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*
* At this point we decide based on the response headers whether it
* is appropriate _NOT_ to cache the data from the server. There are
* a whole lot of conditions that prevent us from caching this data.
* They are tested here one by one to be clear and unambiguous.
*/
if (r->status != HTTP_OK && r->status != HTTP_NON_AUTHORITATIVE
&& r->status != HTTP_PARTIAL_CONTENT
&& r->status != HTTP_MULTIPLE_CHOICES
&& r->status != HTTP_MOVED_PERMANENTLY
&& r->status != HTTP_NOT_MODIFIED) {
/* RFC2616 13.4 we are allowed to cache 200, 203, 206, 300, 301 or 410
* We allow the caching of 206, but a cache implementation might choose
* to decline to cache a 206 if it doesn't know how to.
* We include 304 Not Modified here too as this is the origin server
* telling us to serve the cached copy.
*/
if (exps != NULL || cc_out != NULL) {
/* We are also allowed to cache any response given that it has a
* valid Expires or Cache Control header. If we find a either of
* those here, we pass request through the rest of the tests. From
* the RFC:
*
* A response received with any other status code (e.g. status
* codes 302 and 307) MUST NOT be returned in a reply to a
* subsequent request unless there are cache-control directives or
* another header(s) that explicitly allow it. For example, these
* include the following: an Expires header (section 14.21); a
* "max-age", "s-maxage", "must-revalidate", "proxy-revalidate",
* "public" or "private" cache-control directive (section 14.9).
*
* FIXME: Wrong if cc_out has just an extension we don't know about
*/
}
else {
reason = apr_psprintf(p, "Response status %d", r->status);
}
}
if (reason) {
/* noop */
}
else if (exps != NULL && exp == APR_DATE_BAD) {
/* if a broken Expires header is present, don't cache it */
reason = apr_pstrcat(p, "Broken expires header: ", exps, NULL);
}
else if (!control.s_maxage && !control.max_age
&& !dconf->store_expired && exp != APR_DATE_BAD
&& exp < r->request_time) {
/* if a Expires header is in the past, don't cache it
* Unless CC: s-maxage or max-age is present
*/
reason = "Expires header already expired; not cacheable";
}
else if (!dconf->store_expired && (control.must_revalidate
|| control.proxy_revalidate) && (!control.s_maxage_value
|| (!control.s_maxage && !control.max_age_value)) && lastmods
== NULL && etag == NULL) {
/* if we're already stale, but can never revalidate, don't cache it */
reason
= "s-maxage or max-age zero and no Last-Modified or Etag; not cacheable";
}
else if (!conf->ignorequerystring && query && exps == NULL
&& !control.max_age && !control.s_maxage) {
/* if a query string is present but no explicit expiration time,
* don't cache it (RFC 2616/13.9 & 13.2.1)
*/
reason = "Query string present but no explicit expiration time";
}
else if (r->status == HTTP_NOT_MODIFIED &&
!cache->handle && !cache->stale_handle) {
/* if the server said 304 Not Modified but we have no cache
* file - pass this untouched to the user agent, it's not for us.
*/
reason = "HTTP Status 304 Not Modified";
}
else if (r->status == HTTP_OK && lastmods == NULL && etag == NULL && (exps
== NULL) && (dconf->no_last_mod_ignore == 0) && !control.max_age
&& !control.s_maxage) {
/* 200 OK response from HTTP/1.0 and up without Last-Modified,
* Etag, Expires, Cache-Control:max-age, or Cache-Control:s-maxage
* headers.
*/
/* Note: mod-include clears last_modified/expires/etags - this
* is why we have an optional function for a key-gen ;-)
*/
reason = "No Last-Modified; Etag; Expires; Cache-Control:max-age or Cache-Control:s-maxage headers";
}
else if (!dconf->store_nostore && control.no_store) {
/* RFC2616 14.9.2 Cache-Control: no-store response
* indicating do not cache, or stop now if you are
* trying to cache it.
*/
reason = "Cache-Control: no-store present";
}
else if (!dconf->store_private && control.private) {
/* RFC2616 14.9.1 Cache-Control: private response
* this object is marked for this user's eyes only. Behave
* as a tunnel.
