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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);
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);
}
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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