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+/* Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * mod_expires.c
+ * version 0.0.11
+ * status beta
+ *
+ * Andrew Wilson <Andrew.Wilson@cm.cf.ac.uk> 26.Jan.96
+ *
+ * This module allows you to control the form of the Expires: header
+ * that Apache issues for each access. Directives can appear in
+ * configuration files or in .htaccess files so expiry semantics can
+ * be defined on a per-directory basis.
+ *
+ * DIRECTIVE SYNTAX
+ *
+ * Valid directives are:
+ *
+ * ExpiresActive on | off
+ * ExpiresDefault <code><seconds>
+ * ExpiresByType type/encoding <code><seconds>
+ *
+ * Valid values for <code> are:
+ *
+ * 'M' expires header shows file modification date + <seconds>
+ * 'A' expires header shows access time + <seconds>
+ *
+ * [I'm not sure which of these is best under different
+ * circumstances, I guess it's for other people to explore.
+ * The effects may be indistinguishable for a number of cases]
+ *
+ * <seconds> should be an integer value [acceptable to atoi()]
+ *
+ * There is NO space between the <code> and <seconds>.
+ *
+ * For example, a directory which contains information which changes
+ * frequently might contain:
+ *
+ * # reports generated by cron every hour. don't let caches
+ * # hold onto stale information
+ * ExpiresDefault M3600
+ *
+ * Another example, our html pages can change all the time, the gifs
+ * tend not to change often:
+ *
+ * # pages are hot (1 week), images are cold (1 month)
+ * ExpiresByType text/html A604800
+ * ExpiresByType image/gif A2592000
+ *
+ * Expires can be turned on for all URLs on the server by placing the
+ * following directive in a conf file:
+ *
+ * ExpiresActive on
+ *
+ * ExpiresActive can also appear in .htaccess files, enabling the
+ * behaviour to be turned on or off for each chosen directory.
+ *
+ * # turn off Expires behaviour in this directory
+ * # and subdirectories
+ * ExpiresActive off
+ *
+ * Directives defined for a directory are valid in subdirectories
+ * unless explicitly overridden by new directives in the subdirectory
+ * .htaccess files.
+ *
+ * ALTERNATIVE DIRECTIVE SYNTAX
+ *
+ * Directives can also be defined in a more readable syntax of the form:
+ *
+ * ExpiresDefault "<base> [plus] {<num> <type>}*"
+ * ExpiresByType type/encoding "<base> [plus] {<num> <type>}*"
+ *
+ * where <base> is one of:
+ * access
+ * now equivalent to 'access'
+ * modification
+ *
+ * where the 'plus' keyword is optional
+ *
+ * where <num> should be an integer value [acceptable to atoi()]
+ *
+ * where <type> is one of:
+ * years
+ * months
+ * weeks
+ * days
+ * hours
+ * minutes
+ * seconds
+ *
+ * For example, any of the following directives can be used to make
+ * documents expire 1 month after being accessed, by default:
+ *
+ * ExpiresDefault "access plus 1 month"
+ * ExpiresDefault "access plus 4 weeks"
+ * ExpiresDefault "access plus 30 days"
+ *
+ * The expiry time can be fine-tuned by adding several '<num> <type>'
+ * clauses:
+ *
+ * ExpiresByType text/html "access plus 1 month 15 days 2 hours"
+ * ExpiresByType image/gif "modification plus 5 hours 3 minutes"
+ *
+ * ---
+ *
+ * Change-log:
+ * 29.Jan.96 Hardened the add_* functions. Server will now bail out
+ * if bad directives are given in the conf files.
+ * 02.Feb.96 Returns DECLINED if not 'ExpiresActive on', giving other
+ * expires-aware modules a chance to play with the same
+ * directives. [Michael Rutman]
+ * 03.Feb.96 Call tzset() before localtime(). Trying to get the module
+ * to work properly in non GMT timezones.
+ * 12.Feb.96 Modified directive syntax to allow more readable commands:
+ * ExpiresDefault "now plus 10 days 20 seconds"
+ * ExpiresDefault "access plus 30 days"
+ * ExpiresDefault "modification plus 1 year 10 months 30 days"
+ * 13.Feb.96 Fix call to table_get() with NULL 2nd parameter [Rob Hartill]
+ * 19.Feb.96 Call gm_timestr_822() to get time formatted correctly, can't
+ * rely on presence of HTTP_TIME_FORMAT in Apache 1.1+.
+ * 21.Feb.96 This version (0.0.9) reverses assumptions made in 0.0.8
+ * about star/star handlers. Reverting to 0.0.7 behaviour.
+ * 08.Jun.96 allows ExpiresDefault to be used with responses that use
+ * the DefaultType by not DECLINING, but instead skipping
+ * the table_get check and then looking for an ExpiresDefault.