*/
reason = "Cache-Control: private present";
}
else if (apr_table_get(r->headers_in, "Authorization")
&& !(control.s_maxage || control.must_revalidate
|| control.proxy_revalidate || control.public)) {
/* RFC2616 14.8 Authorisation:
* if authorisation is included in the request, we don't cache,
* but we can cache if the following exceptions are true:
* 1) If Cache-Control: s-maxage is included
* 2) If Cache-Control: must-revalidate is included
* 3) If Cache-Control: public is included
*/
reason = "Authorization required";
}
else if (ap_find_token(NULL, apr_table_get(r->headers_out, "Vary"), "*")) {
reason = "Vary header contains '*'";
}
else if (apr_table_get(r->subprocess_env, "no-cache") != NULL) {
reason = "environment variable 'no-cache' is set";
}
else if (r->no_cache) {
/* or we've been asked not to cache it above */
reason = "r->no_cache present";
}
else if (cache->stale_handle
&& APR_DATE_BAD
!= (date = apr_date_parse_http(
apr_table_get(r->headers_out, "Date")))
&& date < cache->stale_handle->cache_obj->info.date) {
/**
* 13.12 Cache Replacement:
*
* Note: a new response that has an older Date header value than
* existing cached responses is not cacheable.
*/
reason = "updated entity is older than cached entity";
/* while this response is not cacheable, the previous response still is */
ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(02474)
"cache: Removing CACHE_REMOVE_URL filter.");
ap_remove_output_filter(cache->remove_url_filter);
}
else if (r->status == HTTP_NOT_MODIFIED && cache->stale_handle) {
apr_table_t *left = cache->stale_handle->resp_hdrs;
apr_table_t *right = r->headers_out;
const char *ehs = NULL;
/* and lastly, contradiction checks for revalidated responses
* as per RFC2616 Section 10.3.5
*/
if (cache_header_cmp(r->pool, left, right, "ETag")) {
ehs = "ETag";
}
for (eh = MOD_CACHE_ENTITY_HEADERS; *eh; ++eh) {
if (cache_header_cmp(r->pool, left, right, *eh)) {
ehs = (ehs) ? apr_pstrcat(r->pool, ehs, ", ", *eh, NULL) : *eh;
}
}
if (ehs) {
reason = apr_pstrcat(r->pool, "contradiction: 304 Not Modified; "
"but ", ehs, " modified", NULL);
}
}
/**
* Enforce RFC2616 Section 10.3.5, just in case. We caught any
* inconsistencies above.
*
* If the conditional GET used a strong cache validator (see section
* 13.3.3), the response SHOULD NOT include other entity-headers.
* Otherwise (i.e., the conditional GET used a weak validator), the
* response MUST NOT include other entity-headers; this prevents
* inconsistencies between cached entity-bodies and updated headers.
*/
if (r->status == HTTP_NOT_MODIFIED) {
for (eh = MOD_CACHE_ENTITY_HEADERS; *eh; ++eh) {
apr_table_unset(r->headers_out, *eh);
}
}
/* Hold the phone. Some servers might allow us to cache a 2xx, but
* then make their 304 responses non cacheable. RFC2616 says this:
*
* If a 304 response indicates an entity not currently cached, then
* the cache MUST disregard the response and repeat the request
* without the conditional.
*
* A 304 response with contradictory headers is technically a
* different entity, to be safe, we remove the entity from the cache.
