Hi,
I use the AddOutputFilterByType directive to insert a few output
filters into the filter chain for certain MIME types. After observing
unexpected behaviour of the server I found out that these filters are
added twice (via ap_set_content_type function):
- first inside the find_ct type_checker hook of the MIME module, based
on the content of the TypesConfig file;
- then in the ap_proxy_http_process_response function, based on the
Content-Type header returned by the back-end server.
Clearly the MIME hook should not try and guess about the content type
of the proxied requests. Since it does it by parsing r->filename,
perhaps it should also check if the latter starts with "proxy:" or if
r->proxyreq is set?
There is a comment in mod_proxy.c mentioning type_checker and
PROXY_MAGIC_TYPE but no corresponding code. I suspect the code did
exist in past revisions. Apparently the idea was to use a special
magic type for proxied requests and have this hook called before the
MIME module one. Where has it gone?
For now as a workaround in proxied VirtualHosts I use "TypesConfig /
dev/null". This is because Apache uses a hardcoded location of the
file if the directive is missing completely, so I need to override it
explicitly. This is far from perfect, especially if I need to process
some of the paths of these VirtualHosts locally by the proxy.
Since there can be multiple different fixes of this bug and I'm not
sure which is better, I haven't provided the patch.
Any ideas?
Konstantin Chuguev
Software Developer
Clickstream Technologies PLC, 58 Davies Street, London, W1K 5JF,
Registered in England No. 3774129
