How do I disable 'Transfer-Encoding: chunked' encoding in Varnish?

Question

Using Varnish 4, I have a set of backends that're responding with a valid `Content-Length` header and no `Transfer-Encoding` header. On the first hit from a client, rather than responding to the client with those headers, Varnish is dropping the `Content-Length` header and adding `Transfer-Encoding: chunked` to the response. (Interestingly, the payload doesn't appear to have any chunks in it - it's one contiguous payload). This causes serious problems for clients like Flash video players that are trying to do segment-size, bandwidth, etc analysis based on the `Content-Length` header. Their analysis fails, and they can't do things like multi-bitrate streaming, etc. I've tried a number of semi-obvious things like: - `beresp.do_stream = true` - `beresp.do_gzip = false` - `unset req.http.Accept-Encoding` Sample backend response: ``` HTTP/1.1 200 OK Cache-Control: public, max-age=600 Content-Type: video/mp4 Date: Tue, 13 May 2014 19:44:35 GMT Server: Apache Content-Length: 796618 Connectio…

Accepted Answer

For the time being, `do_stream = false` will do what you want.

Avoiding chunked encoding for the case where the backend sends unchunked is a possible future improvement to Varnish.

Example:

```
sub vcl_backend_response {
        if(beresp.http.Content-Type ~ "video") {
                set beresp.do_stream = false;
                set beresp.do_gzip = false;
                //set resp.http.Content-Length = beresp.http.Content-Length;
        }
        if(beresp.http.Edge-Control == "no-store") {
                set beresp.uncacheable = true;
                set beresp.ttl = 60s;
                set beresp.http.Smug-Cacheable = "No";
                return(deliver);
        }
}
```

How do I disable 'Transfer-Encoding: chunked' encoding in Varnish?

Solution

Problem