*/
if (reason && r->status == HTTP_NOT_MODIFIED && cache->stale_handle) {
ap_log_rerror(APLOG_MARK, APLOG_INFO, 0, r, APLOGNO(02473)
"cache: %s responded with an uncacheable 304, "
"retrying the request %s. Reason: %s",
cache->key, r->unparsed_uri, reason);
/* we've got a cache conditional miss! tell anyone who cares */
cache_run_cache_status(cache->handle, r, r->headers_out, AP_CACHE_MISS,
apr_psprintf(r->pool,
"conditional cache miss: 304 was uncacheable, entity removed: %s",
reason));
/* remove the cached entity immediately, we might cache it again */
ap_remove_output_filter(cache->remove_url_filter);
cache_remove_url(cache, r);
/* let someone else attempt to cache */
cache_remove_lock(conf, cache, r, NULL);
/* remove this filter from the chain */
ap_remove_output_filter(f);
/* retry without the conditionals */
apr_table_unset(r->headers_in, "If-Match");
apr_table_unset(r->headers_in, "If-Modified-Since");
apr_table_unset(r->headers_in, "If-None-Match");
apr_table_unset(r->headers_in, "If-Range");
apr_table_unset(r->headers_in, "If-Unmodified-Since");
/* Currently HTTP_NOT_MODIFIED, and after the redirect, handlers won't think to set status to HTTP_OK */
r->status = HTTP_OK;
ap_internal_redirect(r->unparsed_uri, r);
return APR_SUCCESS;
}
if (reason) {
ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(00768)
"cache: %s not cached for request %s. Reason: %s",
cache->key, r->unparsed_uri, reason);
/* we've got a cache miss! tell anyone who cares */
cache_run_cache_status(cache->handle, r, r->headers_out, AP_CACHE_MISS,
reason);
/* remove this filter from the chain */
ap_remove_output_filter(f);
/* remove the lock file unconditionally */
cache_remove_lock(conf, cache, r, NULL);
/* ship the data up the stack */
return ap_pass_brigade(f->next, in);
}
/* Make it so that we don't execute this path again. */
cache->in_checked = 1;
/* Set the content length if known.
*/
cl = apr_table_get(r->err_headers_out, "Content-Length");
if (cl == NULL) {
cl = apr_table_get(r->headers_out, "Content-Length");
}
if (cl) {
char *errp;
if (apr_strtoff(&size, cl, &errp, 10) || *errp || size < 0) {
cl = NULL; /* parse error, see next 'if' block */
}
}
if (!cl) {
/* if we don't get the content-length, see if we have all the
* buckets and use their length to calculate the size
*/
int all_buckets_here=0;
size=0;
for (e = APR_BRIGADE_FIRST(in);
e != APR_BRIGADE_SENTINEL(in);
e = APR_BUCKET_NEXT(e))
{
if (APR_BUCKET_IS_EOS(e)) {
all_buckets_here=1;
break;
}
if (APR_BUCKET_IS_FLUSH(e)) {
continue;
}
if (e->length == (apr_size_t)-1) {
break;
}
size += e->length;
}
if (!all_buckets_here) {
size = -1;
}
}
/* remember content length to check response size against later */
cache->size = size;
/* It's safe to cache the response.
*
* There are two possibilities at this point:
* - cache->handle == NULL. In this case there is no previously
* cached entity anywhere on the system. We must create a brand
* new entity and store the response in it.
* - cache->stale_handle != NULL. In this case there is a stale
* entity in the system which needs to be replaced by new
* content (unless the result was 304 Not Modified, which means
* the cached entity is actually fresh, and we should update
* the headers).
*/
/* Did we have a stale cache entry that really is stale?
*/
if (cache->stale_handle) {
if (r->status == HTTP_NOT_MODIFIED) {
/* Oh, hey. It isn't that stale! Yay! */
cache->handle = cache->stale_handle;
info = &cache->handle->cache_obj->info;
rv = OK;
}
else {
/* Oh, well. Toss it. */
cache->provider->remove_entity(cache->stale_handle);
/* Treat the request as if it wasn't conditional. */
cache->stale_handle = NULL;
/*
* Restore the original request headers as they may be needed
* by further output filters like the byterange filter to make
* the correct decisions.
*/
r->headers_in = cache->stale_headers;
}
}
/* no cache handle, create a new entity */
if (!cache->handle) {
rv = cache_create_entity(cache, r, size, in);
info = apr_pcalloc(r->pool, sizeof(cache_info));
/* We only set info->status upon the initial creation. */
info->status = r->status;
}
if (rv != OK) {
/* we've got a cache miss! tell anyone who cares */
cache_run_cache_status(cache->handle, r, r->headers_out, AP_CACHE_MISS,
"cache miss: cache unwilling to store response");
/* Caching layer declined the opportunity to cache the response */
ap_remove_output_filter(f);
cache_remove_lock(conf, cache, r, NULL);
return ap_pass_brigade(f->next, in);
}
ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(00769)
"cache: Caching url %s for request %s",
cache->key, r->unparsed_uri);
/* We are actually caching this response. So it does not
* make sense to remove this entity any more.
