Registry / http-networking / aiohttp-sse

aiohttp-sse

library2.2.0pypypi✓ verified 85d ago

aiohttp-sse provides server-sent events support for aiohttp. It allows building real-time web applications where the server pushes updates to clients over a single HTTP connection. The current version is 2.2.0, and it has a relatively active release cadence with several updates per year, focusing on Python and aiohttp compatibility.

http-networking web-framework

pip install aiohttp-sse

github ↗package ↗

INSTALL

IMPORT

SIG · AIOHTTP-SSE

aiohttp-sse

http-networkingpythonv2.2.0

Install

4.5s avg

Import

652ms

Disk

27MB

Pass rate

10/ 10

Env Coverage10 / 10

glibc

3.9–3.13

musl

3.9–3.13

Install & Compatibility

Where this runs

tested against v2.2.0 · pip install

no network on importno background threads

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

py 3.10–3.920 runs

installs and imports cleanly · install 0.0s · import 0.689s · 27.2MB

glibc

py 3.10–3.920 runs

installs and imports cleanly · install 4.5s · import 0.616s · 29MB

27MB installed

● package 27MB

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

sse_response

✓ from aiohttp_sse import sse_response

EventSourceResponse

✓ from aiohttp_sse import EventSourceResponse

This quickstart sets up an aiohttp web server that serves an HTML page. The HTML page contains JavaScript that connects to a '/hello' endpoint via Server-Sent Events. The '/hello' endpoint uses `aiohttp-sse`'s `sse_response` context manager to continuously send the current server time to the connected client.

import asyncio import json from datetime import datetime from aiohttp import web from aiohttp_sse import sse_response async def hello(request: web.Request) -> web.StreamResponse: async with sse_response(request) as resp: # Optional: send an initial comment to stop browser loading spinner await resp.send(None, event='comment', data='connected') while resp.is_connected(): time_dict = {"time": f"Server Time : {datetime.now()}"} data = json.dumps(time_dict, indent=2) print(data) await resp.send(data) await asyncio.sleep(1) return resp async def index(_request: web.Request) -> web.Response: html = """ <html> <body> <script> var eventSource = new EventSource("/hello"); eventSource.addEventListener("message", event => { document.getElementById("response").innerText = event.data; }); </script> <h1>Response from server:</h1> <div id="response"></div> </body> </html> """ return web.Response(text=html, content_type="text/html") app = web.Application() app.router.add_route("GET", "/hello", hello) app.router.add_route("GET", "/", index) if __name__ == '__main__': web.run_app(app, host="127.0.0.1", port=8080)

Debug

Known issues

breakingPython version support has been frequently dropped in major and minor releases. Version 2.2.0 dropped Python 3.7, and 2.1.0 dropped Python 3.6 support. Ensure your Python environment meets the `>=3.8` requirement for current versions.

fix

Upgrade Python to 3.8 or newer, or pin to an older `aiohttp-sse` version compatible with your Python environment.

affects: <2.2.0

breakingMajor versions of `aiohttp-sse` are tied to specific `aiohttp` versions. Version 2.0.0 introduced compatibility with `aiohttp 3.0+`, while older versions like 1.0.0 required `aiohttp2+`, and 0.1.0 was for `aiohttp<2.0`. Mismatched `aiohttp` versions can lead to runtime errors.

fix

Check the `aiohttp-sse` release notes for the exact `aiohttp` version compatibility. Upgrade both `aiohttp-sse` and `aiohttp` to compatible versions.

affects: <2.0.0

gotchaBrowsers keep the tab's loading spinner active as long as an SSE connection remains open, which can be confusing for users.

fix

Send an initial 'comment' event (e.g., `await resp.send(None, event='comment', data='connected')`) after establishing the SSE connection. This signals the browser that the connection is live and usually stops the spinner.

affects: All

gotchaPrior to v2.2.0, specifically on Python 3.11+, the `EventSourceResponse.wait()` method could swallow user cancellation, making it difficult to gracefully shut down SSE streams.

fix

Upgrade to `aiohttp-sse` version 2.2.0 or newer to benefit from the fix for `EventSourceResponse.wait()` cancellation behavior on Python 3.11+.

affects: <2.2.0

gotcha`aiohttp` itself does not natively provide client-side Server-Sent Events parsing. Users attempting to consume `aiohttp-sse` streams with a plain `aiohttp.ClientSession` might find parsing challenging.

fix

For client-side SSE consumption, consider using dedicated libraries like `aiohttp-sse-client` or `aiosseclient` built on top of `aiohttp`, or implement custom parsing logic.

affects: All

gotchaWeb browsers often impose a limit (e.g., 6) on the number of concurrent HTTP connections to a single domain. Exceeding this limit with multiple SSE connections can cause new requests to hang or time out.

fix

Design client-side applications to manage and reuse SSE connections efficiently. Avoid opening an excessive number of simultaneous SSE streams from the same client to the same server. Adjusting browser settings (e.g., `network.http.speculative-parallel-limit` in Firefox) can also be done for testing, but is not a general solution for users.

affects: All

Errors

Common errors & fixes

ModuleNotFoundError: No module named 'aiohttp_sse'

The 'aiohttp-sse' package is not installed in the Python environment.

fix

Install the package using pip: 'pip install aiohttp-sse'.

ImportError: cannot import name 'EventSourceResponse' from 'aiohttp_sse'

The 'EventSourceResponse' class is not available in the 'aiohttp_sse' module.

fix

Use 'sse_response' instead: 'from aiohttp_sse import sse_response'.

AttributeError: 'EventSourceResponse' object has no attribute 'send'

The 'EventSourceResponse' object does not have a 'send' method.

fix

Use 'sse_response' which provides the 'send' method: 'from aiohttp_sse import sse_response'.

ModuleNotFoundError: No module named 'aiohttp-sse'

The `aiohttp-sse` library is not installed in your Python environment or is not accessible on the Python path.

fix

Install the library using pip: `pip install aiohttp-sse`

AttributeError: module 'aiohttp' has no attribute 'ClientSession'

This typically occurs when you have a file named `aiohttp.py` in your project directory, which shadows the actual `aiohttp` library, or if you are trying to use an outdated API for `aiohttp` client requests.

fix

Rename any local file named `aiohttp.py` to something else (e.g., `my_aiohttp_app.py`). Ensure you are using `aiohttp.ClientSession()` for client requests, as direct `aiohttp.get()` was deprecated.

Upgrade

Version history

2.2.0latest on PyPI · released Feb 29, 2024

Audit

Dependencies

aiohttprequiredCore dependency for web server functionality. Requires aiohttp 3+ for current versions.

pythonrequiredRequires Python 3.8+ as of version 2.2.0.

Agent activity

44 hits · last 30 days

node

OpenAI (training)

Resources

githubhttps://github.com/aio-libs/aiohttp_sse ↗

packagehttps://pypi.org/project/aiohttp-sse/ ↗