/* 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.
*/
#include "mod_cache.h"
#include "cache_storage.h"
#include "cache_util.h"
APLOG_USE_MODULE(cache);
extern APR_OPTIONAL_FN_TYPE(ap_cache_generate_key) *cache_generate_key;
extern module AP_MODULE_DECLARE_DATA cache_module;
/* -------------------------------------------------------------- */
/*
* delete all URL entities from the cache
*
*/
int cache_remove_url(cache_request_rec *cache, request_rec *r)
{
cache_provider_list *list;
cache_handle_t *h;
list = cache->providers;
/* Remove the stale cache entry if present. If not, we're
* being called from outside of a request; remove the
* non-stale handle.
*/
h = cache->stale_handle ? cache->stale_handle : cache->handle;
if (!h) {
return OK;
}
ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(00691)
"cache: Removing url %s from the cache", h->cache_obj->key);
/* for each specified cache type, delete the URL */
while (list) {
list->provider->remove_url(h, r);
list = list->next;
}
return OK;
}
/*
* create a new URL entity in the cache
*
* It is possible to store more than once entity per URL. This
* function will always create a new entity, regardless of whether
* other entities already exist for the same URL.
*
* The size of the entity is provided so that a cache module can
* decide whether or not it wants to cache this particular entity.
* If the size is unknown, a size of -1 should be set.
*/
int cache_create_entity(cache_request_rec *cache, request_rec *r,
apr_off_t size, apr_bucket_brigade *in)
{
cache_provider_list *list;
cache_handle_t *h = apr_pcalloc(r->pool, sizeof(cache_handle_t));
apr_status_t rv;
if (!cache) {
/* This should never happen */
ap_log_rerror(APLOG_MARK, APLOG_ERR, APR_EGENERAL, r, APLOGNO(00692)
"cache: No cache request information available for key"
" generation");
return APR_EGENERAL;
}
if (!cache->key) {
rv = cache_generate_key(r, r->pool, &cache->key);
if (rv != APR_SUCCESS) {
return rv;
}
}
list = cache->providers;
/* for each specified cache type, delete the URL */
while (list) {
switch (rv = list->provider->create_entity(h, r, cache->key, size, in)) {
case OK: {
cache->handle = h;
cache->provider = list->provider;
cache->provider_name = list->provider_name;
return OK;
}
case DECLINED: {
list = list->next;
continue;
}
default: {
return rv;
}
}
}
return DECLINED;
}
static int filter_header_do(void *v, const char *key, const char *val)
{
if ((*key == 'W' || *key == 'w') && !ap_cstr_casecmp(key, "Warning")
&& *val == '1') {
/* any stored Warning headers with warn-code 1xx (see section
* 14.46) MUST be deleted from the cache entry and the forwarded
* response.
*/
}
else {
apr_table_addn(v, key, val);
}
return 1;
}
static int remove_header_do(void *v, const char *key, const char *val)
{
if ((*key == 'W' || *key == 'w') && !ap_cstr_casecmp(key, "Warning")) {
/* any stored Warning headers with warn-code 2xx MUST be retained
* in the cache entry and the forwarded response.
*/
}
else {
apr_table_unset(v, key);
}
return 1;
}
static int add_header_do(void *v, const char *key, const char *val)
{
apr_table_addn(v, key, val);
return 1;
}
/**
* Take two sets of headers, sandwich them together, and apply the result to
* r->headers_out.
*
* To complicate this, a header may be duplicated in either table. Should a
* header exist in the top table, all matching headers will be removed from
* the bottom table before the headers are combined. The Warning headers are
* handled specially. Warnings are added rather than being replaced, while
* in the case of revalidation 1xx Warnings are stripped.
*
* The Content-Type and Last-Modified headers are then re-parsed and inserted
* into the request.
*/
void cache_accept_headers(cache_handle_t *h, request_rec *r, apr_table_t *top,
apr_table_t *bottom, int revalidation)
{
const char *v;
if (revalidation) {
r->headers_out = apr_table_make(r->pool, 10);
apr_table_do(filter_header_do, r->headers_out, bottom, NULL);
}
else if (r->headers_out != bottom) {
r->headers_out = apr_table_copy(r->pool, bottom);
}
apr_table_do(remove_header_do, r->headers_out, top, NULL);
apr_table_do(add_header_do, r->headers_out, top, NULL);
v = apr_table_get(r->headers_out, "Content-Type");
if (v) {
ap_set_content_type(r, v);
/*
* Also unset possible Content-Type headers in r->headers_out and
* r->err_headers_out as they may be different to what we have received
* from the cache.
