/* 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; /* 0.0.4 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]) { /* do nothing */ } else { return apr_pstrcat(p, "bad expires code, missing <type>", NULL); } factor = 0; 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 == 0) { /* 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, "internal error: bad expires code: %s", r->filename); return HTTP_INTERNAL_SERVER_ERROR; } expires = base + additional; 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; 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); return; } 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); } module AP_MODULE_DECLARE_DATA expires_module = { 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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