Check body length in VCL

T. Pascal t_pascal at
Wed Aug 11 20:11:32 CEST 2010

It is sometimes useful to use the following rule to make decisions in VCL,
based on Content-Length:

vcl_fetch() {
# Cache objects larger than 3000 bytes
if ((beresp.status == 200) && (beresp.http.Content-Length ~
"^([3-9]|\d\d)\d\d\d")) {
  set beresp.ttl = 10d;
} else {
  set beresp.ttl = 10m;
} }

The use case is an XML feed that we heuristically know is "well formed" if
it's more then 3K; if the response is shorter, it often means the result set
was empty for whatever reason (even if it's an HTTP-200 response), so we
cache the short requests for a small time until the full result is ready and
then cache it for a long time.

This is a horrible hack that works fine, until we get some chunked responses
and the above regexp fails.

So I would prefer:

if ((beresp.status == 200) && (length(body) > 3000)) {
  # Cache a long time

Does this exist without in-line C, is it a valuable feature, etc. so forth?

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <>

More information about the varnish-dev mailing list