Only turn links to current instance into hash links

[silverwind]

Given the following markdown:

http://localhost:3500/silverwind/symlink-test/commit/a832c723cd116df44cce6271c4a89afa4d8ec670
http://localhost:3500/silverwind/remap-css/commit/19fe6cdf81f7ec50b8cac2d6c28fe7c42c1ffe14
http://github.com/silverwind/symlink-test/commit/a832c723cd116df44cce6271c4a89afa4d8ec670

Previously, all links would turn into hash link, even ones to external sites:

After this change, only links to the current instance, as identified by setting.AppURL are turned into hash links:

There is still one notable difference with GitHub where the second link should render like user/repo@<hash>, not <hash> as currently, I would like to fix that here as well.

[wxiaoguang]

Multidomain support #8697

[silverwind]

So what do we check instead of setting.AppURL? Is there a slice of "current app urls" somewhere?

[wxiaoguang]

There is no "current app urls" at the moment.

[silverwind]

We could make server.ROOT_URL accept multiple URLs comma-separated, and then check against all of those.

[silverwind]

Or is there a way to obtain the current URL/Origin in this function? Do we need to pass *http.Request or some context down all the way to this function?

[silverwind]

I guess the only way to make it work based on request URL is to determine the current HTTP request origin (from HTTP headers Host, X-Forwarded-Host, X-Forwarded-Protocol and more) into markup.RenderContext, which will be quite complicated.

It'll certainly be easier to let the user configure multiple server.ROOT_URL.

[silverwind]

I guess this can be used:

gitea/modules/httplib/url.go

Line 58 in eddf875

func GuessCurrentAppURL(ctx context.Context) string {