`.

  If successful, the method returns the received pattern. In case of error, the
  method returns nil followed by an error message which can be the string
  'closed' in case the connection was closed before the transmission was
  completed or the string 'timeout' in case there was a timeout during the
  operation. Also, after the error message, the function returns the partial
  result of the transmission.

  Important note: This function was changed severely. It used to support
  multiple patterns (but I have never seen this feature used) and now it
  doesn't anymore.  Partial results used to be returned in the same way as
  successful results. This last feature violated the idea that all functions
  should return nil on error.  Thus it was changed too.

.. js:function:: Socket.send(socket, data [, start [, end ]])

  Sends data through client object.

  :param class_socket socket: Is the manipulated Socket.
  :param string data: The data that will be sent.
  :param integer start: The start position in the buffer of the data which will
   be sent.
  :param integer end: The end position in the buffer of the data which will
   be sent.
  :returns: see below.

  Data is the string to be sent. The optional arguments i and j work exactly
  like the standard string.sub Lua function to allow the selection of a
  substring to be sent.

  If successful, the method returns the index of the last byte within [start,
  end] that has been sent. Notice that, if start is 1 or absent, this is
  effectively the total number of bytes sent. In case of error, the method
  returns nil, followed by an error message, followed by the index of the last
  byte within [start, end] that has been sent. You might want to try again from
  the byte following that. The error message can be 'closed' in case the
  connection was closed before the transmission was completed or the string
  'timeout' in case there was a timeout during the operation.

  Note: Output is not buffered. For small strings, it is always better to
  concatenate them in Lua (with the '..' operator) and send the result in one
  call instead of calling the method several times.

.. js:function:: Socket.setoption(socket, option [, value])

  Just implemented for compatibility, this cal does nothing.

.. js:function:: Socket.settimeout(socket, value [, mode])

  Changes the timeout values for the object. All I/O operations are blocking.
  That is, any call to the methods send, receive, and accept will block
  indefinitely, until the operation completes. The settimeout method defines a
  limit on the amount of time the I/O methods can block. When a timeout time
  has elapsed, the affected methods give up and fail with an error code.

  The amount of time to wait is specified as the value parameter, in seconds.

  The timeout modes are not implemented, the only settable timeout is the
  inactivity time waiting for complete the internal buffer send or waiting for
  receive data.

  :param class_socket socket: Is the manipulated Socket.
  :param float value: The timeout value. Use floating point to specify
   milliseconds.

.. _regex_class:

Regex class
===========

.. js:class:: Regex

  This class allows the usage of HAProxy regexes because classic lua doesn't
  provides regexes. This class inherits the HAProxy compilation options, so the
  regexes can be libc regex, pcre regex or pcre JIT regex.

  The expression matching number is limited to 20 per regex. The only available
  option is case sensitive.

  Because regexes compilation is a heavy process, it is better to define all
  your regexes in the **body context** and use it during the runtime.

.. code-block:: lua

  -- Create the regex
  st, regex = Regex.new("needle (..) (...)", true);

  -- Check compilation errors
  if st == false then
    print "error: " .. regex
  end

  -- Match the regexes
  print(regex:exec("Looking for a needle in the haystack")) -- true
  print(regex:exec("Lokking for a cat in the haystack"))    -- false

  -- Extract words
  st, list = regex:match("Looking for a needle in the haystack")
  print(st)      -- true
  print(list[1]) -- needle in the
  print(list[2]) -- in
  print(list[3]) -- the

.. js:function:: Regex.new(regex, case_sensitive)

  Create and compile a regex.

  :param string regex: The regular expression according with the libc or pcre
   standard
  :param boolean case_sensitive: Match is case sensitive or not.
  :returns: boolean status and :ref:`regex_class` or string containing fail
   reason.

.. js:function:: Regex.exec(regex, str)

  Execute the regex.

  :param class_regex regex: A :ref:`regex_class` object.
  :param string str: The input string will be compared with the compiled regex.
  :returns: a boolean status according with the match result.

.. js:function:: Regex.match(regex, str)

  Execute the regex and return matched expressions.

  :param class_map map: A :ref:`regex_class` object.
  :param string str: The input string will be compared with the compiled regex.
  :returns: a boolean status according with the match result, and
   a table containing all the string matched in order of declaration.

.. _map_class:

Map class
=========

.. js:class:: Map

  This class permits to do some lookups in HAProxy maps. The declared maps can
  be modified during the runtime through the HAProxy management socket.

.. code-block:: lua

  default = "usa"

  -- Create and load map
  geo = Map.new("geo.map", Map._ip);

  -- Create new fetch that returns the user country
  core.register_fetches("country", function(txn)
    local src;
    local loc;

    src = txn.f:fhdr("x-forwarded-for");
    if (src == nil) then
      src = txn.f:src()
      if (src == nil) then
        return default;
      end
    end

    -- Perform lookup
    loc = geo:lookup(src);

    if (loc == nil) then
      return default;
    end

    return loc;
  end);

.. js:attribute:: Map._int

  See the HAProxy configuration.txt file, chapter "Using ACLs and fetching
  samples" and subchapter "ACL basics" to understand this pattern matching
  method.

  Note that :js:attr:`Map.int` is also available for compatibility.