+ * [Rob Hartill]
+ * 04.Nov.96 'const' definitions added.
+ *
+ * TODO
+ * add support for Cache-Control: max-age=20 from the HTTP/1.1
+ * proposal (in this case, a ttl of 20 seconds) [ask roy]
+ * add per-file expiry and explicit expiry times - duplicates some
+ * of the mod_cern_meta.c functionality. eg:
+ * ExpiresExplicit index.html "modification plus 30 days"
+ *
+ * BUGS
+ * Hi, welcome to the internet.
+ */
+
+#include "apr.h"
+#include "apr_strings.h"
+#include "apr_lib.h"
+
+#define APR_WANT_STRFUNC
+#include "apr_want.h"
+
+#include "ap_config.h"
+#include "httpd.h"
+#include "http_config.h"
+#include "http_log.h"
+#include "http_request.h"
+#include "http_protocol.h"
+
+typedef struct {
+ int active;
+ int wildcards;
+ char *expiresdefault;
+ apr_table_t *expiresbytype;
+} expires_dir_config;
+
+/* from mod_dir, why is this alias used?
+ */
+#define DIR_CMD_PERMS OR_INDEXES
+
+#define ACTIVE_ON 1
+#define ACTIVE_OFF 0
+#define ACTIVE_DONTCARE 2
+
+module AP_MODULE_DECLARE_DATA expires_module;
+
+static void *create_dir_expires_config(apr_pool_t *p, char *dummy)
+{
+ expires_dir_config *new =
+ (expires_dir_config *) apr_pcalloc(p, sizeof(expires_dir_config));
+ new->active = ACTIVE_DONTCARE;
+ new->wildcards = 0;
+ new->expiresdefault = NULL;
+ new->expiresbytype = apr_table_make(p, 4);
+ return (void *) new;
+}
+
+static const char *set_expiresactive(cmd_parms *cmd, void *in_dir_config, int arg)
+{
+ expires_dir_config *dir_config = in_dir_config;
+
+ /* if we're here at all it's because someone explicitly
+ * set the active flag
+ */
+ dir_config->active = ACTIVE_ON;
+ if (arg == 0) {
+ dir_config->active = ACTIVE_OFF;
+ }
+ return NULL;
+}
+
+/* check_code() parse 'code' and return NULL or an error response
+ * string. If we return NULL then real_code contains code converted
+ * to the cnnnn format.
+ */
+static char *check_code(apr_pool_t *p, const char *code, char **real_code)
+{
+ char *word;
+ char base = 'X';
+ int modifier = 0;
+ int num = 0;
+ int factor;
+
+ /* 0.0.4 compatibility?
+ */
+ if ((code[0] == 'A') || (code[0] == 'M')) {
+ *real_code = (char *)code;
+ return NULL;
+ }
+
+ /* <base> [plus] {<num> <type>}*
+ */
+
+ /* <base>
+ */
+ word = ap_getword_conf(p, &code);
+ if (!strncasecmp(word, "now", 1) ||
+ !strncasecmp(word, "access", 1)) {
+ base = 'A';
+ }
+ else if (!strncasecmp(word, "modification", 1)) {
+ base = 'M';
+ }
+ else {
+ return apr_pstrcat(p, "bad expires code, unrecognised <base> '",
+ word, "'", NULL);
+ }
+
+ /* [plus]
+ */
+ word = ap_getword_conf(p, &code);
+ if (!strncasecmp(word, "plus", 1)) {
+ word = ap_getword_conf(p, &code);
+ }
+
+ /* {<num> <type>}*
+ */
+ while (word[0]) {
+ /* <num>
+ */
+ if (apr_isdigit(word[0])) {
+ num = atoi(word);
+ }
+ else {
+ return apr_pstrcat(p, "bad expires code, numeric value expected <num> '",
+ word, "'", NULL);
+ }
+
+ /* <type>
+ */
+ word = ap_getword_conf(p, &code);
+ if (word[0] == '\0') {
+ return apr_pstrcat(p, "bad expires code, missing <type>", NULL);
+ }
+
+ if (!strncasecmp(word, "years", 1)) {
+ factor = 60 * 60 * 24 * 365;
+ }
+ else if (!strncasecmp(word, "months", 2)) {
+ factor = 60 * 60 * 24 * 30;
+ }
+ else if (!strncasecmp(word, "weeks", 1)) {
+ factor = 60 * 60 * 24 * 7;
+ }
+ else if (!strncasecmp(word, "days", 1)) {
+ factor = 60 * 60 * 24;
+ }
+ else if (!strncasecmp(word, "hours", 1)) {
+ factor = 60 * 60;
+ }
+ else if (!strncasecmp(word, "minutes", 2)) {
+ factor = 60;
+ }
+ else if (!strncasecmp(word, "seconds", 1)) {
+ factor = 1;
+ }
+ else {
+ return apr_pstrcat(p, "bad expires code, unrecognised <type>",
+ "'", word, "'", NULL);
+ }
+
+ modifier = modifier + factor * num;
+
+ /* next <num>
+ */
+ word = ap_getword_conf(p, &code);
+ }
+
+ *real_code = apr_psprintf(p, "%c%d", base, modifier);
+
+ return NULL;
+}
+