* Actually they are not needed as r->content_type set by
* ap_set_content_type above will be used in the store_headers functions
* of the storage providers as a fallback and the HTTP_HEADER filter
* does overwrite the Content-Type header with r->content_type anyway.
*/
apr_table_unset(r->headers_out, "Content-Type");
apr_table_unset(r->err_headers_out, "Content-Type");
}
/* If the cache gave us a Last-Modified header, we can't just
* pass it on blindly because of restrictions on future values.
*/
v = apr_table_get(r->headers_out, "Last-Modified");
if (v) {
ap_update_mtime(r, apr_date_parse_http(v));
ap_set_last_modified(r);
}
}
/*
* select a specific URL entity in the cache
*
* It is possible to store more than one entity per URL. Content
* negotiation is used to select an entity. Once an entity is
* selected, details of it are stored in the per request
* config to save time when serving the request later.
*
* This function returns OK if successful, DECLINED if no
* cached entity fits the bill.
*/
int cache_select(cache_request_rec *cache, request_rec *r)
{
cache_provider_list *list;
apr_status_t rv;
cache_handle_t *h;
if (!cache) {
/* This should never happen */
ap_log_rerror(APLOG_MARK, APLOG_ERR, APR_EGENERAL, r, APLOGNO(00693)
"cache: No cache request information available for key"
" generation");
return DECLINED;
}
/* if no-cache, we can't serve from the cache, but we may store to the
* cache.
*/
if (!ap_cache_check_no_cache(cache, r)) {
return DECLINED;
}
if (!cache->key) {
rv = cache_generate_key(r, r->pool, &cache->key);
if (rv != APR_SUCCESS) {
return DECLINED;
}
}
/* go through the cache types till we get a match */
h = apr_palloc(r->pool, sizeof(cache_handle_t));
list = cache->providers;
while (list) {
switch ((rv = list->provider->open_entity(h, r, cache->key))) {
case OK: {
char *vary = NULL;
int mismatch = 0;
char *last = NULL;
if (list->provider->recall_headers(h, r) != APR_SUCCESS) {
/* try again with next cache type */
list = list->next;
continue;
}
/*
* Check Content-Negotiation - Vary
*
* At this point we need to make sure that the object we found in
* the cache is the same object that would be delivered to the
* client, when the effects of content negotiation are taken into
* effect.
*
* In plain english, we want to make sure that a language-negotiated
* document in one language is not given to a client asking for a
* language negotiated document in a different language by mistake.
*
* This code makes the assumption that the storage manager will
* cache the req_hdrs if the response contains a Vary
* header.
*
* RFC2616 13.6 and 14.44 describe the Vary mechanism.
*/
vary = cache_strqtok(
apr_pstrdup(r->pool,
cache_table_getm(r->pool, h->resp_hdrs, "Vary")),
CACHE_SEPARATOR, &last);
while (vary) {
const char *h1, *h2;
/*
* is this header in the request and the header in the cached
* request identical? If not, we give up and do a straight get
*/
h1 = cache_table_getm(r->pool, r->headers_in, vary);
h2 = cache_table_getm(r->pool, h->req_hdrs, vary);
if (h1 == h2) {
/* both headers NULL, so a match - do nothing */
}
else if (h1 && h2 && !strcmp(h1, h2)) {
/* both headers exist and are equal - do nothing */
}
else {
/* headers do not match, so Vary failed */
ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS,
r, APLOGNO(00694) "cache_select(): Vary header mismatch.");
mismatch = 1;
break;
}
vary = cache_strqtok(NULL, CACHE_SEPARATOR, &last);
}
/* no vary match, try next provider */
if (mismatch) {
/* try again with next cache type */
list = list->next;
continue;
}
cache->provider = list->provider;
cache->provider_name = list->provider_name;
/*
* RFC2616 13.3.4 Rules for When to Use Entity Tags and Last-Modified
* Dates: An HTTP/1.1 caching proxy, upon receiving a conditional request
* that includes both a Last-Modified date and one or more entity tags as
* cache validators, MUST NOT return a locally cached response to the
* client unless that cached response is consistent with all of the
* conditional header fields in the request.