.. js:attribute:: Map._ip

  See the HAProxy configuration.txt file, chapter "Using ACLs and fetching
  samples" and subchapter "ACL basics" to understand this pattern matching
  method.

  Note that :js:attr:`Map.ip` is also available for compatibility.

.. js:attribute:: Map._str

  See the HAProxy configuration.txt file, chapter "Using ACLs and fetching
  samples" and subchapter "ACL basics" to understand this pattern matching
  method.

  Note that :js:attr:`Map.str` is also available for compatibility.

.. js:attribute:: Map._beg

  See the HAProxy configuration.txt file, chapter "Using ACLs and fetching
  samples" and subchapter "ACL basics" to understand this pattern matching
  method.

  Note that :js:attr:`Map.beg` is also available for compatibility.

.. js:attribute:: Map._sub

  See the HAProxy configuration.txt file, chapter "Using ACLs and fetching
  samples" and subchapter "ACL basics" to understand this pattern matching
  method.

  Note that :js:attr:`Map.sub` is also available for compatibility.

.. js:attribute:: Map._dir

  See the HAProxy configuration.txt file, chapter "Using ACLs and fetching
  samples" and subchapter "ACL basics" to understand this pattern matching
  method.

  Note that :js:attr:`Map.dir` is also available for compatibility.

.. js:attribute:: Map._dom

  See the HAProxy configuration.txt file, chapter "Using ACLs and fetching
  samples" and subchapter "ACL basics" to understand this pattern matching
  method.

  Note that :js:attr:`Map.dom` is also available for compatibility.

.. js:attribute:: Map._end

  See the HAProxy configuration.txt file, chapter "Using ACLs and fetching
  samples" and subchapter "ACL basics" to understand this pattern matching
  method.

.. js:attribute:: Map._reg

  See the HAProxy configuration.txt file, chapter "Using ACLs and fetching
  samples" and subchapter "ACL basics" to understand this pattern matching
  method.

  Note that :js:attr:`Map.reg` is also available for compatibility.


.. js:function:: Map.new(file, method)

  Creates and load a map.

  :param string file: Is the file containing the map.
  :param integer method: Is the map pattern matching method. See the attributes
   of the Map class.
  :returns: a class Map object.
  :see: The Map attributes: :js:attr:`Map._int`, :js:attr:`Map._ip`,
    :js:attr:`Map._str`, :js:attr:`Map._beg`, :js:attr:`Map._sub`,
    :js:attr:`Map._dir`, :js:attr:`Map._dom`, :js:attr:`Map._end` and
    :js:attr:`Map._reg`.

.. js:function:: Map.lookup(map, str)

  Perform a lookup in a map.

  :param class_map map: Is the class Map object.
  :param string str: Is the string used as key.
  :returns: a string containing the result or nil if no match.

.. js:function:: Map.slookup(map, str)

  Perform a lookup in a map.

  :param class_map map: Is the class Map object.
  :param string str: Is the string used as key.
  :returns: a string containing the result or empty string if no match.

.. _applethttp_class:

AppletHTTP class
================

.. js:class:: AppletHTTP

  This class is used with applets that requires the 'http' mode. The http applet
  can be registered with the *core.register_service()* function. They are used
  for processing an http request like a server in back of HAProxy.

  This is an hello world sample code:

.. code-block:: lua

  core.register_service("hello-world", "http", function(applet)
     local response = "Hello World !"
     applet:set_status(200)
     applet:add_header("content-length", string.len(response))
     applet:add_header("content-type", "text/plain")
     applet:start_response()
     applet:send(response)
  end)

.. js:attribute:: AppletHTTP.c

  :returns: A :ref:`converters_class`

  This attribute contains a Converters class object.

.. js:attribute:: AppletHTTP.sc

  :returns: A :ref:`converters_class`

  This attribute contains a Converters class object. The
  functions of this object always return a string.

.. js:attribute:: AppletHTTP.f

  :returns: A :ref:`fetches_class`

  This attribute contains a Fetches class object. Note that the
  applet execution place cannot access to a valid HAProxy core HTTP
  transaction, so some sample fetches related to the HTTP dependent
  values (hdr, path, ...) are not available.

.. js:attribute:: AppletHTTP.sf

  :returns: A :ref:`fetches_class`

  This attribute contains a Fetches class object. The functions of
  this object always return a string. Note that the applet
  execution place cannot access to a valid HAProxy core HTTP
  transaction, so some sample fetches related to the HTTP dependent
  values (hdr, path, ...) are not available.

.. js:attribute:: AppletHTTP.method

  :returns: string

  The attribute method returns a string containing the HTTP
  method.

.. js:attribute:: AppletHTTP.version

  :returns: string

  The attribute version, returns a string containing the HTTP
  request version.

.. js:attribute:: AppletHTTP.path

  :returns: string

  The attribute path returns a string containing the HTTP
  request path.

.. js:attribute:: AppletHTTP.qs

  :returns: string

  The attribute qs returns a string containing the HTTP
  request query string.

.. js:attribute:: AppletHTTP.length

  :returns: integer

  The attribute length returns an integer containing the HTTP
  body length.

