Krist van Besien wrote:
Hello all, I need a way to modify the body of a response when a server responds with an error code. I have a suspicion that this may be possible with squid, but I'm getting a bit confused by the terse documentation. First a bit of background to better understand the problem. We run a website that serves content for mobile phones. This content resides on several backend servers, most of them live with partners who provide our content. We have an "aggregator" that accepts requests from mobile phones, and then in turn requests the content form one or more backend servers. The content these backends deliver is xml, and this xml gets transformed by our aggregator in to something a mobile phone can display. We access these backends through a squid proxy to have some caching. Our problem is that sometimes the backend sends an error (404, 500 etc..) without a properly formed xml body. This causes a thread on our aggregator to block until a timeout is reached. As a result a problem on a backend can lead to resource depletion on our aggregator. On possible solution would be to modify error responses. We want to tack our own xml response body in to any errror response we get from a backend.
Look at the error_map directive (http://www.squid-cache.org/Versions/v2/2.6/cfgman/error_map.html). While it states it is designed for accelerators, I imagine it should work in a forward proxy.
I've done some reading, and came across ICAP, eCam and clientstreams. From the little documentation that is available i'm not sure how to attack this problem. - I only want to modify http responses when the backend server sends an error code (4xx, 5xx). - I only want a simple modification. Basically swap out whatever body in the response with our own. - We currently use squid 2.6. We could move to 3.0 if needed. Any suggestions as to what the best way to solve our problem would be are welcome. Krist van Besien
Chris
