nginx_proxy: Fix issue #3132

[mancontr]

Issue #3132, affecting nginx_proxy, has been causing other addons to break for a long time. For example, part of the esphome addon is not usable through the nginx_proxy because of this bug. All the details are in the issue.

The fix is very simple: replace $host with $http_host, so the port gets included and the socket connection is not detected as cross-origin.

I've had this fix applied on a custom config since the issue was opened, without any problems, but I think it would be nice to fix it here for everyone.

[home-assistant]

Hi @mancontr

It seems you haven't yet signed a CLA. Please do so here.

Once you do that we will be able to review and accept this pull request.

Thanks!

[home-assistant]

Please take a look at the requested changes, and use the Ready for review button when you are done, thanks 👍

Learn more about our pull request process.

Stale

[agners]

Nice catch!

Without understanding too much here, from this StackOverflow thread it seems that another difference is that $http_host is from the client request. Can it be trusted? 🤔

[agners]

Please also bump the version in config.yaml and add your change to CHANGELOG.md.

[mancontr]

I updated the changelog and bumped the version, following the example from the v3.4.0 release, which was somewhat similar.

Regarding the safety considerations of the change: both $host and $http_host use values provided by the client, so there isn't much of a change (other than adding the port). Of course neither value can be trusted, but we're merely forwarding them to the addon, which can receive them directly from a client when not using the proxy, so AFAIK we shouldn't be creating any new problems by doing this.