.. js:attribute:: AppletHTTP.headers

  :returns: table

  The attribute headers returns a table containing the HTTP
  headers. The header names are always in lower case. As the header name can be
  encountered more than once in each request, the value is indexed with 0 as
  first index value. The table has this form:

.. code-block:: lua

  AppletHTTP.headers['<header-name>'][<header-index>] = "<header-value>"

  AppletHTTP.headers["host"][0] = "www.test.com"
  AppletHTTP.headers["accept"][0] = "audio/basic q=1"
  AppletHTTP.headers["accept"][1] = "audio/*, q=0.2"
  AppletHTTP.headers["accept"][2] = "*/*, q=0.1"
..

.. js:function:: AppletHTTP.set_status(applet, code [, reason])

  This function sets the HTTP status code for the response. The allowed code are
  from 100 to 599.

  :param class_AppletHTTP applet: An :ref:`applethttp_class`
  :param integer code: the status code returned to the client.
  :param string reason: the status reason returned to the client (optional).

.. js:function:: AppletHTTP.add_header(applet, name, value)

  This function adds a header in the response. Duplicated headers are not
  collapsed. The special header *content-length* is used to determinate the
  response length. If it does not exist, a *transfer-encoding: chunked* is set,
  and all the write from the function *AppletHTTP:send()* become a chunk.

  :param class_AppletHTTP applet: An :ref:`applethttp_class`
  :param string name: the header name
  :param string value: the header value

.. js:function:: AppletHTTP.start_response(applet)

  This function indicates to the HTTP engine that it can process and send the
  response headers. After this called we cannot add headers to the response; We
  cannot use the *AppletHTTP:send()* function if the
  *AppletHTTP:start_response()* is not called.

  :param class_AppletHTTP applet: An :ref:`applethttp_class`

.. js:function:: AppletHTTP.getline(applet)

  This function returns a string containing one line from the http body. If the
  data returned doesn't contains a final '\\n' its assumed than its the last
  available data before the end of stream.

  :param class_AppletHTTP applet: An :ref:`applethttp_class`
  :returns: a string. The string can be empty if we reach the end of the stream.

.. js:function:: AppletHTTP.receive(applet, [size])

  Reads data from the HTTP body, according to the specified read *size*. If the
  *size* is missing, the function tries to read all the content of the stream
  until the end. If the *size* is bigger than the http body, it returns the
  amount of data available.

  :param class_AppletHTTP applet: An :ref:`applethttp_class`
  :param integer size: the required read size.
  :returns: always return a string,the string can be empty is the connection is
   closed.

.. js:function:: AppletHTTP.send(applet, msg)

  Send the message *msg* on the http request body.

  :param class_AppletHTTP applet: An :ref:`applethttp_class`
  :param string msg: the message to send.

.. js:function:: AppletHTTP.get_priv(applet)

  Return Lua data stored in the current transaction. If no data are stored,
  it returns a nil value.

  :param class_AppletHTTP applet: An :ref:`applethttp_class`
  :returns: the opaque data previously stored, or nil if nothing is
   available.
  :see: :js:func:`AppletHTTP.set_priv`

.. js:function:: AppletHTTP.set_priv(applet, data)

  Store any data in the current HAProxy transaction. This action replaces the
  old stored data.

  :param class_AppletHTTP applet: An :ref:`applethttp_class`
  :param opaque data: The data which is stored in the transaction.
  :see: :js:func:`AppletHTTP.get_priv`

.. js:function:: AppletHTTP.set_var(applet, var, value[, ifexist])

  Converts a Lua type in a HAProxy type and store it in a variable <var>.

  :param class_AppletHTTP applet: An :ref:`applethttp_class`
  :param string var: The variable name according with the HAProxy variable
   syntax.
  :param type value: The value associated to the variable. The type ca be string
   or integer.
  :param boolean ifexist: If this parameter is set to true the variable will
   only be set if it was defined elsewhere (i.e. used within the configuration).
   For global variables (using the "proc" scope), they will only be updated and
   never created. It is highly recommended to always set this to true.

  :see: :js:func:`AppletHTTP.unset_var`
  :see: :js:func:`AppletHTTP.get_var`

.. js:function:: AppletHTTP.unset_var(applet, var)

  Unset the variable <var>.

  :param class_AppletHTTP applet: An :ref:`applethttp_class`
  :param string var: The variable name according with the HAProxy variable
   syntax.
  :see: :js:func:`AppletHTTP.set_var`
  :see: :js:func:`AppletHTTP.get_var`

.. js:function:: AppletHTTP.get_var(applet, var)

  Returns data stored in the variable <var> converter in Lua type.

  :param class_AppletHTTP applet: An :ref:`applethttp_class`
  :param string var: The variable name according with the HAProxy variable
   syntax.
  :see: :js:func:`AppletHTTP.set_var`
  :see: :js:func:`AppletHTTP.unset_var`

.. _applettcp_class:

AppletTCP class
===============

.. js:class:: AppletTCP

  This class is used with applets that requires the 'tcp' mode. The tcp applet
  can be registered with the *core.register_service()* function. They are used
  for processing a tcp stream like a server in back of HAProxy.

.. js:attribute:: AppletTCP.c

  :returns: A :ref:`converters_class`

  This attribute contains a Converters class object.

.. js:attribute:: AppletTCP.sc

  :returns: A :ref:`converters_class`

  This attribute contains a Converters class object. The
  functions of this object always return a string.

.. js:attribute:: AppletTCP.f

  :returns: A :ref:`fetches_class`

  This attribute contains a Fetches class object.