+static const char *set_expiresbytype(cmd_parms *cmd, void *in_dir_config,
+ const char *mime, const char *code)
+{
+ expires_dir_config *dir_config = in_dir_config;
+ char *response, *real_code;
+ const char *check;
+
+ check = ap_strrchr_c(mime, '/');
+ if (check == NULL) {
+ return "Invalid mimetype: should contain a slash";
+ }
+ if ((strlen(++check) == 1) && (*check == '*')) {
+ dir_config->wildcards = 1;
+ }
+
+ if ((response = check_code(cmd->pool, code, &real_code)) == NULL) {
+ apr_table_setn(dir_config->expiresbytype, mime, real_code);
+ return NULL;
+ }
+ return apr_pstrcat(cmd->pool,
+ "'ExpiresByType ", mime, " ", code, "': ", response, NULL);
+}
+
+static const char *set_expiresdefault(cmd_parms *cmd, void *in_dir_config,
+ const char *code)
+{
+ expires_dir_config * dir_config = in_dir_config;
+ char *response, *real_code;
+
+ if ((response = check_code(cmd->pool, code, &real_code)) == NULL) {
+ dir_config->expiresdefault = real_code;
+ return NULL;
+ }
+ return apr_pstrcat(cmd->pool,
+ "'ExpiresDefault ", code, "': ", response, NULL);
+}
+
+static const command_rec expires_cmds[] =
+{
+ AP_INIT_FLAG("ExpiresActive", set_expiresactive, NULL, DIR_CMD_PERMS,
+ "Limited to 'on' or 'off'"),
+ AP_INIT_TAKE2("ExpiresByType", set_expiresbytype, NULL, DIR_CMD_PERMS,
+ "a MIME type followed by an expiry date code"),
+ AP_INIT_TAKE1("ExpiresDefault", set_expiresdefault, NULL, DIR_CMD_PERMS,
+ "an expiry date code"),
+ {NULL}
+};
+
+static void *merge_expires_dir_configs(apr_pool_t *p, void *basev, void *addv)
+{
+ expires_dir_config *new = (expires_dir_config *) apr_pcalloc(p, sizeof(expires_dir_config));
+ expires_dir_config *base = (expires_dir_config *) basev;
+ expires_dir_config *add = (expires_dir_config *) addv;
+
+ if (add->active == ACTIVE_DONTCARE) {
+ new->active = base->active;
+ }
+ else {
+ new->active = add->active;
+ }
+
+ if (add->expiresdefault != NULL) {
+ new->expiresdefault = add->expiresdefault;
+ }
+ else {
+ new->expiresdefault = base->expiresdefault;
+ }
+ new->wildcards = add->wildcards;
+ new->expiresbytype = apr_table_overlay(p, add->expiresbytype,
+ base->expiresbytype);
+ return new;
+}
+
+/*
+ * Handle the setting of the expiration response header fields according
+ * to our criteria.
+ */
+
+static int set_expiration_fields(request_rec *r, const char *code,
+ apr_table_t *t)
+{
+ apr_time_t base;
+ apr_time_t additional;
+ apr_time_t expires;
+ int additional_sec;
+ char *timestr;
+
+ switch (code[0]) {
+ case 'M':
+ if (r->finfo.filetype == APR_NOFILE) {
+ /* file doesn't exist on disk, so we can't do anything based on
+ * modification time. Note that this does _not_ log an error.
+ */
+ return DECLINED;
+ }
+ base = r->finfo.mtime;
+ additional_sec = atoi(&code[1]);
+ additional = apr_time_from_sec(additional_sec);
+ break;
+ case 'A':
+ /* there's been some discussion and it's possible that
+ * 'access time' will be stored in request structure
+ */
+ base = r->request_time;
+ additional_sec = atoi(&code[1]);
+ additional = apr_time_from_sec(additional_sec);
+ break;
+ default:
+ /* expecting the add_* routines to be case-hardened this
+ * is just a reminder that module is beta
+ */
+ ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(01500)
+ "internal error: bad expires code: %s", r->filename);
+ return HTTP_INTERNAL_SERVER_ERROR;
+ }
+
+ expires = base + additional;
+ if (expires < r->request_time) {
+ expires = r->request_time;
+ }
+ apr_table_mergen(t, "Cache-Control",
+ apr_psprintf(r->pool, "max-age=%" APR_TIME_T_FMT,
+ apr_time_sec(expires - r->request_time)));
+ timestr = apr_palloc(r->pool, APR_RFC822_DATE_LEN);
+ apr_rfc822_date(timestr, expires);
+ apr_table_setn(t, "Expires", timestr);
+ return OK;
+}
+
+/*
+ * Output filter to set the Expires response header field
+ * according to the content-type of the response -- if it hasn't
+ * already been set.
