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
|
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en"><head>
<meta content="text/html; charset=UTF-8" http-equiv="Content-Type" />
<!--
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
This file is generated from xml source: DO NOT EDIT
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
-->
<title>mod_authn_socache - Apache HTTP Server Version 2.4</title>
<link href="../style/css/manual.css" rel="stylesheet" media="all" type="text/css" title="Main stylesheet" />
<link href="../style/css/manual-loose-100pc.css" rel="alternate stylesheet" media="all" type="text/css" title="No Sidebar - Default font size" />
<link href="../style/css/manual-print.css" rel="stylesheet" media="print" type="text/css" /><link rel="stylesheet" type="text/css" href="../style/css/prettify.css" />
<script src="../style/scripts/prettify.min.js" type="text/javascript">
</script>
<link href="../images/favicon.ico" rel="shortcut icon" /></head>
<body>
<div id="page-header">
<p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/directives.html">Directives</a> | <a href="http://wiki.apache.org/httpd/FAQ">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p>
<p class="apache">Apache HTTP Server Version 2.4</p>
<img alt="" src="../images/feather.png" /></div>
<div class="up"><a href="./"><img title="<-" alt="<-" src="../images/left.gif" /></a></div>
<div id="path">
<a href="http://www.apache.org/">Apache</a> > <a href="http://httpd.apache.org/">HTTP Server</a> > <a href="http://httpd.apache.org/docs/">Documentation</a> > <a href="../">Version 2.4</a> > <a href="./">Modules</a></div>
<div id="page-content">
<div id="preamble"><h1>Apache Module mod_authn_socache</h1>
<div class="toplang">
<p><span>Available Languages: </span><a href="../en/mod/mod_authn_socache.html" title="English"> en </a> |
<a href="../fr/mod/mod_authn_socache.html" hreflang="fr" rel="alternate" title="Français"> fr </a></p>
</div>
<table class="module"><tr><th><a href="module-dict.html#Description">Description:</a></th><td>Manages a cache of authentication credentials to relieve
the load on backends</td></tr>
<tr><th><a href="module-dict.html#Status">Status:</a></th><td>Base</td></tr>
<tr><th><a href="module-dict.html#ModuleIdentifier">Module Identifier:</a></th><td>authn_socache_module</td></tr>
<tr><th><a href="module-dict.html#SourceFile">Source File:</a></th><td>mod_authn_socache.c</td></tr>
<tr><th><a href="module-dict.html#Compatibility">Compatibility:</a></th><td>Version 2.3 and later</td></tr></table>
<h3>Summary</h3>
<p>Maintains a cache of authentication credentials, so that a new backend
lookup is not required for every authenticated request.</p>
</div>
<div id="quickview"><a href="https://www.apache.org/foundation/contributing.html" class="badge"><img src="https://www.apache.org/images/SupportApache-small.png" alt="Support Apache!" /></a><h3>Topics</h3>
<ul id="topics">
<li><img alt="" src="../images/down.gif" /> <a href="#intro">Authentication Caching</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#usage">Usage</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#dev">Caching with custom modules</a></li>
</ul><h3 class="directives">Directives</h3>
<ul id="toc">
<li><img alt="" src="../images/down.gif" /> <a href="#authncachecontext">AuthnCacheContext</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#authncacheenable">AuthnCacheEnable</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#authncacheprovidefor">AuthnCacheProvideFor</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#authncachesocache">AuthnCacheSOCache</a></li>
<li><img alt="" src="../images/down.gif" /> <a href="#authncachetimeout">AuthnCacheTimeout</a></li>
</ul>
<h3>Bugfix checklist</h3><ul class="seealso"><li><a href="https://www.apache.org/dist/httpd/CHANGES_2.4">httpd changelog</a></li><li><a href="https://bz.apache.org/bugzilla/buglist.cgi?bug_status=__open__&list_id=144532&product=Apache%20httpd-2&query_format=specific&order=changeddate%20DESC%2Cpriority%2Cbug_severity&component=mod_authn_socache">Known issues</a></li><li><a href="https://bz.apache.org/bugzilla/enter_bug.cgi?product=Apache%20httpd-2&component=mod_authn_socache">Report a bug</a></li></ul><h3>See also</h3>
<ul class="seealso">
<li><a href="#comments_section">Comments</a></li></ul></div>
<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="section">
<h2><a name="intro" id="intro">Authentication Caching</a></h2>
<p>Some users of more heavyweight authentication such as SQL database
lookups (<code class="module"><a href="../mod/mod_authn_dbd.html">mod_authn_dbd</a></code>) have reported it putting an
unacceptable load on their authentication provider. A typical case
in point is where an HTML page contains hundreds of objects
(images, scripts, stylesheets, media, etc), and a request to the page
generates hundreds of effectively-immediate requests for authenticated
additional contents.</p>
<p><code class="module"><a href="../mod/mod_authn_socache.html">mod_authn_socache</a></code> provides a solution to this problem by
maintaining a cache of authentication credentials.</p>
</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="section">
<h2><a name="usage" id="usage">Usage</a></h2>
<p>The authentication cache should be used where authentication
lookups impose a significant load on the server, or a backend or
network. Authentication by file (<code class="module"><a href="../mod/mod_authn_file.html">mod_authn_file</a></code>)
or dbm (<code class="module"><a href="../mod/mod_authn_dbm.html">mod_authn_dbm</a></code>) are unlikely to benefit,
as these are fast and lightweight in their own right (though in some
cases, such as a network-mounted file, caching may be worthwhile).