.. js:attribute:: AppletTCP.sf

  :returns: A :ref:`fetches_class`

  This attribute contains a Fetches class object.

.. js:function:: AppletTCP.getline(applet)

  This function returns a string containing one line from the stream. If the
  data returned doesn't contains a final '\\n' its assumed than its the last
  available data before the end of stream.

  :param class_AppletTCP applet: An :ref:`applettcp_class`
  :returns: a string. The string can be empty if we reach the end of the stream.

.. js:function:: AppletTCP.receive(applet, [size])

  Reads data from the TCP stream, according to the specified read *size*. If the
  *size* is missing, the function tries to read all the content of the stream
  until the end.

  :param class_AppletTCP applet: An :ref:`applettcp_class`
  :param integer size: the required read size.
  :returns: always return a string, the string can be empty if the connection is
   closed.

.. js:function:: AppletTCP.send(appletmsg)

  Send the message on the stream.

  :param class_AppletTCP applet: An :ref:`applettcp_class`
  :param string msg: the message to send.

.. js:function:: AppletTCP.get_priv(applet)

  Return Lua data stored in the current transaction. If no data are stored,
  it returns a nil value.

  :param class_AppletTCP applet: An :ref:`applettcp_class`
  :returns: the opaque data previously stored, or nil if nothing is
   available.
  :see: :js:func:`AppletTCP.set_priv`

.. js:function:: AppletTCP.set_priv(applet, data)

  Store any data in the current HAProxy transaction. This action replaces the
  old stored data.

  :param class_AppletTCP applet: An :ref:`applettcp_class`
  :param opaque data: The data which is stored in the transaction.
  :see: :js:func:`AppletTCP.get_priv`

.. js:function:: AppletTCP.set_var(applet, var, value[, ifexist])

  Converts a Lua type in a HAProxy type and stores it in a variable <var>.

  :param class_AppletTCP applet: An :ref:`applettcp_class`
  :param string var: The variable name according with the HAProxy variable
   syntax.
  :param type value: The value associated to the variable. The type can be
   string or integer.
  :param boolean ifexist: If this parameter is set to true the variable will
   only be set if it was defined elsewhere (i.e. used within the configuration).
   For global variables (using the "proc" scope), they will only be updated and
   never created. It is highly recommended to always set this to true.

  :see: :js:func:`AppletTCP.unset_var`
  :see: :js:func:`AppletTCP.get_var`

.. js:function:: AppletTCP.unset_var(applet, var)

  Unsets the variable <var>.

  :param class_AppletTCP applet: An :ref:`applettcp_class`
  :param string var: The variable name according with the HAProxy variable
   syntax.
  :see: :js:func:`AppletTCP.unset_var`
  :see: :js:func:`AppletTCP.set_var`

.. js:function:: AppletTCP.get_var(applet, var)

  Returns data stored in the variable <var> converter in Lua type.

  :param class_AppletTCP applet: An :ref:`applettcp_class`
  :param string var: The variable name according with the HAProxy variable
   syntax.
  :see: :js:func:`AppletTCP.unset_var`
  :see: :js:func:`AppletTCP.set_var`

.. _sticktable_class:

StickTable class
================

.. js:class:: StickTable

  **context**: task, action, sample-fetch

  This class can be used to access the HAProxy stick tables from Lua.

.. js:function:: StickTable.info()

  Returns stick table attributes as a Lua table. See HAProxy documentation for
  "stick-table" for canonical info, or check out example below.

  :returns: Lua table

  Assume our table has IPv4 key and gpc0 and conn_rate "columns":

.. code-block:: lua

  {
    expire=<int>,  # Value in ms
    size=<int>,    # Maximum table size
    used=<int>,    # Actual number of entries in table
    data={         # Data columns, with types as key, and periods as values
                     (-1 if type is not rate counter)
      conn_rate=<int>,
      gpc0=-1
    },
    length=<int>,  # max string length for string table keys, key length
                   # otherwise
    nopurge=<boolean>, # purge oldest entries when table is full
    type="ip"      # can be "ip", "ipv6", "integer", "string", "binary"
  }

.. js:function:: StickTable.lookup(key)

   Returns stick table entry for given <key>

   :param string key: Stick table key (IP addresses and strings are supported)
   :returns: Lua table

.. js:function:: StickTable.dump([filter])

   Returns all entries in stick table. An optional filter can be used
   to extract entries with specific data values. Filter is a table with valid
   comparison operators as keys followed by data type name and value pairs.
   Check out the HAProxy docs for "show table" for more details. For the
   reference, the supported operators are:

     "eq", "ne", "le", "lt", "ge", "gt"

   For large tables, execution of this function can take a long time (for
   HAProxy standards). That's also true when filter is used, so take care and
   measure the impact.

   :param table filter: Stick table filter
   :returns: Stick table entries (table)

   See below for example filter, which contains 4 entries (or comparisons).
   (Maximum number of filter entries is 4, defined in the source code)

.. code-block:: lua

    local filter = {
      {"gpc0", "gt", 30}, {"gpc1", "gt", 20}}, {"conn_rate", "le", 10}
    }

.. _action_class:

Action class
=============

.. js:class:: Act

  **context**: action

  This class contains all return codes an action may return. It is the lua
  equivalent to HAProxy "ACT_RET_*" code.

