New submission from Martin Panter:
The AbstractHTTPHandler.do_open() method creates a HTTPConnection object but
does not save it anywhere. This means a ResourceWarning is eventually
triggered, at least when the HTTP server leaves the the connection open.
Demonstration code:
from urllib.request import urlopen
with urlopen("http://localhost";) as response: response.read()
When I used the above code, the warning did not trigger until I forced a
garbage collection:
import gc; gc.collect()
Output:
__main__:1: ResourceWarning: unclosed <socket.socket object, fd=3, family=2,
type=1, proto=6>
Alternatively, you can add a line to the bottom of the do_open() method:
r.msg = r.reason
del h; import gc; gc.collect() # Add this to force warning
return r
When the warning happens without forced garbage collection, it tends to happen
here:
/usr/lib/python3.3/socket.py:370: ResourceWarning: unclosed <socket.socket
object, fd=3, family=2, type=1, proto=6>
self._sock = None
I tested by using the “socat” CLI program and supplying a chunked HTTP
response, without immediately closing the connection at the server end. Using
the Content-length header also seems to trigger the issue.
$ sudo socat -d TCP-LISTEN:www,reuseaddr,crnl READLINE
GET / HTTP/1.1
Accept-Encoding: identity
Host: localhost
Connection: close
User-Agent: Python-urllib/3.3
<HTTP response start>
HTTP/1.1 200 OK
Transfer-encoding: chunked
0
<HTTP response end>
If the server leaves the connection open, it only seems to get closed when
Python garbage-collects the socket and closes it. Perhaps the connection should
be explicitly closed when the urlopen() response object is closed. But I guess
that would require wrapping the HTTPResponse object to add to the close
behaviour.
----------
components: Library (Lib)
messages: 202404
nosy: vadmium
priority: normal
severity: normal
status: open
title: ResourceWarning when urlopen() forgets the HTTPConnection object
versions: Python 3.2, Python 3.3
_______________________________________
Python tracker <rep...@bugs.python.org>
<http://bugs.python.org/issue19524>
_______________________________________
_______________________________________________
Python-bugs-list mailing list
Unsubscribe:
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