Other providers such as SQL or LDAP based authentication are more
likely to benefit, particularly where there is an observed
performance issue. Amongst the standard modules, <code class="module"><a href="../mod/mod_authnz_ldap.html">mod_authnz_ldap</a></code> manages its own cache, so only
<code class="module"><a href="../mod/mod_authn_dbd.html">mod_authn_dbd</a></code> will usually benefit from this cache.</p>
<p>The basic rules to cache for a provider are:</p>
<ol><li>Include the provider you're caching for in an
<code class="directive"><a href="#authncacheprovidefor">AuthnCacheProvideFor</a></code> directive.</li>
<li>List <var>socache</var> ahead of the provider you're
caching for in your <code class="directive"><a href="../mod/mod_auth_basic.html#authbasicprovider">AuthBasicProvider</a></code> or <code class="directive"><a href="../mod/mod_auth_digest.html#authdigestprovider">AuthDigestProvider</a></code> directive.</li>
</ol>
<p>A simple usage example to accelerate <code class="module"><a href="../mod/mod_authn_dbd.html">mod_authn_dbd</a></code>
using dbm as a cache engine:</p>
<pre class="prettyprint lang-config">#AuthnCacheSOCache is optional. If specified, it is server-wide
AuthnCacheSOCache dbm
<Directory "/usr/www/myhost/private">
AuthType Basic
AuthName "Cached Authentication Example"
AuthBasicProvider socache dbd
AuthDBDUserPWQuery "SELECT password FROM authn WHERE user = %s"
AuthnCacheProvideFor dbd
Require valid-user
#Optional
AuthnCacheContext dbd-authn-example
</Directory></pre>
</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="section">
<h2><a name="dev" id="dev">Caching with custom modules</a></h2>
<p>Module developers should note that their modules must be enabled
for caching with <code class="module"><a href="../mod/mod_authn_socache.html">mod_authn_socache</a></code>. A single optional API function
<var>ap_authn_cache_store</var> is provided to cache credentials
a provider has just looked up or generated. Usage examples are
available in <a href="http://svn.eu.apache.org/viewvc?view=revision&revision=957072">r957072</a>, in which three authn providers are enabled for caching.</p>
</div>
<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="directive-section"><h2><a name="AuthnCacheContext" id="AuthnCacheContext">AuthnCacheContext</a> <a name="authncachecontext" id="authncachecontext">Directive</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Specify a context string for use in the cache key</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AuthnCacheContext directory|server|<var>custom-string</var></code></td></tr>
<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AuthnCacheContext directory</code></td></tr>
<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory</td></tr>
<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Base</td></tr>
<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_authn_socache</td></tr>
</table>
<p>This directive specifies a string to be used along with the supplied
username (and realm in the case of Digest Authentication) in constructing
a cache key. This serves to disambiguate identical usernames serving
different authentication areas on the server.</p>
<p>Two special values for this are <code>directory</code>, which uses
the directory context of the request as a string, and <code>server</code>
which uses the virtual host name.</p>
<p>The default is <code>directory</code>, which is also the most
conservative setting. This is likely to be less than optimal, as it
(for example) causes <var>$app-base</var>, <var>$app-base/images</var>,
<var>$app-base/scripts</var> and <var>$app-base/media</var> each to
have its own separate cache key. A better policy is to name the
<code class="directive">AuthnCacheContext</code> for the password
provider: for example a <var>htpasswd</var> file or database table.</p>
<p>Contexts can be shared across different areas of a server, where
credentials are shared. However, this has potential to become a vector
for cross-site or cross-application security breaches, so this directive
is not permitted in <var>.htaccess</var> contexts.</p>
</div>
<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="directive-section"><h2><a name="AuthnCacheEnable" id="AuthnCacheEnable">AuthnCacheEnable</a> <a name="authncacheenable" id="authncacheenable">Directive</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enable Authn caching configured anywhere</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AuthnCacheEnable</code></td></tr>
<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Base</td></tr>
<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_authn_socache</td></tr>
</table>
<p>This directive is not normally necessary: it is implied if
authentication caching is enabled anywhere in <var>httpd.conf</var>.
