using rsprep to change response status affects other ACL's

I just want to make sure that this is the expected behavior:

    [root#tt3 ~]# haproxy -v
    HA-Proxy version 1.4.8 2010/06/16

And the snippet of a config showing the behavior. If the response from the server is a 404, we want to change the status to 555. If the status is 555 add a Location header:

    frontend main *:80

        default_backend site1

    backend site1

        acl not_found               status 404
        acl bizzare_status          status 555

        rspadd  X-Wibble:\ bizzare                          if bizzare_status
        rspadd  X-Wibble:\ not_found                        if not_found

        rsprep ^HTTP/1.1\ 404\ (.*)$ HTTP/1.1\ 555\ Bizzare if not_found


        server      site1 127.0.0.1:81 check

Curl session against a haproxy with the above config:

    % curl --verbose --silent http://tt3/foo.html > /dev/null

• About to connect() to tt3 port 80 (#0)
• Trying 10.10.12.17... connected
• Connected to tt3 (10.10.12.17) port 80 (#0)
  > GET /foo.html HTTP/1.1
  > User-Agent: curl/7.20.0 (i386-apple-darwin10.3.0) libcurl/7.20.0 OpenSSL/0.9.8n zlib/1.2.5 libidn/1.18
  > Host: tt3
  > Accept: */*
  >
  < HTTP/1.1 555 Bizzare < Server: nginx/0.6.39 < Date: Fri, 09 Jul 2010 21:36:54 GMT < Content-Type: text/html < Content-Length: 3653 < Connection: close < X-Wibble: bizzare < { [data not shown]
• Closing connection #0

What this appears to show, is that both of the status based ACL's are satisfied at different times. That is, it appears that the following happens:

• request sent to site1 and site1 response with a 404
• at this point acl 'not_found' is true, which means that acl 'bizzare_status' must be false
• rsprep changes the 404 response to a 555
• rspadd adds 'X-Wibble: bizzare' header, which means that acl 'bizzare_status' was true

I'm okay with this, and can work with it. I just want to make sure that this is the expected behavior.

enjoy,

-jeremy

--
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 Jeremy Hinegardner                              jeremy#hinegardner.org