+ */
+static apr_status_t expires_filter(ap_filter_t *f,
+ apr_bucket_brigade *b)
+{
+ request_rec *r;
+ expires_dir_config *conf;
+ const char *expiry;
+ apr_table_t *t;
+
+ /* Don't add Expires headers to errors */
+ if (ap_is_HTTP_ERROR(f->r->status)) {
+ ap_remove_output_filter(f);
+ return ap_pass_brigade(f->next, b);
+ }
+
+ r = f->r;
+ conf = (expires_dir_config *) ap_get_module_config(r->per_dir_config,
+ &expires_module);
+
+ /*
+ * Check to see which output header table we should use;
+ * mod_cgi loads script fields into r->err_headers_out,
+ * for instance.
+ */
+ expiry = apr_table_get(r->err_headers_out, "Expires");
+ if (expiry != NULL) {
+ t = r->err_headers_out;
+ }
+ else {
+ expiry = apr_table_get(r->headers_out, "Expires");
+ t = r->headers_out;
+ }
+ if (expiry == NULL) {
+ /*
+ * No expiration has been set, so we can apply any managed by
+ * this module. First, check to see if there is an applicable
+ * ExpiresByType directive.
+ */
+ expiry = apr_table_get(conf->expiresbytype,
+ ap_field_noparam(r->pool, r->content_type));
+ if (expiry == NULL) {
+ int usedefault = 1;
+ /*
+ * See if we have a wildcard entry for the major type.
+ */
+ if (conf->wildcards) {
+ char *checkmime;
+ char *spos;
+ checkmime = apr_pstrdup(r->pool, r->content_type);
+ spos = checkmime ? ap_strchr(checkmime, '/') : NULL;
+ if (spos != NULL) {
+ /*
+ * Without a '/' character, nothing we have will match.
+ * However, we have one.
+ */
+ if (strlen(++spos) > 0) {
+ *spos++ = '*';
+ *spos = '\0';
+ }
+ else {
+ checkmime = apr_pstrcat(r->pool, checkmime, "*", NULL);
+ }
+ expiry = apr_table_get(conf->expiresbytype, checkmime);
+ usedefault = (expiry == NULL);
+ }
+ }
+ if (usedefault) {
+ /*
+ * Use the ExpiresDefault directive
+ */
+ expiry = conf->expiresdefault;
+ }
+ }
+ if (expiry != NULL) {
+ set_expiration_fields(r, expiry, t);
+ }
+ }
+ ap_remove_output_filter(f);
+ return ap_pass_brigade(f->next, b);
+}
+
+static void expires_insert_filter(request_rec *r)
+{
+ expires_dir_config *conf;
+
+ /* Don't add Expires headers to errors */
+ if (ap_is_HTTP_ERROR(r->status)) {
+ return;
+ }
+ /* Say no to subrequests */
+ if (r->main != NULL) {
+ return;
+ }
+ conf = (expires_dir_config *) ap_get_module_config(r->per_dir_config,
+ &expires_module);
+
+ /* Check to see if the filter is enabled and if there are any applicable
+ * config directives for this directory scope
+ */
+ if (conf->active != ACTIVE_ON ||
+ (apr_is_empty_table(conf->expiresbytype) && !conf->expiresdefault)) {
+ return;
+ }
+ ap_add_output_filter("MOD_EXPIRES", NULL, r, r->connection);
+}
+
+static void register_hooks(apr_pool_t *p)
+{
+ /* mod_expires needs to run *before* the cache save filter which is
+ * AP_FTYPE_CONTENT_SET-1. Otherwise, our expires won't be honored.
+ */
+ ap_register_output_filter("MOD_EXPIRES", expires_filter, NULL,
+ AP_FTYPE_CONTENT_SET-2);
+ ap_hook_insert_error_filter(expires_insert_filter, NULL, NULL, APR_HOOK_MIDDLE);
+ ap_hook_insert_filter(expires_insert_filter, NULL, NULL, APR_HOOK_MIDDLE);
+}
+
+AP_DECLARE_MODULE(expires) =
+{
+ STANDARD20_MODULE_STUFF,
+ create_dir_expires_config, /* dir config creater */
+ merge_expires_dir_configs, /* dir merger --- default is to override */
+ NULL, /* server config */
+ NULL, /* merge server configs */
+ expires_cmds, /* command apr_table_t */
+ register_hooks /* register hooks */
+};
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