However, if it is not enabled anywhere in <var>httpd.conf</var>
it will by default not be initialised, and is therefore not
available in a <var>.htaccess</var> context. This directive
ensures it is initialised so it can be used in <var>.htaccess</var>.</p>
</div>
<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="directive-section"><h2><a name="AuthnCacheProvideFor" id="AuthnCacheProvideFor">AuthnCacheProvideFor</a> <a name="authncacheprovidefor" id="authncacheprovidefor">Directive</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Specify which authn provider(s) to cache for</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AuthnCacheProvideFor <var>authn-provider</var> [...]</code></td></tr>
<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>None</code></td></tr>
<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
<tr><th><a href="directive-dict.html#Override">Override:</a></th><td>AuthConfig</td></tr>
<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Base</td></tr>
<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_authn_socache</td></tr>
</table>
<p>This directive specifies an authentication provider or providers
to cache for. Credentials found by a provider not listed in an
<code class="directive">AuthnCacheProvideFor</code> directive will not be cached.</p>
<p>For example, to cache credentials found by <code class="module"><a href="../mod/mod_authn_dbd.html">mod_authn_dbd</a></code>
or by a custom provider <var>myprovider</var>, but leave those looked
up by lightweight providers like file or dbm lookup alone:</p>
<pre class="prettyprint lang-config">AuthnCacheProvideFor dbd myprovider</pre>
</div>
<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="directive-section"><h2><a name="AuthnCacheSOCache" id="AuthnCacheSOCache">AuthnCacheSOCache</a> <a name="authncachesocache" id="authncachesocache">Directive</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Select socache backend provider to use</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AuthnCacheSOCache <var>provider-name[:provider-args]</var></code></td></tr>
<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Base</td></tr>
<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_authn_socache</td></tr>
<tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Optional provider arguments are available in
Apache HTTP Server 2.4.7 and later</td></tr>
</table>
<p>This is a server-wide setting to select a provider for the
<a href="../socache.html">shared object cache</a>, followed by
optional arguments for that provider.
Some possible values for <var>provider-name</var> are "dbm", "dc",
"memcache", or "shmcb", each subject to the appropriate module
being loaded. If not set, your platform's default will be used.</p>
</div>
<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div>
<div class="directive-section"><h2><a name="AuthnCacheTimeout" id="AuthnCacheTimeout">AuthnCacheTimeout</a> <a name="authncachetimeout" id="authncachetimeout">Directive</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Set a timeout for cache entries</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AuthnCacheTimeout <var>timeout</var> (seconds)</code></td></tr>
<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AuthnCacheTimeout 300 (5 minutes)</code></td></tr>
<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>directory, .htaccess</td></tr>
<tr><th><a href="directive-dict.html#Override">Override:</a></th><td>AuthConfig</td></tr>
<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Base</td></tr>
<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_authn_socache</td></tr>
</table>
<p>Caching authentication data can be a security issue, though short-term
caching is unlikely to be a problem. Typically a good solution is to
cache credentials for as long as it takes to relieve the load on a
backend, but no longer, though if changes to your users and passwords
are infrequent then a longer timeout may suit you. The default 300
seconds (5 minutes) is both cautious and ample to keep the load
on a backend such as dbd (SQL database queries) down.</p>
<p>This should not be confused with session timeout, which is an
entirely separate issue. However, you may wish to check your
session-management software for whether cached credentials can
"accidentally" extend a session, and bear it in mind when setting
your timeout.</p>
</div>
</div>
<div class="bottomlang">
<p><span>Available Languages: </span><a href="../en/mod/mod_authn_socache.html" title="English"> en </a> |
<a href="../fr/mod/mod_authn_socache.html" hreflang="fr" rel="alternate" title="Français"> fr </a></p>
</div><div class="top"><a href="#page-header"><img src="../images/up.gif" alt="top" /></a></div><div class="section"><h2><a id="comments_section" name="comments_section">Comments</a></h2><div class="warning"><strong>Notice:</strong><br />This is not a Q&A section. Comments placed here should be pointed towards suggestions on improving the documentation or server, and may be removed by our moderators if they are either implemented or considered invalid/off-topic. Questions on how to manage the Apache HTTP Server should be directed at either our IRC channel, #httpd, on Libera.chat, or sent to our <a href="https://httpd.apache.org/lists.html">mailing lists</a>.</div>
<script type="text/javascript"><!--//--><![CDATA[//><!--
var comments_shortname = 'httpd';
var comments_identifier = 'http://httpd.apache.org/docs/2.4/mod/mod_authn_socache.html';
(function(w, d) {
if (w.location.hostname.toLowerCase() == "httpd.apache.org") {
d.write('<div id="comments_thread"><\/div>');
var s = d.createElement('script');
s.type = 'text/javascript';
s.async = true;
s.src = 'https://comments.apache.org/show_comments.lua?site=' + comments_shortname + '&page=' + comments_identifier;
(d.getElementsByTagName('head')[0] || d.getElementsByTagName('body')[0]).appendChild(s);
}
else {
d.write('<div id="comments_thread">Comments are disabled for this page at the moment.<\/div>');
}
})(window, document);
//--><!]]></script></div><div id="footer">
<p class="apache">Copyright 2023 The Apache Software Foundation.<br />Licensed under the <a href="http://www.apache.org/licenses/LICENSE-2.0">Apache License, Version 2.0</a>.</p>
<p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/directives.html">Directives</a> | <a href="http://wiki.apache.org/httpd/FAQ">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p></div><script type="text/javascript"><!--//--><![CDATA[//><!--
if (typeof(prettyPrint) !== 'undefined') {
prettyPrint();
}
//--><!]]></script>
</body></html>
|