*/
ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(00770)
"cache: Removing CACHE_REMOVE_URL filter.");
ap_remove_output_filter(cache->remove_url_filter);
/*
* We now want to update the cache file header information with
* the new date, last modified, expire and content length and write
* it away to our cache file. First, we determine these values from
* the response, using heuristics if appropriate.
*
* In addition, we make HTTP/1.1 age calculations and write them away
* too.
*/
/* store away the previously parsed cache control headers */
memcpy(&info->control, &control, sizeof(cache_control_t));
/* Read the date. Generate one if one is not supplied */
dates = apr_table_get(r->err_headers_out, "Date");
if (dates == NULL) {
dates = apr_table_get(r->headers_out, "Date");
}
if (dates != NULL) {
info->date = apr_date_parse_http(dates);
}
else {
info->date = APR_DATE_BAD;
}
now = apr_time_now();
if (info->date == APR_DATE_BAD) { /* No, or bad date */
/* no date header (or bad header)! */
info->date = now;
}
date = info->date;
/* set response_time for HTTP/1.1 age calculations */
info->response_time = now;
/* get the request time */
info->request_time = r->request_time;
/* check last-modified date */
if (lastmod != APR_DATE_BAD && lastmod > date) {
/* if it's in the future, then replace by date */
lastmod = date;
ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0,
r, APLOGNO(00771) "cache: Last modified is in the future, "
"replacing with now");
}
/* CC has priority over Expires. */
if (control.s_maxage || control.max_age) {
apr_int64_t x;
x = control.s_maxage ? control.s_maxage_value : control.max_age_value;
x = x * MSEC_ONE_SEC;
if (x < dconf->minex) {
x = dconf->minex;
}
if (x > dconf->maxex) {
x = dconf->maxex;
}
exp = date + x;
}
/* if no expiry date then
* if Cache-Control: s-maxage
* expiry date = date + smaxage
* if Cache-Control: max-age
* expiry date = date + max-age
* else if lastmod
* expiry date = date + min((date - lastmod) * factor, maxexpire)
* else
* expire date = date + defaultexpire
*/
if (exp == APR_DATE_BAD) {
if ((lastmod != APR_DATE_BAD) && (lastmod < date)) {
/* if lastmod == date then you get 0*conf->factor which results in
* an expiration time of now. This causes some problems with
* freshness calculations, so we choose the else path...
*/
apr_time_t x = (apr_time_t) ((date - lastmod) * dconf->factor);
if (x < dconf->minex) {
x = dconf->minex;
}
if (x > dconf->maxex) {
x = dconf->maxex;
}
exp = date + x;
}
else {
exp = date + dconf->defex;
}
}
info->expire = exp;
/* We found a stale entry which wasn't really stale. */
if (cache->stale_handle) {
/* RFC 2616 10.3.5 states that entity headers are not supposed
* to be in the 304 response. Therefore, we need to combine the
* response headers with the cached headers *before* we update
* the cached headers.
*
* However, before doing that, we need to first merge in
* err_headers_out (note that store_headers() below already selects
* the cacheable only headers using ap_cache_cacheable_headers_out(),
* here we want to keep the original headers in r->headers_out and
* forward all of them to the client, including non-cacheable ones).
*/
r->headers_out = cache_merge_headers_out(r);
apr_table_clear(r->err_headers_out);
/* Merge in our cached headers. However, keep any updated values. */
/* take output, overlay on top of cached */
cache_accept_headers(cache->handle, r, r->headers_out,
cache->handle->resp_hdrs, 1);
}
/* Write away header information to cache. It is possible that we are
* trying to update headers for an entity which has already been cached.
*
* This may fail, due to an unwritable cache area. E.g. filesystem full,
* permissions problems or a read-only (re)mount. This must be handled
* later.
*/
rv = cache->provider->store_headers(cache->handle, r, info);
/* Did we just update the cached headers on a revalidated response?
*
* If so, we can now decide what to serve to the client. This is done in
* the same way as with a regular response, but conditions are now checked
* against the cached or merged response headers.
*/
if (cache->stale_handle) {
apr_bucket_brigade *bb;
apr_bucket *bkt;
int status;
/* Load in the saved status and clear the status line. */
r->status = info->status;
r->status_line = NULL;
/* We're just saving response headers, so we are done. Commit
* the response at this point, unless there was a previous error.