*/
if (ap_condition_if_match(r, h->resp_hdrs) == AP_CONDITION_NOMATCH
|| ap_condition_if_unmodified_since(r, h->resp_hdrs)
== AP_CONDITION_NOMATCH
|| ap_condition_if_none_match(r, h->resp_hdrs)
== AP_CONDITION_NOMATCH
|| ap_condition_if_modified_since(r, h->resp_hdrs)
== AP_CONDITION_NOMATCH
|| ap_condition_if_range(r, h->resp_hdrs) == AP_CONDITION_NOMATCH) {
mismatch = 1;
}
/* Is our cached response fresh enough? */
if (mismatch || !cache_check_freshness(h, cache, r)) {
const char *etag, *lastmod;
/* Cache-Control: only-if-cached and revalidation required, try
* the next provider
*/
if (cache->control_in.only_if_cached) {
/* try again with next cache type */
list = list->next;
continue;
}
/* set aside the stale entry for accessing later */
cache->stale_headers = apr_table_copy(r->pool,
r->headers_in);
cache->stale_handle = h;
/* if no existing conditionals, use conditionals of our own */
if (!mismatch) {
ap_log_rerror(
APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, r, APLOGNO(00695) "Cached response for %s isn't fresh. Adding "
"conditional request headers.", r->uri);
/* Remove existing conditionals that might conflict with ours */
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");
etag = apr_table_get(h->resp_hdrs, "ETag");
lastmod = apr_table_get(h->resp_hdrs, "Last-Modified");
if (etag || lastmod) {
/* If we have a cached etag and/or Last-Modified add in
* our own conditionals.
*/
if (etag) {
apr_table_set(r->headers_in, "If-None-Match", etag);
}
if (lastmod) {
apr_table_set(r->headers_in, "If-Modified-Since",
lastmod);
}
/*
* Do not do Range requests with our own conditionals: If
* we get 304 the Range does not matter and otherwise the
* entity changed and we want to have the complete entity
*/
apr_table_unset(r->headers_in, "Range");
}
}
/* ready to revalidate, pretend we were never here */
return DECLINED;
}
/* Okay, this response looks okay. Merge in our stuff and go. */
cache_accept_headers(h, r, h->resp_hdrs, r->headers_out, 0);
cache->handle = h;
return OK;
}
case DECLINED: {
/* try again with next cache type */
list = list->next;
continue;
}
default: {
/* oo-er! an error */
return rv;
}
}
}
/* if Cache-Control: only-if-cached, and not cached, return 504 */
if (cache->control_in.only_if_cached) {
ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, r, APLOGNO(00696)
"cache: 'only-if-cached' requested and no cached entity, "
"returning 504 Gateway Timeout for: %s", r->uri);
return HTTP_GATEWAY_TIME_OUT;
}
return DECLINED;
}
static apr_status_t cache_canonicalise_key(request_rec *r, apr_pool_t* p,
const char *path, const char *query,
apr_uri_t *parsed_uri,
const char **key)
{
cache_server_conf *conf;
char *port_str, *hn, *lcs;
const char *hostname, *scheme;
int i;
const char *kpath;
const char *kquery;
if (*key) {
/*
* We have been here before during the processing of this request.
*/
return APR_SUCCESS;
}
/*
* Get the module configuration. We need this for the CacheIgnoreQueryString
* option below.
*/
conf = (cache_server_conf *) ap_get_module_config(r->server->module_config,
&cache_module);
/*
* Use the canonical name to improve cache hit rate, but only if this is
* not a proxy request or if this is a reverse proxy request.
* We need to handle both cases in the same manner as for the reverse proxy
* case we have the following situation:
*
* If a cached entry is looked up by mod_cache's quick handler r->proxyreq
* is still unset in the reverse proxy case as it only gets set in the
* translate name hook (either by ProxyPass or mod_rewrite) which is run
* after the quick handler hook. This is different to the forward proxy
* case where it gets set before the quick handler is run (in the
* post_read_request hook).
* If a cache entry is created by the CACHE_SAVE filter we always have
* r->proxyreq set correctly.
* So we must ensure that in the reverse proxy case we use the same code
* path and using the canonical name seems to be the right thing to do
* in the reverse proxy case.
*/
if (!r->proxyreq || (r->proxyreq == PROXYREQ_REVERSE)) {
if (conf->base_uri && conf->base_uri->hostname) {
hostname = conf->base_uri->hostname;
}
else {
/* Use _default_ as the hostname if none present, as in mod_vhost */
hostname = ap_get_server_name(r);
if (!hostname) {
hostname = "_default_";
}
}
}
else if (parsed_uri->hostname) {
/* Copy the parsed uri hostname */
hn = apr_pstrdup(p, parsed_uri->hostname);
ap_str_tolower(hn);
/* const work-around */
hostname = hn;
}
else {
/* We are a proxied request, with no hostname. Unlikely
* to get very far - but just in case */
hostname = "_default_";
}
/*
* Copy the scheme, ensuring that it is lower case. If the parsed uri
* contains no string or if this is not a proxy request get the http
* scheme for this request. As r->parsed_uri.scheme is not set if this
* is a reverse proxy request, it is ensured that the cases
* "no proxy request" and "reverse proxy request" are handled in the same
* manner (see above why this is needed).
