Enable Websocket compression for Netty

[TheAntimist]

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Helpful things

Fixes

Fixes #10863 and #4186

Purpose

Enable WebSocket Compression for Netty, using the WebSocketServerCompressionHandler. Adds the Netty 4.x WebSocketServerCompressionHandler to the chain of Netty's codecs.

Tests have been added to the netty-reactive-streams repository, as that seemed the correct place to add them. Let me know in case there's any concerns over this.

Tests

Added here: playframework/netty-reactive-streams#126

Background Context

This had to be added here, because if I added it to HttpStreamsServerHandler it would be too late for processing, and Compression would not get enabled. This is because it requires detecting of the Websocket Upgrade requests to enable Websocket Extension Headers.

References

From the Netty Websocket examples: https://github.com/netty/netty/blob/4.1/example/src/main/java/io/netty/example/http/websocketx/server/WebSocketServerInitializer.java#L47

[TheAntimist]

@mkurz Hopefully this looks good, let me know in case of any changes or questions.

[mkurz]

Thanks! The test in the netty-reactive-streams repo is broken.
Adding tests in the netty-reactive-streams repo however does not test this change here. I mean, it shows nicely which effect adding WebSocketServerCompressionHandler has, however not sure if it's worth also adding a scripted test here too, like http-backend-netty or http-backend-netty-channel-options.

[TheAntimist]

The test in the netty-reactive-streams repo is broken.

Fixed, I was using Java 11, and missed the final requirement for the variables.

I mean, it shows nicely which effect adding WebSocketServerCompressionHandler has, however not sure if it's worth also adding a scripted test here too, like http-backend-netty or http-backend-netty-channel-options.

I agree. Honestly, I was not certain where this would be placed. I will add a test similar to the http-backend as it would provide a more holistic view.

[TheAntimist]

FYI, got caught up in some work but the integration test is a WIP and should be done by this weekend.

[mkurz]

No hurry, I am busy with other stuff this week as well 😉

[mkurz]

@TheAntimist are you still willing to work on this pull request?

[TheAntimist]

@mkurz Apologies I got busy with some other personal things and also an internship in between. I cannot find the work that I had completed on it for some reason.

I can continue working on it now. I have a question on the IntegrationTest, would you want me to modify the controllers for the http-netty-backend here or do you want me to create one seperate integration test for just this?

[mkurz]

You can make use of that existing scripted test. E.g. you can add new routes here and new action methods here, then you should be able to write the test(s) needed. Be aware that here we talk about scripted tests, so you need to run publishLocal before running them with scripted play-sbt-plugin/http-backend-netty. I also highly recommend to set (ThisBuild / version) := "2.9.0-SNAPSHOT" within the build.sbt file of your play repo clone (before running sbt). This way you makes sure each time you restart sbt and start running scripted ... again the locally publish artifact will be found (because right now the local published artifacts contain the date and time, like 2.8.1+1835-919b5bda+20220912-1743-SNAPSHOT, which of course would change as soon as you reload sbt).

Actually... As an alternative to the scripted test you could add a test here as well if you prefer that:
https://github.com/playframework/playframework/blob/main/core/play-integration-test/src/it/scala/play/it/http/websocket/WebSocketSpec.scala

[mkurz]

Could not re-open this pull request, so I had to create a new one:

• Enable Websocket compression for Netty #12477