Add support for multipart subscriptions

[patrick91]

This is a new protocol created by Apollo (and supported by Apollo Client)

TODO

• Add support for this in all HTTP integrations that support subscriptions
• Send a ping every 5 seconds (an empty {} is enough)
• Add a proper way to check if an operation is a subscription in our Async HTTP View
• Make sure that the returned responses is actually being streamed
• Return proper error when trying to run a subscription and it's not supported
• Add docs (using a proxy breaks the disconnection)

Protocol docs: https://www.apollographql.com/docs/router/executing-operations/subscription-multipart-protocol/

[codecov]

Codecov Report

Attention: Patch coverage is 91.42857% with 21 lines in your changes missing coverage. Please review.

Project coverage is 96.79%. Comparing base (08db7f7) to head (20e8bf7).
Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3076      +/-   ##
==========================================
- Coverage   96.82%   96.79%   -0.04%     
==========================================
  Files         514      517       +3     
  Lines       33322    33528     +206     
  Branches     5528     5575      +47     
==========================================
+ Hits        32263    32452     +189     
- Misses        835      847      +12     
- Partials      224      229       +5     

[codspeed-hq]

CodSpeed Performance Report

Merging #3076 will degrade performances by 28.11%

_{Comparing feature/multipart (20e8bf7) with main (08db7f7)}

Summary

❌ 1 regressions
✅ 14 untouched benchmarks

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Benchmarks breakdown

	Benchmark	main	feature/multipart	Change
❌	test_execute	589.2 ms	819.6 ms	-28.11%

[github-actions]

Hi 👋 You can find a preview of the docs here:

https://strawberry.rocks/docs/pr/3076/integrations/index

[patrick91]

~~one thing I'm not sure about this is handling client closing the connections 🤔 ~~

edit: this seems to be handled by fastapi, I need to check django and others, also I was using next.js' proxy for this, and that was preventing the disconnect message from being sent

[patrick91]

🔥

[DoctorJohn]

This extends the Schema.execute method to handle subscriptions. Im wondering whether this was intentional since we already have a separate Schema.subscribe method? 👀 @patrick91 @bellini666

I noticed this change while upgrading to the latest version. In my codebase mypy now complains everywhere that Schema.execute can now return both ExecutionResult and SubscriptionExecutionResult. Before Schema.execute could only return an ExecutionResult while subscriptions were handled by Schema.subscribe.

[patrick91]

that was poor design on my part, it will be fixed in #3554 😊