Re: [PATCH] Fix settings options with ProxyPassMatch

[Jan Kaluža]

On 04/29/2014 03:51 PM, Jim Jagielski wrote:

On Apr 29, 2014, at 8:41 AM, Jan Kaluža <jkal...@redhat.com> wrote:

Because later we have to match the URL of request with some proxy_worker.

If you configure ProxyPassMatch like this:
ProxyPassMatch ^/test/(\d+)/foo.jpg http://x/$1/foo.jpg

Then the proxy_worker name would be "http://x/$1/foo.jpg";.

If you receive request with URL "http://x/something/foo.jpg";, ap_proxy_get_worker() will 
have to find out the worker with name "http://x/$1/foo.jpg";. The question here is how it 
would do that?

The answer used in the patch is "we change the worker name to http://x/*/foo.jpg"; and 
check if the URL ("http://x/something/foo.jpg"; in our case) matches that worker.

If we store the original name with $N, we will have to find out different way 
how to match the worker (probably emulating wildcard pattern matching)

It would be possible to store only the original name (with "$N" variables), store the flag that the 
proxy worker is using regex and change ap_proxy_strcmp_ematch() function to treat "$N" as 
"*", but I don't see any real advantage here.

In Yann's suggested patch we don't store match_name where it
belongs; so we'd need to put it in shm, which means more
memory. Instead, we store as is and add a simple char flag
which sez if the stored name is a regex. Much savings.

Hi,

could you please check the patch I've attached to this email?

It changes following parts of Yann's patch:

1. keep only single name of the worker stored in shared memory.

2. when ProxyPassMatch is used, wshared->is_name_matchable = 1.



I've tested this patch a bit and it seems to work for me.

Regards,
Jan Kaluza

3. if is_name_matchable == 1, ap_proxy_get_worker() uses ap_proxy_strcmp_ematch() which treats "$N" as '*'.

And I have no idea why storing with $1 -> * somehow makes
things easier or implies a "different way how to match the worker".

Finally, let's think about this deeper...

Assume we do have

        ProxyPassMatch ^/test/(\d+)/foo.jpg http://x/$1/foo.jpg
        ProxyPassMatch ^/zippy/(\d+)/bar.jpg http://x/$1/omar/propjoe.gif

is the intent/desire to have 2 workers or 1? A worker is, in
some ways, simply a nickname for the socket related to a host and port.
Maybe, in the interests of efficiency and speed, since regexes
are slow as it is, a condition could be specified (a limitation,
as it were), that when using PPM, only everything up to
the 1st potential substitution is considered a unique worker.

httpd-trunk-proxy-matchv2.patch
Description: application/download