*/
if (rv == APR_SUCCESS) {
rv = cache->provider->commit_entity(cache->handle, r);
}
bb = apr_brigade_create(r->pool, r->connection->bucket_alloc);
/* Restore the original request headers and see if we need to
* return anything else than the cached response (ie. the original
* request was conditional).
*/
r->headers_in = cache->stale_headers;
status = ap_meets_conditions(r);
if (status != OK) {
r->status = status;
/* Strip the entity headers merged from the cached headers before
* updating the entry (see cache_accept_headers() above).
*/
for (eh = MOD_CACHE_ENTITY_HEADERS; *eh; ++eh) {
apr_table_unset(r->headers_out, *eh);
}
bkt = apr_bucket_flush_create(bb->bucket_alloc);
APR_BRIGADE_INSERT_TAIL(bb, bkt);
}
else {
cache->provider->recall_body(cache->handle, r->pool, bb);
bkt = apr_bucket_eos_create(bb->bucket_alloc);
APR_BRIGADE_INSERT_TAIL(bb, bkt);
}
cache->block_response = 1;
/* Before returning we need to handle the possible case of an
* unwritable cache. Rather than leaving the entity in the cache
* and having it constantly re-validated, now that we have recalled
* the body it is safe to try and remove the url from the cache.
*/
if (rv != APR_SUCCESS) {
ap_log_rerror(APLOG_MARK, APLOG_DEBUG, rv, r, APLOGNO(00772)
"cache: updating headers with store_headers failed. "
"Removing cached url.");
rv = cache->provider->remove_url(cache->stale_handle, r);
if (rv != OK) {
/* Probably a mod_cache_disk cache area has been (re)mounted
* read-only, or that there is a permissions problem.
*/
ap_log_rerror(APLOG_MARK, APLOG_DEBUG, rv, r, APLOGNO(00773)
"cache: attempt to remove url from cache unsuccessful.");
}
/* we've got a cache conditional hit! tell anyone who cares */
cache_run_cache_status(cache->handle, r, r->headers_out,
AP_CACHE_REVALIDATE,
"conditional cache hit: entity refresh failed");
}
else {
/* we've got a cache conditional hit! tell anyone who cares */
cache_run_cache_status(cache->handle, r, r->headers_out,
AP_CACHE_REVALIDATE,
"conditional cache hit: entity refreshed");
}
/* let someone else attempt to cache */
cache_remove_lock(conf, cache, r, NULL);
ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, r, APLOGNO(02971)
"cache: serving %s (revalidated)", r->uri);
return ap_pass_brigade(f->next, bb);
}
if (rv != APR_SUCCESS) {
ap_log_rerror(APLOG_MARK, APLOG_DEBUG, rv, r, APLOGNO(00774)
"cache: store_headers failed");
/* we've got a cache miss! tell anyone who cares */
cache_run_cache_status(cache->handle, r, r->headers_out, AP_CACHE_MISS,
"cache miss: store_headers failed");
ap_remove_output_filter(f);
cache_remove_lock(conf, cache, r, NULL);
return ap_pass_brigade(f->next, in);
}
/* we've got a cache miss! tell anyone who cares */
cache_run_cache_status(cache->handle, r, r->headers_out, AP_CACHE_MISS,
"cache miss: attempting entity save");
return cache_save_store(f, in, conf, cache);
}
/*
* CACHE_REMOVE_URL filter
* -----------------------
*
* This filter gets added in the quick handler every time the CACHE_SAVE filter
* gets inserted. Its purpose is to remove a confirmed stale cache entry from
* the cache.
*
* CACHE_REMOVE_URL has to be a protocol filter to ensure that is run even if
* the response is a canned error message, which removes the content filters
* and thus the CACHE_SAVE filter from the chain.
*
* CACHE_REMOVE_URL expects cache request rec within its context because the
* request this filter runs on can be different from the one whose cache entry
* should be removed, due to internal redirects.
*
* Note that CACHE_SAVE_URL (as a content-set filter, hence run before the
* protocol filters) will remove this filter if it decides to cache the file.
* Therefore, if this filter is left in, it must mean we need to toss any
* existing files.
