classification
Title: http.client no longer sends HTTP request in one TCP package
Type: behavior Stage:
Components: Library (Lib) Versions: Python 3.8, Python 3.7, Python 3.6
process
Status: open Resolution:
Dependencies: Superseder:
Assigned To: Nosy List: benjamin.peterson, christian.heimes, orsenthil
Priority: normal Keywords: 3.5regression

Created on 2018-03-13 12:06 by christian.heimes, last changed 2018-03-13 17:40 by orsenthil.

Messages (1)
msg313743 - (view) Author: Christian Heimes (christian.heimes) * (Python committer) Date: 2018-03-13 12:06
https://bugs.python.org/issue23302 changed how http.client sends request. endheaders() no longer sends header and message body in one TCP package if the total payload is smaller than TCP max segment size. https://github.com/python/cpython/blob/3.5/Lib/http/client.py#L934-L936 uses two send calls to send header and body. This causes very simple HTTP servers in embedded devices to fail.

Matthew Garrett noticed the bug, see https://twitter.com/mjg59/status/972985566387032064 / https://twitter.com/mjg59/status/973000950439817217

We should try to send requests as one TCP package again. TCP_CORK may do the trick. Or we should fix our custom implementation of send. It has multiple issues, e.g. a fixed buffer. The buffer size is suboptimal for small MTU and jumbo frames.
History
Date User Action Args
2018-03-13 17:40:23orsenthilsetnosy: + orsenthil
2018-03-13 12:06:43christian.heimescreate