.. code-block:: lua

  core.register_action("deny", { "http-req" }, function (txn)
      return act.DENY
   end)
..
.. js:attribute:: act.CONTINUE

  This attribute is an integer (0). It instructs HAProxy to continue the
  current ruleset processing on the message. It is the default return code
  for a lua action.

  :returns: integer

.. js:attribute:: act.STOP

  This attribute is an integer (1). It instructs HAProxy to stop the current
  ruleset processing on the message.

.. js:attribute:: act.YIELD

  This attribute is an integer (2). It instructs HAProxy to temporarily pause
  the message processing. It will be resumed later on the same rule. The
  corresponding lua script is re-executed for the start.

.. js:attribute:: act.ERROR

  This attribute is an integer (3). It triggers an internal errors The message
  processing is stopped and the transaction is terminated. For HTTP streams, an
  HTTP 500 error is returned to the client.

  :returns: integer

.. js:attribute:: act.DONE

  This attribute is an integer (4). It instructs HAProxy to stop the message
  processing.

  :returns: integer

.. js:attribute:: act.DENY

  This attribute is an integer (5). It denies the current message. The message
  processing is stopped and the transaction is terminated. For HTTP streams, an
  HTTP 403 error is returned to the client if the deny is returned during the
  request analysis. During the response analysis, a HTTP 502 error is returned
  and the server response is discarded.

  :returns: integer

.. js:attribute:: act.ABORT

  This attribute is an integer (6). It aborts the current message. The message
  processing is stopped and the transaction is terminated. For HTTP streams,
  HAProxy assumes a response was already sent to the client. From the Lua
  actions point of view, when this code is used, the transaction is terminated
  with no reply.

  :returns: integer

.. js:attribute:: act.INVALID

  This attribute is an integer (7). It triggers an internal errors. The message
  processing is stopped and the transaction is terminated. For HTTP streams, an
  HTTP 400 error is returned to the client if the error is returned during the
  request analysis. During the response analysis, a HTTP 502 error is returned
  and the server response is discarded.

  :returns: integer

.. js:function:: act:wake_time(milliseconds)

  **context**: action

  Set the script pause timeout to the specified time, defined in
  milliseconds.

  :param integer milliseconds: the required milliseconds.

  This function may be used when a lua action returns `act.YIELD`, to force its
  wake-up at most after the specified number of milliseconds.

.. _filter_class:

Filter class
=============

.. js:class:: filter

  **context**: filter

  This class contains return codes some filter callback functions may return. It
  also contains configuration flags and some helper functions. To understand how
  the filter API works, see `doc/internal/filters.txt` documentation.

.. js:attribute:: filter.CONTINUE

  This attribute is an integer (1). It may be returned by some filter callback
  functions to instruct this filtering step is finished for this filter.

.. js:attribute:: filter.WAIT

  This attribute is an integer (0). It may be returned by some filter callback
  functions to instruct the filtering must be paused, waiting for more data or
  for an external event depending on this filter.

.. js:attribute:: filter.ERROR

  This attribute is an integer (-1). It may be returned by some filter callback
  functions to trigger an error.

.. js:attribute:: filter.FLT_CFG_FL_HTX

  This attribute is a flag corresponding to the filter flag FLT_CFG_FL_HTX. When
  it is set for a filter, it means the filter is able to filter HTTP streams.

.. js:function:: filter.register_data_filter(chn)

  **context**: filter

  Enable the data filtering on the channel **chn** for the current filter. It
  may be called at any time from any callback functions proceeding the data
  analysis.

  :param class_Channel chn: A :ref:`channel_class`.

.. js:function:: filter.unregister_data_filter(chn)

  **context**: filter

  Disable the data filtering on the channel **chn** for the current filter. It
  may be called at any time from any callback functions.

  :param class_Channel chn: A :ref:`channel_class`.

.. js:function:: filter.wake_time(milliseconds)

  **context**: filter

  Set the script pause timeout to the specified time, defined in
  milliseconds.

  :param integer milliseconds: the required milliseconds.

  This function may be used from any lua filter callback function to force its
  wake-up at most after the specified number of milliseconds. Especially, when
  `filter.CONTINUE` is returned.


A filters is declared using :js:func:`core.register_filter()` function. The
provided class will be used to instantiate filters. It may define following
attributes:

* id: The filter identifier. It is a string that identifies the filter and is
      optional.

* flags: The filter flags. Only :js:attr:`filter.FLT_CFG_FL_HTX` may be set
         for now.

Such filter class must also define all required callback functions in the
following list. Note that :js:func:`Filter.new()` must be defined otherwise the
filter is ignored. Others are optional.

* .. js:function:: FILTER.new()

  Called to instantiate a new filter. This function must be defined.

  :returns: a Lua object that will be used as filter instance for the current
            stream.

* .. js:function:: FILTER.start_analyze(flt, txn, chn)

  Called when the analysis starts on the channel **chn**.

* .. js:function:: FILTER.end_analyze(flt, txn, chn)

  Called when the analysis ends on the channel **chn**.

* .. js:function:: FILTER.http_headers(flt, txn, http_msg)

  Called just before the HTTP payload analysis and after any processing on the
  HTTP message **http_msg**. This callback functions is only called for HTTP
  streams.