*/
static apr_status_t cache_remove_url_filter(ap_filter_t *f,
apr_bucket_brigade *in)
{
request_rec *r = f->r;
cache_request_rec *cache;
/* Setup cache_request_rec */
cache = (cache_request_rec *) f->ctx;
if (!cache) {
/* user likely configured CACHE_REMOVE_URL manually; they should really
* use mod_cache configuration to do that. So:
* 1. Remove ourselves
* 2. Do nothing and bail out
*/
ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(00775)
"cache: CACHE_REMOVE_URL enabled unexpectedly");
ap_remove_output_filter(f);
return ap_pass_brigade(f->next, in);
}
/* Now remove this cache entry from the cache */
cache_remove_url(cache, r);
/* remove ourselves */
ap_remove_output_filter(f);
return ap_pass_brigade(f->next, in);
}
/*
* CACHE_INVALIDATE filter
* -----------------------
*
* This filter gets added in the quick handler should a PUT, POST or DELETE
* method be detected. If the response is successful, we must invalidate any
* cached entity as per RFC2616 section 13.10.
*
* CACHE_INVALIDATE has to be a protocol filter to ensure that is run even if
* the response is a canned error message, which removes the content filters
* from the chain.
*
* CACHE_INVALIDATE expects cache request rec within its context because the
* request this filter runs on can be different from the one whose cache entry
* should be removed, due to internal redirects.
*/
static apr_status_t cache_invalidate_filter(ap_filter_t *f,
apr_bucket_brigade *in)
{
request_rec *r = f->r;
cache_request_rec *cache;
/* Setup cache_request_rec */
cache = (cache_request_rec *) f->ctx;
if (!cache) {
/* user likely configured CACHE_INVALIDATE manually; they should really
* use mod_cache configuration to do that. So:
* 1. Remove ourselves
* 2. Do nothing and bail out
*/
ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(02465)
"cache: CACHE_INVALIDATE enabled unexpectedly: %s", r->uri);
}
else {
if (r->status > 299) {
ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(02466)
"cache: response status to '%s' method is %d (>299), not invalidating cached entity: %s", r->method, r->status, r->uri);
}
else {
ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, r, APLOGNO(02467)
"cache: Invalidating all cached entities in response to '%s' request for %s",
r->method, r->uri);
cache_invalidate(cache, r);
/* we've got a cache invalidate! tell everyone who cares */
cache_run_cache_status(cache->handle, r, r->headers_out,
AP_CACHE_INVALIDATE, apr_psprintf(r->pool,
"cache invalidated by %s", r->method));
}
}
/* remove ourselves */
ap_remove_output_filter(f);
return ap_pass_brigade(f->next, in);
}
/*
* CACHE filter
* ------------
*
* This filter can be optionally inserted into the filter chain by the admin as
* a marker representing the precise location within the filter chain where
* caching is to be performed.
*
* When the filter chain is set up in the non-quick version of the URL handler,
* the CACHE filter is replaced by the CACHE_OUT or CACHE_SAVE filter,
* effectively inserting the caching filters at the point indicated by the
* admin. The CACHE filter is then removed.
*
* This allows caching to be performed before the content is passed to the
* INCLUDES filter, or to a filter that might perform transformations unique
* to the specific request and that would otherwise be non-cacheable.
*/
static apr_status_t cache_filter(ap_filter_t *f, apr_bucket_brigade *in)
{
cache_server_conf
*conf =
(cache_server_conf *) ap_get_module_config(f->r->server->module_config,
&cache_module);
/* was the quick handler enabled */
if (conf->quick) {
ap_log_rerror(APLOG_MARK, APLOG_WARNING, 0, f->r, APLOGNO(00776)
"cache: CACHE filter was added in quick handler mode and "
"will be ignored: %s", f->r->unparsed_uri);
}
/* otherwise we may have been bypassed, nothing to see here */
else {
ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, f->r, APLOGNO(00777)
"cache: CACHE filter was added twice, or was added where "
"the cache has been bypassed and will be ignored: %s",
f->r->unparsed_uri);
}
/* we are just a marker, so let's just remove ourselves */
ap_remove_output_filter(f);
return ap_pass_brigade(f->next, in);
}
/**
* If configured, add the status of the caching attempt to the subprocess
* environment, and if configured, to headers in the response.
*
* The status is saved below the broad category of the status (hit, miss,
* revalidate), as well as a single cache-status key. This can be used for
* conditional logging.
