Hypermail

From: Benedikt Fraunhofer <fraunhof#traced.net>
Date: Wed, 28 Apr 2010 12:11:51 +0200

Hi Andrew,

2010/4/28 Andrew Commons <andrew.commons#bigpond.com>:

> url_beg <string>
> Returns true when the URL begins with one of the strings. This can be used to
> check whether a URL begins with a slash or with a protocol scheme.
>
> So I'm assuming that "protocol scheme" means http:// or ftp:// or whatever....

I would assume that, too..
but :) reading the other matching options it looks like those only affect the "anchoring" of the matching. Like

> url_ip <ip_address>
> Applies to the IP address specified in the absolute URI in an HTTP request.
> It can be used to prevent access to certain resources such as local network.
> It is useful with option "http_proxy".

yep. but watch this "http_proxy"

> url_port <integer>
> "http_proxy". Note that if the port is not specified in the request, port 80
> is assumed.

same here.. This enables plain proxy mode where requests are issued (from the client) like

GET http://www.example.com/importantFile.txt HTTP/1.0 .

> This seems to be reinforced (I think!) by:
>
> url_dom <string>
> Returns true when one of the strings is found isolated or delimited with dots
> in the URL. This is used to perform domain name matching without the risk of
> wrong match due to colliding prefixes. See also "url_sub".

I personally don't think so.. I guess this is just another version of "anchoring", here
"\.$STRING\."
> If I'm suffering from a bit of 'brain fade' here just set me on the right road :-) If the url_ criteria have different interpretations in terms of what the 'url' is then let's find out what these are!

I currently can't give it a try as i finally managed to lock myself out, but

http://haproxy.1wt.eu/download/1.4/doc/configuration.txt

has an example that looks exactly as what you need:

To select a different backend for requests to static contents on the "www" site and to every request on the "img", "video", "download" and "ftp" hosts :

   acl url_static  path_beg         /static /images /img /css
   acl url_static  path_end         .gif .png .jpg .css .js

acl host_www hdr_beg(host) -i www
acl host_static hdr_beg(host) -i img. video. download. ftp.

# now use backend "static" for all static-only hosts, and for static urls # of host "www". Use backend "www" for the rest. use_backend static if host_static or host_www url_static use_backend www if host_www

and as "begin" really means anchoring it with "^" in a regex this would mean that there's no host in url as this would redefine the meaning of "begin" which should not be done :)

So you should be fine with

       acl xxx_host     hdr(Host)      -i xxx.example.com
       acl xxx_url      url_beg /
       #there's already a predefined acl doing this.
       use_backend xxx         if xxx_host xxx_url

if i recall your example correctly.. But you should really put something behind the url_beg to be of any use :)

Just my 2 cent

Beni. Received on 2010/04/28 12:11

Re: Matching URLs at layer 7