* .. js:function:: FILTER.http_payload(flt, txn, http_msg)

  Called during the HTTP payload analysis on the HTTP message **http_msg**. This
  callback functions is only called for HTTP streams.

* .. js:function:: FILTER.http_end(flt, txn, http_msg)

  Called after the HTTP payload analysis on the HTTP message **http_msg**. This
  callback functions is only called for HTTP streams.

* .. js:function:: FILTER.tcp_payload(flt, txn, chn)

  Called during the TCP payload analysis on the channel **chn**.

Here is a full example:

.. code-block:: lua

  Trace = {}
  Trace.id = "Lua trace filter"
  Trace.flags = filter.FLT_CFG_FL_HTX;
  Trace.__index = Trace

  function Trace:new()
      local trace = {}
      setmetatable(trace, Trace)
      trace.req_len = 0
      trace.res_len = 0
      return trace
  end

  function Trace:start_analyze(txn, chn)
      if chn:is_resp() then
          print("Start response analysis")
      else
          print("Start request analysis")
      end
      filter.register_data_filter(self, chn)
  end

  function Trace:end_analyze(txn, chn)
      if chn:is_resp() then
          print("End response analysis: "..self.res_len.." bytes filtered")
      else
          print("End request analysis: "..self.req_len.." bytes filtered")
      end
  end

  function Trace:http_headers(txn, http_msg)
      stline  = http_msg:get_stline()
      if http_msg.channel:is_resp() then
          print("response:")
          print(stline.version.." "..stline.code.." "..stline.reason)
      else
          print("request:")
          print(stline.method.." "..stline.uri.." "..stline.version)
      end

      for n, hdrs in pairs(http_msg:get_headers()) do
          for i,v in pairs(hdrs) do
              print(n..": "..v)
          end
      end
      return filter.CONTINUE
  end

  function Trace:http_payload(txn, http_msg)
      body = http_msg:body(-20000)
      if http_msg.channel:is_resp() then
          self.res_len = self.res_len + body:len()
      else
          self.req_len = self.req_len + body:len()
      end
  end

  core.register_filter("trace", Trace, function(trace, args)
      return trace
  end)

..

.. _httpmessage_class:

HTTPMessage class
===================

.. js:class:: HTTPMessage

  **context**: filter

  This class contains all functions to manipulate a HTTP message. For now, this
  class is only available from a filter context.

.. js:function:: HTTPMessage.add_header(http_msg, name, value)

  Appends a HTTP header field in the HTTP message **http_msg** whose name is
  specified in **name** and whose value is defined in **value**.

  :param class_httpmessage http_msg: The manipulated HTTP message.
  :param string name: The header name.
  :param string value: The header value.

.. js:function:: HTTPMessage.append(http_msg, string)

  This function copies the string **string** at the end of incoming data of the
  HTTP message **http_msg**. The function returns the copied length on success
  or -1 if data cannot be copied.

  Same that :js:func:`HTTPMessage.insert(http_msg, string, http_msg:input())`.

  :param class_httpmessage http_msg: The manipulated HTTP message.
  :param string string: The data to copy at the end of incoming data.
  :returns: an integer containing the amount of bytes copied or -1.

.. js:function:: HTTPMessage.body(http_msgl[, offset[, length]])

  This function returns **length** bytes of incoming data from the HTTP message
  **http_msg**, starting at the offset **offset**. The data are not removed from
  the buffer.

  By default, if no length is provided, all incoming data found, starting at the
  given offset, are returned. If **length** is set to -1, the function tries to
  retrieve a maximum of data. Because it is called in the filter context, it
  never yield. Not providing an offset is the same as setting it to 0. A
  positive offset is relative to the beginning of incoming data of the
  http_message buffer while negative offset is relative to their end.

  If there is no incoming data and the HTTP message can't receive more data,
  a 'nil' value is returned.

  :param class_httpmessage http_msg: The manipulated HTTP message.
  :param integer offset: *optional* The offset in incoming data to start to get
   data. 0 by default. May be negative to be relative to the end of incoming
   data.
  :param integer length: *optional* The expected length of data to retrieve.
   All incoming data by default. May be set to -1 to get a maximum of data.
  :returns: a string containing the data found or nil.

.. js:function:: HTTPMessage.eom(http_msg)

  This function returns true if the end of message is reached for the HTTP
  message **http_msg**.

  :param class_httpmessage http_msg: The manipulated HTTP message.
  :returns: an integer containing the amount of available bytes.

.. js:function:: HTTPMessage.del_header(http_msg, name)

  Removes all HTTP header fields in the HTTP message **http_msg** whose name is
  specified in **name**.

  :param class_httpmessage http_msg: The manipulated http message.
  :param string name: The header name.

.. js:function:: HTTPMessage.get_headers(http_msg)

  Returns a table containing all the headers of the HTTP message **http_msg**.

  :param class_httpmessage http_msg: The manipulated http message.
  :returns: table of headers.

  This is the form of the returned table:

.. code-block:: lua

  http_msg:get_headers()['<header-name>'][<header-index>] = "<header-value>"

  local hdr = http_msg:get_headers()
  hdr["host"][0] = "www.test.com"
  hdr["accept"][0] = "audio/basic q=1"
  hdr["accept"][1] = "audio/*, q=0.2"
  hdr["accept"][2] = "*.*, q=0.1"
..

