Use gzip content encoding only if supported by client

[tkSimon]

At the moment deluge responds to requests for certain resource with gzip content encoding regardless of the requests accept-encoding header. It should only use gzip encoding if supported by the client.

Personally, I wanted deluge to respond with uncompressed assets because i have an nginx reverse proxy in front of deluge that's doing brotli (and gzip compression,) and caching those. The issue being that nginx only compresses when the origin (deluge) sends them uncompressed. This is usually achieved by configuring nginx to not forward the accept-encoding header.

To reproduce, run: curl 127.0.0.1:8112/js/ext-extensions.js -o /dev/null -v

The response will have a "Content-Encoding: gzip" header, and it's payload will be gzipped even though the request doesn't contain an "Accpet-Encoding: gzip" header.

I created a PR to fix this: ​https://github.com/deluge-torrent/deluge/pull/232

[Calum]

Based on your use-case I agree that this would be good to fix.

Using the Twisted resource wrapper is a better way to do this and I have created a PR: ​https://github.com/deluge-torrent/deluge/pull/233

We should also only compress text and not images and that can be included in the changes.

[Calum]

Fixed in develop: [db021b9f415]