>Number: 5686
>Category: mod_proxy
>Synopsis: mod_proxy functionality extensions when acting as a backend
>httpd (i.e. mod_perl) accelerator
>Confidential: no
>Severity: non-critical
>Priority: medium
>Responsible: apache
>State: open
>Class: change-request
>Submitter-Id: apache
>Arrival-Date: Wed Feb 02 09:20:00 PST 2000
>Closed-Date:
>Last-Modified:
>Originator: [EMAIL PROTECTED]
>Release: 1.3.9
>Organization:
apache
>Environment:
FreeBSD 3.4-RC #25: Fri Dec 10 19:16:55 MSK 1999 [EMAIL
PROTECTED]:/usr/src/sys/compile/POLIT i386
>Description:
Fixes was done for apache version 1.3.9. But I think it should work
with 1.3.4 and higher versions too. I've not tested it with versions
other than 1.3.9, and I've not tested it on Win32 platform.
1) Subtle problem with mod_include/mod_rewrite/mod_proxy.
mod_include reports error when receiving response code other than
HTTP_OK. So I've fixed mod_proxy so that it can return
HTTP_NOT_MODIFIED only if request is not subrequest. Also, I've
enabled mod_rewrite ruleflag [P] on subrequests.
Patched files: proxy_cache.c, mod_rewrite.c
2) Large amount of reloads cause very high load on backend because
requests bypass the cache. I've added IgnoreNoCache <filemask>
directive to mod_proxy config. <Filemask> is a mask for frontend
server URIs. When mask is matched, Pragma: no-cache header is
being deleted from incoming file headers, so if cached data
present, it would be returned instead of getting data from
backend server.
Patched files: proxy_cache.c, mod_proxy.c, mod_proxy.h
Added config cmds: IgnoreNoCache <location mask (not regexp!)>
Context: global (not tested) & vhost
3) On site with a very high traffic, there's a real risk of
simultaneous reloading of the same URI by numerous clients.
This is also causes problems on backend, especially with
complicated dynamically-generated pages. I've fixed this by
adding mod_proxy directive NoConcurrentCacheUpdates (On|Off),
and new scoreboard status SERVER_PROXY_READ. When the flag is on
and expired data found, server first checks if this URI is being
downloaded from upstream by any other child. If so, it returns
expired data to client while 'downloading' child doing its job of
updating the cache.
Patched files: proxy_cache.c, mod_proxy.c, mod_proxy.h,
mod_status.h, scoreboard.h
Added config cmds: NoConcurrentCacheUpdates (On|Off)
Context: global (not tested) & vhost
4) I've added X-Real-IP header to present real IP to the backend
server. I think that X-Forwarded-For is for REAL proxies, so I
don't want to mess with it.
Patched files: proxy_http.c
5) I've replaced ExplainX macros in proxy_cache.c for ap_log_rerror
API call. Seems that those macros don't work, dunno why...
Patched files: proxy_cache.c
>How-To-Repeat:
>Fix:
patches are available
http://web.masterskaya.ru/~ilya/apache/xfire_patches1.3.9.tar.gz
>Release-Note:
>Audit-Trail:
>Unformatted:
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