html redirects getting blocked while using varnish

Question

I am using varnish 3.0 on ubuntu 11 - the redirect is being handled by expressjs(v2.5.8 - running node.js 0.6) - the redirect is called by express (works without varnish in between) but when varnish is used in between, the redirect to a new page gets blocked (displays 'Error 302 found').

In the vcl config file for varnish, I have attempted to pass(return) based on URL and Referer (in the sub vcl_recv section) but I appear to have misconfigured (or need to add more config steps). Any thoughts/suggestions for changes in the vcl file would be quite welcome which would allow varnish to let expressjs redirect to new page.

Thanks in advance.

I am also trying to pass(return) in sub_vcl_fetch section. Any suggestions would be welcome. — ali haider
resolved by modifying the sub_vcl_fetch section - I will post here soon - hope it helps. — ali haider

ali haider ali haider · Accepted Answer · 2012-03-29T14:40:48

Changing the sub_vcl_fetch fixed it.

I have copied part of the sub_vcl_fetch section from my vcl file below:

sub vcl_fetch {

# Do not cache the object if the backend application does not want us to.
if (beresp.http.Cache-Control ~ "(no-cache|no-store|private|must-revalidate)") {
return(pass);
}

# Do not cache the object if the status is not in the 200s
if (beresp.status >= 300) {
# Remove the Set-Cookie header
#remove beresp.http.Set-Cookie;
return(pass);
}

#
# Everything below here should be cached
#
# Remove the Set-Cookie header
####remove beresp.http.Set-Cookie;

# Set the grace time
set beresp.grace = 1s;

# Static assets aren't served out of Varnish just yet, but when they are, this will
# make sure the browser caches them for a long time.
if (req.url ~ "\.(css|js|jpg|jpeg|gif|ico|png)\??\d*$") {
/* Remove Expires from backend, it's not long enough */
unset beresp.http.expires;

/* Set the clients TTL on this object */
set beresp.http.cache-control = "public, max-age=31536000";

/* marker for vcl_deliver to reset Age: */
set beresp.http.magicmarker = "1";} else {
set beresp.http.Cache-Control = "private, max-age=0, must-revalidate";
set beresp.http.Pragma = "no-cache";}

## If the request to the backend returns a code other than 200, restart the loop
## If the number of restarts reaches the value of the parameter max_restarts,
## the request will be error'ed.  max_restarts defaults to 4.  This prevents
## an eternal loop in the event that, e.g., the object does not exist at all.
if (beresp.status != 200 && beresp.status != 403 && beresp.status != 404) {
restart;
}


if (beresp.status == 302) {
return(deliver);}
# return(deliver); the object
return(deliver);
}

Hope this helps!

html redirects getting blocked while using varnish

1 Answers