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mod_cache: Check the request to determine whether we are allowed

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to return cached content at all, and respect a "Cache-Control:
no-cache" header from a client. Previously, "no-cache" would
behave like "max-age=0".


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@992625 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Graham Leggett
2010-09-04 15:20:30 +00:00
parent 8991d4795f
commit c3084aa4de
4 changed files with 84 additions and 5 deletions
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70
modules/cache/cache_util.c vendored
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@@ -380,6 +380,64 @@ CACHE_DECLARE(apr_status_t) ap_cache_remove_lock(cache_server_conf *conf,
return apr_file_remove(lockname, r->pool);
}
CACHE_DECLARE(int) ap_cache_check_allowed(request_rec *r) {
const char *cc_cresp, *cc_req;
const char *pragma;
cache_server_conf *conf =
(cache_server_conf *)ap_get_module_config(r->server->module_config,
&cache_module);
/*
* At this point, we may have data cached, but the request may have
* specified that cached data may not be used in a response.
*
* This is covered under RFC2616 section 14.9.4 (Cache Revalidation and
* Reload Controls).
*
* - RFC2616 14.9.4 End to end reload, Cache-Control: no-cache, or Pragma:
* no-cache. The server MUST NOT use a cached copy when responding to such
* a request.
*
* - RFC2616 14.9.2 What May be Stored by Caches. If Cache-Control:
* no-store arrives, do not serve from the cache.
*/
/* This value comes from the client's initial request. */
cc_req = apr_table_get(r->headers_in, "Cache-Control");
pragma = apr_table_get(r->headers_in, "Pragma");
if (ap_cache_liststr(NULL, pragma, "no-cache", NULL)
|| ap_cache_liststr(NULL, cc_req, "no-cache", NULL)) {
if (!conf->ignorecachecontrol) {
return 0;
}
else {
ap_log_error(APLOG_MARK, APLOG_INFO, 0, r->server,
"Incoming request is asking for an uncached version of "
"%s, but we have been configured to ignore it and serve "
"cached content anyway", r->unparsed_uri);
}
}
if (ap_cache_liststr(NULL, cc_req, "no-store", NULL)) {
if (!conf->ignorecachecontrol) {
/* We're not allowed to serve a cached copy */
return 0;
}
else {
ap_log_error(APLOG_MARK, APLOG_INFO, 0, r->server,
"Incoming request is asking for a no-store version of "
"%s, but we have been configured to ignore it and serve "
"cached content anyway", r->unparsed_uri);
}
}
return 1;
}
CACHE_DECLARE(int) ap_cache_check_freshness(cache_handle_t *h,
request_rec *r)
{
@@ -402,10 +460,11 @@ CACHE_DECLARE(int) ap_cache_check_freshness(cache_handle_t *h,
* We now want to check if our cached data is still fresh. This depends
* on a few things, in this order:
*
* - RFC2616 14.9.4 End to end reload, Cache-Control: no-cache. no-cache in
* either the request or the cached response means that we must
* revalidate the request unconditionally, overriding any expiration
* mechanism. It's equivalent to max-age=0,must-revalidate.
* - RFC2616 14.9.4 End to end reload, Cache-Control: no-cache. no-cache
* in either the request or the cached response means that we must
* perform the request unconditionally, and ignore cached content. We
* should never reach here, but if we do, mark the content as stale,
* as this is the best we can do.
*
* - RFC2616 14.32 Pragma: no-cache This is treated the same as
* Cache-Control: no-cache.
@@ -445,7 +504,8 @@ CACHE_DECLARE(int) ap_cache_check_freshness(cache_handle_t *h,
ap_log_error(APLOG_MARK, APLOG_INFO, 0, r->server,
"Incoming request is asking for a uncached version of "
"%s, but we know better and are ignoring it",
"%s, but we have been configured to ignore it and "
"serve a cached response anyway",
r->unparsed_uri);
}