[squid-users] loop 302
HackXBack
hack.back at hotmail.com
Sat Apr 25 11:10:18 UTC 2015
--- src/Server.cc
+++ src/Server.cc
@@ -31,6 +31,7 @@
*/
#include "squid.h"
+#include "acl/FilledChecklist.h"
#include "acl/Gadgets.h"
#include "base/TextException.h"
#include "comm/Connection.h"
@@ -174,6 +175,8 @@
// give entry the reply because haveParsedReplyHeaders() expects it
there
entry->replaceHttpReply(theFinalReply, false); // but do not write yet
haveParsedReplyHeaders(); // update the entry/reply (e.g., set
timestamps)
+ if (EBIT_TEST(entry->flags, ENTRY_CACHABLE) && blockCaching())
+ entry->release();
entry->startWriting(); // write the updated entry to store
return theFinalReply;
@@ -533,6 +536,24 @@
currentOffset = partial ? theFinalReply->content_range->spec.offset :
0;
}
+/// whether to prevent caching of an otherwise cachable response
+bool
+ServerStateData::blockCaching()
+{
+ if (const Acl::Tree *acl = Config.accessList.storeMiss) {
+ // This relatively expensive check is not in
StoreEntry::checkCachable:
+ // That method lacks HttpRequest and may be called too many times.
+ ACLFilledChecklist ch(acl, originalRequest(), NULL);
+ ch.reply = const_cast<HttpReply*>(entry->getReply()); //
ACLFilledChecklist API bug
+ HTTPMSGLOCK(ch.reply);
+ if (ch.fastCheck() != ACCESS_ALLOWED) { // when in doubt, block
+ debugs(20, 3, "store_miss prohibits caching");
+ return true;
+ }
+ }
+ return false;
+}
+
HttpRequest *
ServerStateData::originalRequest()
{
--- src/Server.h
+++ src/Server.h
@@ -131,6 +131,8 @@
/// Entry-dependent callbacks use this check to quit if the entry went
bad
bool abortOnBadEntry(const char *abortReason);
+ bool blockCaching();
+
#if USE_ADAPTATION
void startAdaptation(const Adaptation::ServiceGroupPointer &group,
HttpRequest *cause);
void adaptVirginReplyBody(const char *buf, ssize_t len);
--- src/SquidConfig.h
+++ src/SquidConfig.h
@@ -375,6 +375,8 @@
acl_access *AlwaysDirect;
acl_access *ASlists;
acl_access *noCache;
+ acl_access *sendHit;
+ acl_access *storeMiss;
acl_access *stats_collection;
#if SQUID_SNMP
--- src/cf.data.pre
+++ src/cf.data.pre
@@ -4843,18 +4843,97 @@
NAME: cache no_cache
TYPE: acl_access
DEFAULT: none
-DEFAULT_DOC: Allow caching, unless rules exist in squid.conf.
+DEFAULT_DOC: By default, this directive is unused and has no effect.
LOC: Config.accessList.noCache
DOC_START
- A list of ACL elements which, if matched and denied, cause the request to
- not be satisfied from the cache and the reply to not be cached.
- In other words, use this to force certain objects to never be cached.
-
- You must use the words 'allow' or 'deny' to indicate whether items
- matching the ACL should be allowed or denied into the cache.
+ Requests denied by this directive will not be served from the cache
+ and their responses will not be stored in the cache. This directive
+ has no effect on other transactions and on already cached responses.
This clause supports both fast and slow acl types.
See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
+
+ This and the two other similar caching directives listed below are
+ checked at different transaction processing stages, have different
+ access to response information, affect different cache operations,
+ and differ in slow ACLs support:
+
+ * cache: Checked before Squid makes a hit/miss determination.
+ No access to reply information!
+ Denies both serving a hit and storing a miss.
+ Supports both fast and slow ACLs.
+ * send_hit: Checked after a hit was detected.
+ Has access to reply (hit) information.
+ Denies serving a hit only.
+ Supports fast ACLs only.
+ * store_miss: Checked before storing a cachable miss.
+ Has access to reply (miss) information.
+ Denies storing a miss only.
+ Supports fast ACLs only.
+
+ If you are not sure which of the three directives to use, apply the
+ following decision logic:
+
+ * If your ACL(s) are of slow type _and_ need response info, redesign.
