Add ETag support for StaticFile.fromUrl

[diogocanut]

This PR brings changes made at #6621 and #4879 solving Issue #2826 .

[satorg]

Thank you for the PR!

I am a bit concerned though about using java.net's URL and URLConnection as a part of public APIs.
Is it somewhat necessary, or can it be switched to http4s Uri and maybe fs2.net capabilities ?

[armanbilge]

Is it somewhat necessary

I cannot remember why at this moment, but I think for some reason it was.

or can it be switched to http4s Uri and maybe fs2.net capabilities ?

Well, yes and no 😂 in theory, absolutely yes. In practice, it would require implementing all the protocols that URLConnection supports ... such as HTTP ... and then we end up with Ember lol.

[satorg]

I mean, perhaps it could be ok to use it internally, when necessary... Just wondering, if it is possible to avoid exposing it in APIs.. Sorry, I haven't wrapped my head around the case yet, so perhaps I'm saying silly things. I just get triggered to java.net.URL and a lot of blocking calls inside 😊

[armanbilge]

Not at all, it's a very good question, it's a suspicious looking API. I must have been convinced at some point, when I was reviewing the previous PR, but I'm having a hard time remembering why we needed it.