.. js:function:: HTTPMessage.get_stline(http_msg)

  Returns a table containing the start-line of the HTTP message **http_msg**.

  :param class_httpmessage http_msg: The manipulated http message.
  :returns: the start-line.

  This is the form of the returned table:

.. code-block:: lua

  -- for the request :
  {"method" = string, "uri" = string, "version" = string}

  -- for the response:
  {"version" = string, "code" = string, "reason" = string}
..

.. js:function:: HTTPMessage.forward(http_msg, length)

  This function forwards **length** bytes of data from the HTTP message
  **http_msg**. Because it is called in the filter context, it never yields. Only
  available incoming data may be forwarded, event if the requested length
  exceeds the available amount of incoming data. It returns the amount of data
  forwarded.

  :param class_httpmessage http_msg: The manipulated HTTP message.
  :param integer int: The amount of data to forward.

.. js:function:: HTTPMessage.input(http_msg)

  This function returns the length of incoming data in the HTTP message
  **http_msg** from the filter point of view.

  :param class_httpmessage http_msg: The manipulated HTTP message.
  :returns: an integer containing the amount of available bytes.

.. js:function:: HTTPMessage.insert(http_msg, string[, offset])

  This function copies the string **string** at the offset **offset** in
  incoming data of the HTTP message **http_msg**. The function returns the
  copied length on success or -1 if data cannot be copied.

  By default, if no offset is provided, the string is copied in front of
  incoming data. A positive offset is relative to the beginning of incoming data
  of the HTTP message while negative offset is relative to their end.

  :param class_httpmessage http_msg: The manipulated HTTP message.
  :param string string: The data to copy into incoming data.
  :param integer offset: *optional* The offset in incoming data where to copy
   data. 0 by default. May be negative to be relative to the end of incoming
   data.
  :returns: an integer containing the amount of bytes copied or -1.

.. js:function:: HTTPMessage.is_full(http_msg)

  This function returns true if the HTTP message **http_msg** is full.

  :param class_httpmessage http_msg: The manipulated HTTP message.
  :returns: a boolean

.. js:function:: HTTPMessage.is_resp(http_msg)

  This function returns true if the HTTP message **http_msg** is the response
  one.

  :param class_httpmessage http_msg: The manipulated HTTP message.
  :returns: a boolean

.. js:function:: HTTPMessage.may_recv(http_msg)

  This function returns true if the HTTP message **http_msg** may still receive
  data.

  :param class_httpmessage http_msg: The manipulated HTTP message.
  :returns: a boolean

.. js:function:: HTTPMessage.output(http_msg)

  This function returns the length of outgoing data of the HTTP message
  **http_msg**.

  :param class_httpmessage http_msg: The manipulated HTTP message.
  :returns: an integer containing the amount of available bytes.

.. js:function:: HTTPMessage.prepend(http_msg, string)

  This function copies the string **string** in front of incoming data of the
  HTTP message **http_msg**. The function returns the copied length on success
  or -1 if data cannot be copied.

  Same that :js:func:`HTTPMessage.insert(http_msg, string, 0)`.

  :param class_httpmessage http_msg: The manipulated HTTP message.
  :param string string: The data to copy in front of incoming data.
  :returns: an integer containing the amount of bytes copied or -1.

.. js:function:: HTTPMessage.remove(http_msg[, offset[, length]])

  This function removes **length** bytes of incoming data of the HTTP message
  **http_msg**, starting at offset **offset**. This function returns number of
  bytes removed on success.

  By default, if no length is provided, all incoming data, starting at the given
  offset, are removed. Not providing an offset is the same that setting it
  to 0. A positive offset is relative to the beginning of incoming data of the
  HTTP message while negative offset is relative to the end.

  :param class_httpmessage http_msg: The manipulated HTTP message.
  :param integer offset: *optional* The offset in incoming data where to start
   to remove data. 0 by default. May be negative to be relative to the end of
   incoming data.
  :param integer length: *optional* The length of data to remove. All incoming
   data by default.
  :returns: an integer containing the amount of bytes removed.

.. js:function:: HTTPMessage.rep_header(http_msg, name, regex, replace)

  Matches the regular expression in all occurrences of header field **name**
  according to regex **regex**, and replaces them with the string **replace**.
  The replacement value can contain back references like \1, \2, ... This
  function acts on whole header lines, regardless of the number of values they
  may contain.

  :param class_httpmessage http_msg: The manipulated HTTP message.
  :param string name: The header name.
  :param string regex: The match regular expression.
  :param string replace: The replacement value.

.. js:function:: HTTPMessage.rep_value(http_msg, name, regex, replace)

  Matches the regular expression on every comma-delimited value of header field
  **name** according to regex **regex**, and replaces them with the string
  **replace**.  The replacement value can contain back references like \1, \2,
  ...

  :param class_httpmessage http_msg: The manipulated HTTP message.
  :param string name: The header name.
  :param string regex: The match regular expression.
  :param string replace: The replacement value.

.. js:function:: HTTPMessage.send(http_msg, string)

  This function requires immediate send of the string **string**. It means the
  string is copied at the beginning of incoming data of the HTTP message
  **http_msg** and immediately forwarded. Because it is called in the filter
  context, it never yields.

  :param class_httpmessage http_msg: The manipulated HTTP message.
  :param string string: The data to send.
  :returns: an integer containing the amount of bytes copied or -1.

