Make broadcaster dependencies optional

[nneskildsf]

An option is available for each backend as well as an "all" option which gets you everything.

• Install without options: pip install fastapi_websocket_pubsub
• Install with Redis broadcaster: pip install fastapi_websocket_pubsub[redis]
• Install with Postgres broadcaster: pip install fastapi_websocket_pubsub[postgres]
• Install with Kafka broadcaster: pip install fastapi_websocket_pubsub[kafka]
• Install with all options: pip install fastapi_websocket_pubsub[all]

This PR aims to close #57. I made this PR because it will enable me to install fastapi_websocket_pubsub on python:3.13-alpine Docker image without first installing build-base and zlib-dev.

Thanks a ton for this library. It's been quite useful and I appreciate that you maintain it and offer it to the community.

Br Eskild

[nneskildsf]

Ping @orweis :-)

[orweis]

Ping @orweis :-)

Tests fail

I currently don't have the CPU to look into this.

[nneskildsf]

Tests fail

I currently don't have the CPU to look into this.

Hi

I have improved the PR by:

• Adding a note to the readme about installing the optional backends
• Only running tests using optional backends if these are installed
• Installing all optional modules when doing automated testing (requirements-dev.txt)

Unfortunately tests in tests/server_notifier_callback_test.py and it their failure appears to be unrelated to this PR. All other tests run successfully AFAIK.

I don't mind looking into why they fail and potentially fixing it but I think it is outside the scope of this PR. What do you think?

Br Eskild

[nneskildsf]

Apparently the tests failed because the websockets package changed the API since version 11.0 (latest is 15.0.1 at the time of writing). Additional headers should now be supplied via additional_headers and not extra_headers. I have updated the PR to fix this, even though I do believe it is outside the scope of it.

All tests pass locally with websockets>=14.0 as well as through Github Actions.

[danyi1212]

🚨 Breaking Changes Added

LGTM