*/
if (r->proxyreq && parsed_uri->scheme) {
/* Copy the scheme and lower-case it */
lcs = apr_pstrdup(p, parsed_uri->scheme);
ap_str_tolower(lcs);
/* const work-around */
scheme = lcs;
}
else {
if (conf->base_uri && conf->base_uri->scheme) {
scheme = conf->base_uri->scheme;
}
else {
scheme = ap_http_scheme(r);
}
}
/*
* If this is a proxy request, but not a reverse proxy request (see comment
* above why these cases must be handled in the same manner), copy the
* URI's port-string (which may be a service name). If the URI contains
* no port-string, use apr-util's notion of the default port for that
* scheme - if available. Otherwise use the port-number of the current
* server.
*/
if (r->proxyreq && (r->proxyreq != PROXYREQ_REVERSE)) {
if (parsed_uri->port_str) {
port_str = apr_pcalloc(p, strlen(parsed_uri->port_str) + 2);
port_str[0] = ':';
for (i = 0; parsed_uri->port_str[i]; i++) {
port_str[i + 1] = apr_tolower(parsed_uri->port_str[i]);
}
}
else if (apr_uri_port_of_scheme(scheme)) {
port_str = apr_psprintf(p, ":%u", apr_uri_port_of_scheme(scheme));
}
else {
/* No port string given in the AbsoluteUri, and we have no
* idea what the default port for the scheme is. Leave it
* blank and live with the inefficiency of some extra cached
* entities.
*/
port_str = "";
}
}
else {
if (conf->base_uri && conf->base_uri->port_str) {
port_str = conf->base_uri->port_str;
}
else if (conf->base_uri && conf->base_uri->hostname) {
port_str = "";
}
else {
/* Use the server port */
port_str = apr_psprintf(p, ":%u", ap_get_server_port(r));
}
}
/*
* Check if we need to ignore session identifiers in the URL and do so
* if needed.
*/
kpath = path;
kquery = conf->ignorequerystring ? NULL : query;
if (conf->ignore_session_id->nelts) {
int i;
char **identifier;
identifier = (char **) conf->ignore_session_id->elts;
for (i = 0; i < conf->ignore_session_id->nelts; i++, identifier++) {
int len;
const char *param;
len = strlen(*identifier);
/*
* Check that we have a parameter separator in the last segment
* of the path and that the parameter matches our identifier
*/
if ((param = ap_strrchr_c(kpath, ';'))
&& !strncmp(param + 1, *identifier, len)
&& (*(param + len + 1) == '=')
&& !ap_strchr_c(param + len + 2, '/')) {
kpath = apr_pstrmemdup(p, kpath, param - kpath);
continue;
}
/*
* Check if the identifier is in the query string and cut it out.
*/
if (kquery && *kquery) {
/*
* First check if the identifier is at the beginning of the
* query string and followed by a '='
*/
if (!strncmp(kquery, *identifier, len) && kquery[len] == '=') {
param = kquery;
}
else {
char *complete;
/*
* In order to avoid subkey matching (PR 48401) prepend
* identifier with a '&' and append a '='
*/
complete = apr_pstrcat(p, "&", *identifier, "=", NULL);
param = ap_strstr_c(kquery, complete);
/* If we found something we are sitting on the '&' */
if (param) {
param++;
}
}
if (param) {
const char *amp;
char *dup = NULL;
if (kquery != param) {
dup = apr_pstrmemdup(p, kquery, param - kquery);
kquery = dup;
}
else {
kquery = "";
}
if ((amp = ap_strchr_c(param + len + 1, '&'))) {
kquery = apr_pstrcat(p, kquery, amp + 1, NULL);
}
else {
/*
* If query string is not "", then we have the case
* that the identifier parameter we removed was the
* last one in the original query string. Hence we have
* a trailing '&' which needs to be removed.
