bare websockets

[benedikt-bartscher]

saves ~11.6 KB gz / ~41 KB raw frontend size (a small js chunk replaces whole socketio)
dropped python deps: wsproto, simple-websocket, python-socketio, python-engineio, bidict
new benchmarks in test_event_transport.py show about 2x performance increase compared to socketio

also migrates AppHarness to granian for consistency. otherwise downstream tests using AppHarness still need uvicorn and wsproto/websockets

[codspeed-hq]

Merging this PR will not alter performance

✅ 27 untouched benchmarks
🆕 4 new benchmarks
⏩ 8 skipped benchmarks¹

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
🆕	Simulation	test_transport_inbound_socketio	N/A	7.9 ms	N/A
🆕	Simulation	test_transport_inbound_websocket	N/A	4.3 ms	N/A
🆕	Simulation	test_transport_outbound_socketio	N/A	17.3 ms	N/A
🆕	Simulation	test_transport_outbound_websocket	N/A	8.6 ms	N/A

---

_{Comparing benedikt-bartscher:make-sio-optional (d106af6) with main (6b44604)}

Footnotes

1. 8 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[greptile-apps]

Greptile Summary

The PR replaces the default Socket.IO transport with a lightweight plain-WebSocket protocol while retaining Socket.IO as an optional transport.

• Adds browser and backend implementations for WebSocket framing, handshakes, heartbeats, reconnection, and event dispatch.
• Makes Socket.IO and Uvicorn dependencies optional and updates Granian/Uvicorn launch behavior.
• Hardens malformed-frame handling and fixes streamed-upload transaction-context reuse.
• Adds transport benchmarks and unit/integration coverage.

Confidence Score: 5/5

The PR appears safe to merge.

No blocking failure remains.

Important Files Changed

Filename	Overview
reflex/event_namespace.py	Implements the plain-WebSocket event namespace and now closes malformed or invalid event streams without leaving the previously reported log-flood paths open.
packages/reflex-base/src/reflex_base/.templates/web/utils/helpers/websocket.js	Adds the browser transport with framing, heartbeat monitoring, connection timeout handling, and documented human-readable durations.
packages/reflex-base/src/reflex_base/.templates/web/utils/state.js	Selects the plain-WebSocket or optional Socket.IO client and adds connection/unmount lifecycle cleanup.
reflex/app.py	Registers the direct WebSocket route by default and lazily initializes the optional Socket.IO transport.
reflex/utils/exec.py	Updates backend launch paths and Uvicorn WebSocket sizing for the new transport configuration.
packages/reflex-base/src/reflex_base/event/processor/event_processor.py	Forks the root event context for streaming deltas so unrelated events cannot attach to a completed future.
pyproject.toml	Moves Socket.IO and Uvicorn support into optional extras and updates the Granian dependency.
tests/units/test_event_namespace.py	Covers WebSocket protocol handling, byte-size enforcement, malformed payload closure, and event routing.

_{Reviews (21): Last reviewed commit: "Merge remote-tracking branch 'upstream/m..." | Re-trigger Greptile}

[cubic-dev-ai]

All reported issues were addressed across 19 files

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All reported issues were addressed across 17 files

<sub>Requires human review: Auto-approval blocked because this review re-detected 1 unresolved issue already reported by Cubic.

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All reported issues were addressed across 4 files (changes from recent commits).

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All reported issues were addressed across 4 files (changes from recent commits).

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All reported issues were addressed across 6 files (changes from recent commits).

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[cubic-dev-ai]

All reported issues were addressed across 6 files (changes from recent commits).

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All reported issues were addressed across 1 file (changes from recent commits).

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All reported issues were addressed across 2 files (changes from recent commits).

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[abulvenz]

I really like this lightweight approach 👍 .
One thing that is dropped, correct me if I see this wrong: under the hood socketio supports HTTP long-polling in case a websocket connection cannot be established (e.g. due to badly configured load balancers, reverse proxies or simply disabled client support). In most cases that should be fixed anyways on server side for performance reasons.

[benedikt-bartscher]

I really like this lightweight approach 👍 . One thing that is dropped, correct me if I see this wrong: under the hood socketio supports HTTP long-polling in case a websocket connection cannot be established (e.g. due to badly configured load balancers, reverse proxies or simply disabled client support). In most cases that should be fixed anyways on server side for performance reasons.

Thanks 🙏

Yes, the new bare websockets implementation does not support http long-polling yet. However one could still choose the old socketio based transport to archive this. Also iirc longpolling was disabled by default anyway, i guess not a lot of users use it. If this is really needed i could add support to our bare websockets implementation as well.