>Number: 5237
>Category: mod_proxy
>Synopsis: Like PR #659, logging of response headers using mod_log_config
>from requests handled by mod_proxy isn't possible.
>Confidential: no
>Severity: non-critical
>Priority: medium
>Responsible: apache
>State: open
>Class: sw-bug
>Submitter-Id: apache
>Arrival-Date: Wed Nov 3 04:10:01 PST 1999
>Last-Modified:
>Originator: [EMAIL PROTECTED]
>Organization:
apache
>Release: 1.3.9
>Environment:
Solaris 2.7, gcc
>Description:
mod_proxy builds up its own list of response headers in resp_hdrs, which it
then sends using an ap_table_do and ap_proxy_send_hdr_line. I've previously
reported that this means you can't use mod_headers/mod_usertrack to add response
headers to a proxied request. I've now noticed this means you don't get correct
behaviour when using %{}o format arguments in mod_log_config with proxied
requests, because of course these log from r->headers_out, which doesn't contain
any of the response headers which mod_proxy gets from the downstream server.
There is a hack in mod_log_config to output r->content_type if you ask for
%{Content-Type}o instead of the value from r->headers_out. This means that
for proxied requests you get output the value from r->content_type logged which
is set based on what mod_mime works out as the content-type based on the url
extension, and not what is returned as a header by the downstream server
(hence the behaviour in PR #659 I believe, tho' it was claimed to be fixed in
that PR).
>How-To-Repeat:
Log any output header, especially Content-Type, in mod_log_config for proxied
requests, and note that the values are not taken from headers returned by
the downstream server, but from any values previous apache modules may have
set.
>Fix:
I think content-type is probably the main output header that people would be
interested in logging for requests, so I would suggest that in proxy_http.c you
set r->content_type based on any Content-Type header returned by the downstream
server. Another possibility is to add (in addition to the prior step) all the
response headers to r->headers_out (with headers in resp_hdrs overwriting any
matching headers in r->headers_out). If this was done, it'd be nice to then
output r->headers_out instead of resp_hdrs to the client, to allow modification
of response headers for proxied requests by any prior modules.
overrides any headers in r->headers_out.
>Audit-Trail:
>Unformatted:
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