+ Squid does not support that particular combination at this time.
+ Otherwise:
+ * If your directive ACL(s) are of slow type, use "cache"; and/or
+ * if your directive ACL(s) need no response info, use "cache".
+ Otherwise:
+ * If you do not want the response cached, use store_miss; and/or
+ * if you do not want a hit on a cached response, use send_hit.
+DOC_END
+
+NAME: send_hit
+TYPE: acl_access
+DEFAULT: none
+DEFAULT_DOC: By default, this directive is unused and has no effect.
+LOC: Config.accessList.sendHit
+DOC_START
+ Responses denied by this directive will not be served from the cache
+ (but may still be cached, see store_miss). This directive has no
+ effect on the responses it allows and on the cached objects.
+
+ Please see the "cache" directive for a summary of differences among
+ store_miss, send_hit, and cache directives.
+
+ Unlike the "cache" directive, send_hit only supports fast acl
+ types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
+
+ For example:
+
+ # apply custom Store ID mapping to some URLs
+ acl MapMe dstdomain .c.example.com
+ store_id_program ...
+ store_id_access allow MapMe
+
+ # but prevent caching of special responses
+ # such as 302 redirects that cause StoreID loops
+ acl Ordinary http_status 200-299
+ store_miss deny MapMe !Ordinary
+
+ # and do not serve any previously stored special responses
+ # from the cache (in case they were already cached before
+ # the above store_miss rule was in effect).
+ send_hit deny MapMe !Ordinary
+DOC_END
+
+NAME: store_miss
+TYPE: acl_access
+DEFAULT: none
+DEFAULT_DOC: By default, this directive is unused and has no effect.
+LOC: Config.accessList.storeMiss
+DOC_START
+ Responses denied by this directive will not be cached (but may still
+ be served from the cache, see send_hit). This directive has no
+ effect on the responses it allows and on the already cached responses.
+
+ Please see the "cache" directive for a summary of differences among
+ store_miss, send_hit, and cache directives. See the
+ send_hit directive for a usage example.
+
+ Unlike the "cache" directive, store_miss only supports fast acl
+ types. See http://wiki.squid-cache.org/SquidFaq/SquidAcl for details.
DOC_END
NAME: max_stale
--- src/client_side_reply.cc
+++ src/client_side_reply.cc
@@ -545,6 +545,11 @@
) {
http->logType = LOG_TCP_NEGATIVE_HIT;
sendMoreData(result);
+ } else if (blockedHit()) {
+ debugs(88, 5, "send_hit forces a MISS");
+ http->logType = LOG_TCP_MISS;
+ processMiss();
+ return;
} else if (!http->flags.internal && refreshCheckHTTP(e, r)) {
debugs(88, 5, "clientCacheHit: in refreshCheck() block");
/*
@@ -773,6 +778,30 @@
}
}
+/// whether squid.conf send_hit prevents us from serving this hit
+bool
+clientReplyContext::blockedHit() const
+{
+ if (!Config.accessList.sendHit)
+ return false; // hits are not blocked by default
+
+ if (http->flags.internal)
+ return false; // internal content "hits" cannot be blocked
+
+ if (const HttpReply *rep = http->storeEntry()->getReply()) {
+ std::auto_ptr<ACLFilledChecklist>
chl(clientAclChecklistCreate(Config.accessList.sendHit, http));
+ chl->reply = const_cast<HttpReply*>(rep); // ACLChecklist API bug
+ HTTPMSGLOCK(chl->reply);
+ return chl->fastCheck() != ACCESS_ALLOWED; // when in doubt, block
+ }
+
+ // This does not happen, I hope, because we are called from CacheHit,
which
+ // is called via a storeClientCopy() callback, and store should
initialize
+ // the reply before calling that callback.
+ debugs(88, 3, "Missing reply!");
+ return false;
+}
+
void
clientReplyContext::purgeRequestFindObjectToPurge()
{
--- src/client_side_reply.h
+++ src/client_side_reply.h
@@ -140,6 +140,7 @@
void triggerInitialStoreRead();
void sendClientOldEntry();
void purgeAllCached();
+ bool blockedHit() const;
void sendBodyTooLargeError();
void sendPreconditionFailedError();
--
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