*
* The status is optionally saved to an X-Cache header, and the detail of
* why a particular cache entry was cached (or not cached) is optionally
* saved to an X-Cache-Detail header. This extra detail is useful for
* service developers who may need to know whether their Cache-Control headers
* are working correctly.
*/
static int cache_status(cache_handle_t *h, request_rec *r,
apr_table_t *headers, ap_cache_status_e status, const char *reason)
{
cache_server_conf
*conf =
(cache_server_conf *) ap_get_module_config(r->server->module_config,
&cache_module);
cache_dir_conf *dconf = ap_get_module_config(r->per_dir_config, &cache_module);
int x_cache = 0, x_cache_detail = 0;
switch (status) {
case AP_CACHE_HIT: {
apr_table_setn(r->subprocess_env, AP_CACHE_HIT_ENV, reason);
break;
}
case AP_CACHE_REVALIDATE: {
apr_table_setn(r->subprocess_env, AP_CACHE_REVALIDATE_ENV, reason);
break;
}
case AP_CACHE_MISS: {
apr_table_setn(r->subprocess_env, AP_CACHE_MISS_ENV, reason);
break;
}
case AP_CACHE_INVALIDATE: {
apr_table_setn(r->subprocess_env, AP_CACHE_INVALIDATE_ENV, reason);
break;
}
}
apr_table_setn(r->subprocess_env, AP_CACHE_STATUS_ENV, reason);
if (dconf && dconf->x_cache_set) {
x_cache = dconf->x_cache;
}
else {
x_cache = conf->x_cache;
}
if (x_cache) {
apr_table_setn(headers, "X-Cache", apr_psprintf(r->pool, "%s from %s",
status == AP_CACHE_HIT ? "HIT"
: status == AP_CACHE_REVALIDATE ? "REVALIDATE" : status
== AP_CACHE_INVALIDATE ? "INVALIDATE" : "MISS",
r->server->server_hostname));
}
if (dconf && dconf->x_cache_detail_set) {
x_cache_detail = dconf->x_cache_detail;
}
else {
x_cache_detail = conf->x_cache_detail;
}
if (x_cache_detail) {
apr_table_setn(headers, "X-Cache-Detail", apr_psprintf(r->pool,
"\"%s\" from %s", reason, r->server->server_hostname));
}
return OK;
}
/**
* If an error has occurred, but we have a stale cached entry, restore the
* filter stack from the save filter onwards. The canned error message will
* be discarded in the process, and replaced with the cached response.
*/
static void cache_insert_error_filter(request_rec *r)
{
void *dummy;
cache_dir_conf *dconf;
/* ignore everything except for 5xx errors */
if (r->status < HTTP_INTERNAL_SERVER_ERROR) {
return;
}
dconf = ap_get_module_config(r->per_dir_config, &cache_module);
if (!dconf->stale_on_error) {
return;
}
/* RFC2616 13.8 Errors or Incomplete Response Cache Behavior:
* If a cache receives a 5xx response while attempting to revalidate an
* entry, it MAY either forward this response to the requesting client,
* or act as if the server failed to respond. In the latter case, it MAY
* return a previously received response unless the cached entry
* includes the "must-revalidate" cache-control directive (see section
* 14.9).
*
* This covers the case where the error was generated by our server via
* ap_die().
*/
apr_pool_userdata_get(&dummy, CACHE_CTX_KEY, r->pool);
if (dummy) {
cache_request_rec *cache = (cache_request_rec *) dummy;
ap_remove_output_filter(cache->remove_url_filter);
if (cache->stale_handle && cache->save_filter
&& !cache->stale_handle->cache_obj->info.control.must_revalidate
&& !cache->stale_handle->cache_obj->info.control.proxy_revalidate
&& !cache->stale_handle->cache_obj->info.control.s_maxage) {
const char *warn_head;
cache_server_conf
*conf =
(cache_server_conf *) ap_get_module_config(r->server->module_config,
&cache_module);
/* morph the current save filter into the out filter, and serve from
* cache.
