[THRIFT-5467] CannotSendHeader exception with 0.15

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.15.0
• Fix Version/s: 0.17.0
• Component/s: Python - Library
• Assignee: Jens Geyer
• Reporter: Jeffrey Tolar
• Created: 01/Oct/21 21:52
• Updated: 26/Oct/22 23:46
• Resolved: 21/Feb/22 18:22

Description

We recently started using thrift 0.15.0 after it was pushed to PyPI last week; previously, we were using 0.13.
Since then, we've been receiving the following exception:

# /tmp/thrift-error/bin/python test.py
Traceback (most recent call last):
  File "test.py", line 16, in <module>
    transport.flush()
  File "/tmp/thrift-error/lib/python3.8/site-packages/thrift/transport/THttpClient.py", line 191, in flush
    self.__http.putheader('Cookie', self.headers['Set-Cookie'])
  File "/opt/python/lib/python3.8/http/client.py", line 1217, in putheader
    raise CannotSendHeader()
http.client.CannotSendHeader

Here's the test.py:

test.py

import thrift.transport.THttpClient

URL = 'https://....'
CA_FILE = '...'
CERT_FILE = '...'
KEY_FILE = '...'

transport = thrift.transport.THttpClient.THttpClient(
    uri_or_host=URL,
    cafile=CA_FILE,
    cert_file=CERT_FILE,
    key_file=KEY_FILE
)

transport.flush()

This appears to be a regression from THRIFT-5165 and https://github.com/apache/thrift/pull/2086.

Based on the python source for http.client, HTTPConnection.putheader can only be called after a request has been started, and before it's been sent. (There's a state diagram at the top of that file).

The current THttpClient.py calls HTTPConnection.putheader('Cookie', ...) after reading the response (and before it starts another request) - based on the code for both projects, it looks like if the server returns a Set-Cookie header, the client will always fail with the CannotSendHeader exception.

Issue Links

• links to: GitHub Pull Request #2491