*/
if (dup) {
dup[strlen(dup) - 1] = '\0';
}
}
}
}
}
}
/* Key format is a URI, optionally without the query-string (NULL
* per above if conf->ignorequerystring)
*/
*key = apr_pstrcat(p, scheme, "://", hostname, port_str,
kpath, "?", kquery, NULL);
/*
* Store the key in the request_config for the cache as r->parsed_uri
* might have changed in the time from our first visit here triggered by the
* quick handler and our possible second visit triggered by the CACHE_SAVE
* filter (e.g. r->parsed_uri got unescaped). In this case we would save the
* resource in the cache under a key where it is never found by the quick
* handler during following requests.
*/
ap_log_rerror(APLOG_MARK, APLOG_DEBUG, APR_SUCCESS, r, APLOGNO(00698)
"cache: Key for entity %s?%s is %s", path, query, *key);
return APR_SUCCESS;
}
apr_status_t cache_generate_key_default(request_rec *r, apr_pool_t* p,
const char **key)
{
/* In early processing (quick-handler, forward proxy), we want the initial
* query-string from r->parsed_uri, since any change before CACHE_SAVE
* shouldn't modify the key. Otherwise we want the actual query-string.
*/
const char *path = r->uri;
const char *query = r->args;
if (cache_use_early_url(r)) {
path = r->parsed_uri.path;
query = r->parsed_uri.query;
}
return cache_canonicalise_key(r, p, path, query, &r->parsed_uri, key);
}
/*
* Invalidate a specific URL entity in all caches
*
* All cached entities for this URL are removed, usually in
* response to a POST/PUT or DELETE.
*
* This function returns OK if at least one entity was found and
* removed, and DECLINED if no cached entities were removed.
*/
int cache_invalidate(cache_request_rec *cache, request_rec *r)
{
cache_provider_list *list;
apr_status_t rv, status = DECLINED;
cache_handle_t *h;
apr_uri_t location_uri;
apr_uri_t content_location_uri;
const char *location, *location_key = NULL;
const char *content_location, *content_location_key = NULL;
if (!cache) {
/* This should never happen */
ap_log_rerror(
APLOG_MARK, APLOG_ERR, APR_EGENERAL, r, APLOGNO(00697) "cache: No cache request information available for key"
" generation");
return DECLINED;
}
if (!cache->key) {
rv = cache_generate_key(r, r->pool, &cache->key);
if (rv != APR_SUCCESS) {
return DECLINED;
}
}
location = apr_table_get(r->headers_out, "Location");
if (location) {
if (apr_uri_parse(r->pool, location, &location_uri)
|| cache_canonicalise_key(r, r->pool,
location_uri.path,
location_uri.query,
&location_uri, &location_key)
|| !(r->parsed_uri.hostname
&& location_uri.hostname
&& !strcmp(r->parsed_uri.hostname,
location_uri.hostname))) {
location_key = NULL;
}
}
content_location = apr_table_get(r->headers_out, "Content-Location");
if (content_location) {
if (apr_uri_parse(r->pool, content_location,
&content_location_uri)
|| cache_canonicalise_key(r, r->pool,
content_location_uri.path,
content_location_uri.query,
&content_location_uri,
&content_location_key)
|| !(r->parsed_uri.hostname
&& content_location_uri.hostname
&& !strcmp(r->parsed_uri.hostname,
content_location_uri.hostname))) {
content_location_key = NULL;
}
}
/* go through the cache types */
h = apr_palloc(r->pool, sizeof(cache_handle_t));
list = cache->providers;
while (list) {
/* invalidate the request uri */
rv = list->provider->open_entity(h, r, cache->key);
if (OK == rv) {
rv = list->provider->invalidate_entity(h, r);
status = OK;
}
ap_log_rerror(
APLOG_MARK, APLOG_DEBUG, rv, r, APLOGNO(02468) "cache: Attempted to invalidate cached entity with key: %s", cache->key);
/* invalidate the Location */
if (location_key) {
rv = list->provider->open_entity(h, r, location_key);
if (OK == rv) {
rv = list->provider->invalidate_entity(h, r);
status = OK;
}
ap_log_rerror(
APLOG_MARK, APLOG_DEBUG, rv, r, APLOGNO(02469) "cache: Attempted to invalidate cached entity with key: %s", location_key);
}
/* invalidate the Content-Location */
if (content_location_key) {
rv = list->provider->open_entity(h, r, content_location_key);
if (OK == rv) {
rv = list->provider->invalidate_entity(h, r);
status = OK;
}
ap_log_rerror(
APLOG_MARK, APLOG_DEBUG, rv, r, APLOGNO(02470) "cache: Attempted to invalidate cached entity with key: %s", content_location_key);
}
list = list->next;
}
return status;
}