.. js:function:: HTTPMessage.set(http_msg, string[, offset[, length]])

  This function replaces **length** bytes of incoming data of the HTTP message
  **http_msg**, starting at offset **offset**, by the string **string**. The
  function returns the copied length on success or -1 if data cannot be copied.

  By default, if no length is provided, all incoming data, starting at the given
  offset, are replaced. Not providing an offset is the same as setting it
  to 0. A positive offset is relative to the beginning of incoming data of the
  HTTP message while negative offset is relative to the end.

  :param class_httpmessage http_msg: The manipulated HTTP message.
  :param string string: The data to copy into incoming data.
  :param integer offset: *optional* The offset in incoming data where to start
   the data replacement. 0 by default. May be negative to be relative to the
   end of incoming data.
  :param integer length: *optional* The length of data to replace. All incoming
   data by default.
  :returns: an integer containing the amount of bytes copied or -1.

.. js:function:: HTTPMessage.set_eom(http_msg)

  This function set the end of message for the HTTP message **http_msg**.

  :param class_httpmessage http_msg: The manipulated HTTP message.

.. js:function:: HTTPMessage.set_header(http_msg, name, value)

  This variable replace all occurrence of all header matching the name **name**,
  by only one containing the value **value**.

  :param class_httpmessage http_msg: The manipulated HTTP message.
  :param string name: The header name.
  :param string value: The header value.

  This function does the same work as the following code:

.. code-block:: lua

      http_msg:del_header("header")
      http_msg:add_header("header", "value")
..

.. js:function:: HTTPMessage.set_method(http_msg, method)

  Rewrites the request method with the string **method**. The HTTP message
  **http_msg** must be the request.

  :param class_httpmessage http_msg: The manipulated HTTP message.
  :param string method: The new method.

.. js:function:: HTTPMessage.set_path(http_msg, path)

  Rewrites the request path with the string **path**. The HTTP message
  **http_msg** must be the request.

  :param class_httpmessage http_msg: The manipulated HTTP message.
  :param string method: The new method.

.. js:function:: HTTPMessage.set_query(http_msg, query)

  Rewrites the request's query string which appears after the first question
  mark ("?") with the string **query**. The HTTP message **http_msg** must be
  the request.

  :param class_httpmessage http_msg: The manipulated HTTP message.
  :param string query: The new query.

.. js:function:: HTTPMessage.set_status(http_msg, status[, reason])

  Rewrites the response status code with the integer **code** and optional the
  reason **reason**. If no custom reason is provided, it will be generated from
  the status. The HTTP message **http_msg** must be the response.

  :param class_httpmessage http_msg: The manipulated HTTP message.
  :param integer status: The new response status code.
  :param string reason: The new response reason (optional).

.. js:function:: HTTPMessage.set_uri(http_msg, uri)

  Rewrites the request URI with the string **uri**. The HTTP message
  **http_msg** must be the request.

  :param class_httpmessage http_msg: The manipulated HTTP message.
  :param string uri: The new uri.

.. js:function:: HTTPMessage.unset_eom(http_msg)

  This function remove the end of message for the HTTP message **http_msg**.

  :param class_httpmessage http_msg: The manipulated HTTP message.

.. _CertCache_class:

CertCache class
================

.. js:class:: CertCache

   This class allows to update an SSL certificate file in the memory of the
   current HAProxy process. It will do the same as "set ssl cert" + "commit ssl
   cert" over the HAProxy CLI.

.. js:function:: CertCache.set(certificate)

  This function updates a certificate in memory.

  :param table certificate: A table containing the fields to update.
  :param string certificate.filename: The mandatory filename of the certificate
   to update, it must already exist in memory.
  :param string certificate.crt: A certificate in the PEM format. It can also
   contain a private key.
  :param string certificate.key: A private key in the PEM format.
  :param string certificate.ocsp: An OCSP response in base64. (cf management.txt)
  :param string certificate.issuer: The certificate of the OCSP issuer.
  :param string certificate.sctl: An SCTL file.

.. code-block:: lua

    CertCache.set{filename="certs/localhost9994.pem.rsa", crt=crt}


External Lua libraries
======================

A lot of useful lua libraries can be found here:

* Lua toolbox has been superseded by
  `https://luarocks.org/ <https://luarocks.org/>`_

  The old lua toolbox source code is still available here
  `https://github.com/catwell/lua-toolbox <https://github.com/catwell/lua-toolbox>`_ (DEPRECATED)

Redis client library:

* `https://github.com/nrk/redis-lua <https://github.com/nrk/redis-lua>`_

This is an example about the usage of the Redis library within HAProxy.
Note that each call to any function of this library can throw an error if
the socket connection fails.

.. code-block:: lua

    -- load the redis library
    local redis = require("redis");

    function do_something(txn)

       -- create and connect new tcp socket
       local tcp = core.tcp();
       tcp:settimeout(1);
       tcp:connect("127.0.0.1", 6379);

       -- use the redis library with this new socket
       local client = redis.connect({socket=tcp});
       client:ping();

    end

OpenSSL:

* `http://mkottman.github.io/luacrypto/index.html
  <http://mkottman.github.io/luacrypto/index.html>`_

* `https://github.com/brunoos/luasec/wiki
  <https://github.com/brunoos/luasec/wiki>`_