*/
cache->handle = cache->stale_handle;
if (r->main) {
cache->save_filter->frec = cache_out_subreq_filter_handle;
}
else {
cache->save_filter->frec = cache_out_filter_handle;
}
r->output_filters = cache->save_filter;
r->err_headers_out = cache->stale_handle->resp_hdrs;
/* add a revalidation warning */
warn_head = apr_table_get(r->err_headers_out, "Warning");
if ((warn_head == NULL) || ((warn_head != NULL)
&& (ap_strstr_c(warn_head, "111") == NULL))) {
apr_table_mergen(r->err_headers_out, "Warning",
"111 Revalidation failed");
}
cache_run_cache_status(
cache->handle,
r,
r->err_headers_out,
AP_CACHE_HIT,
apr_psprintf(
r->pool,
"cache hit: %d status; stale content returned",
r->status));
/* give someone else the chance to cache the file */
cache_remove_lock(conf, cache, r, NULL);
}
}
return;
}
/* -------------------------------------------------------------- */
/* Setup configurable data */
static void *create_dir_config(apr_pool_t *p, char *dummy)
{
cache_dir_conf *dconf = apr_pcalloc(p, sizeof(cache_dir_conf));
dconf->no_last_mod_ignore = 0;
dconf->store_expired = 0;
dconf->store_private = 0;
dconf->store_nostore = 0;
/* maximum time to cache a document */
dconf->maxex = DEFAULT_CACHE_MAXEXPIRE;
dconf->minex = DEFAULT_CACHE_MINEXPIRE;
/* default time to cache a document */
dconf->defex = DEFAULT_CACHE_EXPIRE;
/* factor used to estimate Expires date from LastModified date */
dconf->factor = DEFAULT_CACHE_LMFACTOR;
dconf->x_cache = DEFAULT_X_CACHE;
dconf->x_cache_detail = DEFAULT_X_CACHE_DETAIL;
dconf->stale_on_error = DEFAULT_CACHE_STALE_ON_ERROR;
/* array of providers for this URL space */
dconf->cacheenable = apr_array_make(p, 10, sizeof(struct cache_enable));
return dconf;
}
static void *merge_dir_config(apr_pool_t *p, void *basev, void *addv) {
cache_dir_conf *new = (cache_dir_conf *) apr_pcalloc(p, sizeof(cache_dir_conf));
cache_dir_conf *add = (cache_dir_conf *) addv;
cache_dir_conf *base = (cache_dir_conf *) basev;
new->no_last_mod_ignore = (add->no_last_mod_ignore_set == 0) ? base->no_last_mod_ignore : add->no_last_mod_ignore;
new->no_last_mod_ignore_set = add->no_last_mod_ignore_set || base->no_last_mod_ignore_set;
new->store_expired = (add->store_expired_set == 0) ? base->store_expired : add->store_expired;
new->store_expired_set = add->store_expired_set || base->store_expired_set;
new->store_private = (add->store_private_set == 0) ? base->store_private : add->store_private;
new->store_private_set = add->store_private_set || base->store_private_set;
new->store_nostore = (add->store_nostore_set == 0) ? base->store_nostore : add->store_nostore;
new->store_nostore_set = add->store_nostore_set || base->store_nostore_set;
/* maximum time to cache a document */
new->maxex = (add->maxex_set == 0) ? base->maxex : add->maxex;
new->maxex_set = add->maxex_set || base->maxex_set;
new->minex = (add->minex_set == 0) ? base->minex : add->minex;
new->minex_set = add->minex_set || base->minex_set;
/* default time to cache a document */
new->defex = (add->defex_set == 0) ? base->defex : add->defex;
new->defex_set = add->defex_set || base->defex_set;
/* factor used to estimate Expires date from LastModified date */
new->factor = (add->factor_set == 0) ? base->factor : add->factor;
new->factor_set = add->factor_set || base->factor_set;
new->x_cache = (add->x_cache_set == 0) ? base->x_cache : add->x_cache;
new->x_cache_set = add->x_cache_set || base->x_cache_set;
new->x_cache_detail = (add->x_cache_detail_set == 0) ? base->x_cache_detail
: add->x_cache_detail;
new->x_cache_detail_set = add->x_cache_detail_set
|| base->x_cache_detail_set;
new->stale_on_error = (add->stale_on_error_set == 0) ? base->stale_on_error
: add->stale_on_error;
new->stale_on_error_set = add->stale_on_error_set
|| base->stale_on_error_set;
new->cacheenable = add->enable_set ? apr_array_append(p, base->cacheenable,
add->cacheenable) : base->cacheenable;