## Haproxy - unable to manipulate header on a redirect-request

When configuring the different things for Mastodon, I needed to configure .well-known/webfinger on my main domain, in such a way that CORS would pass through.

Using haproxy, this proved to be somewhat difficult - for some reason the normal http-response add-header-magic I was used to using, didn’t work.

After some ducking’, the culprit was found - which was something new to me. Apparently, http-request/http-response is only processed when the request goes through haproxy, and it’s silently ignored when haproxy simply sends the client somewhere else.

The solution is just as simple; http-after-response - see the sources for more info.

sources:

https://github.com/haproxy/haproxy/issues/4

https://cbonte.github.io/haproxy-dconv/2.2/configuration.html#http-after-response