Metadata-Version: 2.1
Name: sse-starlette
Version: 1.2.1
Summary: "SSE plugin for Starlette"
Home-page: https://github.com/sysid/sse-starlette
Author: sysid
Author-email: sysid@gmx.de
Classifier: Development Status :: 5 - Production/Stable
Classifier: Environment :: Web Environment
Classifier: Intended Audience :: Developers
Classifier: License :: OSI Approved :: BSD License
Classifier: Operating System :: OS Independent
Classifier: Programming Language :: Python :: 3
Classifier: Programming Language :: Python :: 3.9
Requires-Python: >=3.8
Description-Content-Type: text/markdown
License-File: LICENSE
License-File: AUTHORS
Requires-Dist: starlette

# Server Sent Events for [Starlette](https://github.com/encode/starlette) and [FastAPI](https://fastapi.tiangolo.com/)

[![PyPI Version][pypi-image]][pypi-url]
[![Build Status][build-image]][build-url]
[![Code Coverage][coverage-image]][coverage-url]

Background: https://sysid.github.io/sse/

Installation:

```shell
pip install sse-starlette
```

Usage:

```python
import asyncio
import uvicorn
from starlette.applications import Starlette
from starlette.routing import Route
from sse_starlette.sse import EventSourceResponse

async def numbers(minimum, maximum):
    for i in range(minimum, maximum + 1):
        await asyncio.sleep(0.9)
        yield dict(data=i)

async def sse(request):
    generator = numbers(1, 5)
    return EventSourceResponse(generator)

routes = [
    Route("/", endpoint=sse)
]

app = Starlette(debug=True, routes=routes)

if __name__ == "__main__":
    uvicorn.run(app, host="0.0.0.0", port=8000, log_level='info')
```

Output:
![output](output.png)

**Caveat:** SSE streaming does not work in combination with [GZipMiddleware](https://github.com/encode/starlette/issues/20#issuecomment-704106436).

Be aware that for proper server shutdown your application must stop all
running tasks (generators). Otherwise you might experience the following warnings
at shutdown: `Waiting for background tasks to complete. (CTRL+C to force quit)`.

Client disconnects need to be handled in your Request handler (see example.py):
```python
async def endless(req: Request):
    async def event_publisher():
        i = 0
        try:
          while True:
              i += 1
              yield dict(data=i)
              await asyncio.sleep(0.2)
        except asyncio.CancelledError as e:
          _log.info(f"Disconnected from client (via refresh/close) {req.client}")
          # Do any other cleanup, if any
          raise e
    return EventSourceResponse(event_publisher())
```

Run the tests:
```python
make test
```

## Special use cases
### Fan out Proxies
Fan out proxies usually rely on response being cacheable. To support that, you can set the value of `Cache-Control`.
For example:
```python
return EventSourceResponse(
        generator(), headers={"Cache-Control": "public, max-age=29"}
    )
```

## Changelog
[CHANGELOG.md](https://github.com/sysid/sse-starlette/blob/master/CHANGELOG.md)

<!-- Badges -->

[pypi-image]: https://badge.fury.io/py/sse-starlette.svg
[pypi-url]: https://pypi.org/project/sse-starlette/
[build-image]: https://github.com/sysid/sse-starlette/actions/workflows/build.yml/badge.svg
[build-url]: https://github.com/sysid/sse-starlette/actions/workflows/build.yml
[coverage-image]: https://codecov.io/gh/sysid/sse-starlette/branch/master/graph/badge.svg
[coverage-url]: https://codecov.io/gh/sysid/sse-starlette

Copyright © 2020, [sysid](https://sysid.github.io/).
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

* Redistributions of source code must retain the above copyright notice, this
  list of conditions and the following disclaimer.

* Redistributions in binary form must reproduce the above copyright notice,
  this list of conditions and the following disclaimer in the documentation
  and/or other materials provided with the distribution.

* Neither the name of the copyright holder nor the names of its
  contributors may be used to endorse or promote products derived from
  this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
