CODEWITHSUNDEEP
varnishvarnish-vclfastlyfastly-vcl
Yuri Astrakhan
Yuri Astrakhan

Reputation: 9965

Accessing the body of the backend response in Varnish VCL

My Varnish VCL code needs to make a simple GET request into a backend system and decide if the requested resource is accessible or not. Unfortunately, the backend system always returns 200, and I must examine the actual body of the response to decide.

Is there a way to access the response body (which is under 1KB) in VCL and do a substring search on it?

I am trying to avoid implementing a proxy service just for this feature.

P.S. For now I have to stick with Varnish 2.1 (Fastly)

Upvotes: 2

Views: 1112

Answers (3)

PajE
PajE

Reputation: 759

With varnish You probably should use external vmods for that

Opensource version: body-access in https://github.com/varnish/varnish-modules

Varnish Software/Entrprise : https://docs.varnish-software.com/varnish-enterprise/vmods/xbody/

Upvotes: 0

Nils Goroll
Nils Goroll

Reputation: 168

There is a way for some time now: You can use the .match_body() method of regex objects provided by vmod_re.

Upvotes: 0

Guillaume Quintard
Guillaume Quintard

Reputation: 619

Quick answer: no. Fastly's Varnish has diverged a lot from mainline, so you are basically stuck with what they provide and response body analysis isn't part of it.

Varnish 6.0 and 6.1 internals make that easier to build, but at the moment the vmod (xbody) you need is only available as a commercial product.

Upvotes: 4

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