Serving multiple sites from varnish

Question

I have several sites that I want to cache using the same instance of varnish.

I did setup the backend using something like:

if (req.http.host == "time.ikub.al") {
    # Process through time backend
    set req.backend_hint = timeserver;
}

if (req.http.host == "m.time.ikub.al") {
    # Process through time mobile backend
    set req.backend_hint = timemobileserver;
}

and hash method looks like:

sub vcl_hash {
    # Called after vcl_recv to create a hash value for the request. This is used as a key
    # to look up the object in Varnish.
    hash_data(req.url);
    if (req.http.host) {
       hash_data(req.http.host);
    } else {
       hash_data(server.ip);
    }
    # hash cookies for requests that have them
    if (req.http.Cookie) {
        hash_data(req.http.Cookie);
    }
}

However, I noticed that pages from mobile version where served when on desktop and vice-versa. This happened on pages with the same name, for example "Default.aspx".

As I understand the code above the hash should include the host part and this should not happen. Am I missing something, or is there some recommendation on how to handle multiple sites?

Thanx, Albert

Answer 1

I was under impression that "redirects" were not cached...however it seems that redirects are cached and what's happening is that a redirect response from the desktop version is cached and the next client is served the cached page so it redirect him to mobile version...I moved the redirect logic to client side and things seems to work