FileResponse sends empty chunked body when returning 304

[es1024]

Long story short

FileResponse (and by extension, add_static) may return Transfer-Encoding: chunked and the empty chunked body when returning a 304 Not Modified, in violation of RFC 2616 §10.3.5, which states: "The 304 response MUST NOT contain a message-body, and thus is always terminated by the first empty line after the header fields."

Expected behaviour

A 304 response with no body.

Actual behaviour

A 304 response with Transfer-Encoding: chunked and a 1-byte body (0).

Steps to reproduce

1. Run this with an empty index.html in the same directory:

from aiohttp import web
from pathlib import Path

app = web.Application()
app.router.add_static('/', Path(__file__).parent)
web.run_app(app, port=8080)

2. Send an HTTP/1.1 request with an If-Modified-Since that triggers a 304 Not Modified, e.g.

# nc localhost 8080
GET /index.html HTTP/1.1
If-Modified-Since: Fri, 28 Jul 2017 18:42:00 GMT

The response will be something like:

HTTP/1.1 304 Not Modified
Transfer-Encoding: chunked
Content-Type: application/octet-stream
Date: Fri, 28 Jul 2017 18:42:34 GMT
Server: Python/3.6 aiohttp/2.2.3

0

Your environment

This is using aiohttp 2.2.3, the newest version at this time.

[asvetlov]

Sounds reasonable.
Would you provide a Pull Request @es1024 ?

[cecton]

Fixed by cc614ca

[lock]

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If you feel like there's important points made in this discussion, please include those exceprts into that [new issue].
[new issue]: https:/aio-libs/aiohttp/issues/new