File.download hangs in debug statement indefinately

[gondree]

Describe the bug

File.download hangs when downloading a ~230 MB tgz file. I waited 10+ minutes, but never long enough to see it terminate. I have not tried enough files to produce a minimal working example.

Based on traceback when cancelling mid-operation, the library appears hung in this try/except block:

            try:
                logger.debug("Data: {data}".format(data=pformat(response.json())))
            except ValueError:
                logger.debug("Data: {data}".format(data=pformat(response.text)))

Specifically, its hung performing response.json()

  ...
  File "/Users/gondree/anaconda/envs/hob/lib/python3.6/site-packages/canvasapi/file.py", line 32, in download
    response = self._requester.request("GET", _url=self.url)
  File "/Users/gondree/anaconda/envs/hob/lib/python3.6/site-packages/canvasapi/requester.py", line 226, in request
    logger.debug("Data: {data}".format(data=pformat(response.json())))
  File "/Users/gondree/anaconda/envs/hob/lib/python3.6/site-packages/requests/models.py", line 898, in json
    return complexjson.loads(self.text, **kwargs)
  File "/Users/gondree/anaconda/envs/hob/lib/python3.6/site-packages/requests/models.py", line 858, in text
    encoding = self.apparent_encoding
  File "/Users/gondree/anaconda/envs/hob/lib/python3.6/site-packages/requests/models.py", line 728, in apparent_encoding
    return chardet.detect(self.content)['encoding']
  File "/Users/gondree/anaconda/envs/hob/lib/python3.6/site-packages/chardet/__init__.py", line 38, in detect
    detector.feed(byte_str)
  File "/Users/gondree/anaconda/envs/hob/lib/python3.6/site-packages/chardet/universaldetector.py", line 211, in feed
    if prober.feed(byte_str) == ProbingState.FOUND_IT:
  File "/Users/gondree/anaconda/envs/hob/lib/python3.6/site-packages/chardet/charsetgroupprober.py", line 71, in feed
    state = prober.feed(byte_str)
  File "/Users/gondree/anaconda/envs/hob/lib/python3.6/site-packages/chardet/sbcharsetprober.py", line 79, in feed
    byte_str = self.filter_international_words(byte_str)
  File "/Users/gondree/anaconda/envs/hob/lib/python3.6/site-packages/chardet/charsetprober.py", line 87, in filter_international_words
    buf)
  File "/Users/gondree/anaconda/envs/hob/lib/python3.6/re.py", line 222, in findall
    return _compile(pattern, flags).findall(string)

Expected behavior

The expected behavior is that the file gets downloaded, no matter the size and no matter the contents.

Environment information

• Python version (python --version)

$ python --version
Python 3.6.2 :: Continuum Analytics, Inc.

• CanvasAPI version (pip show canvasapi)

Name: canvasapi
Version: 0.16.0
Summary: API wrapper for the Canvas LMS
Home-page: https://github.com/ucfopen/canvasapi
Author: University of Central Florida - Center for Distributed Learning
Author-email: techrangers@ucf.edu
License: MIT License
Location: /Users/gondree/anaconda/envs/hob/lib/python3.6/site-packages
Requires: requests, pytz, six
Required-by: 

Additional context

I tried to implement a timeout, like:

        ohandler = signal.getsignal(signal.SIGALRM)
        try:
            signal.signal(signal.SIGALRM, lambda a,b: (_ for _ in ()).throw(ValueError))
            signal.alarm(2)
            logger.debug("Data: {data}".format(data=pformat(response.json())))
        except ValueError:
            logger.debug("Data: {data}".format(data=pformat(response.text)))
        finally:
            signal.signal(signal.SIGALRM, ohandler)
            signal.alarm(0)

But, generally, that did not work correctly.

The simplest fix for me was avoiding the operations when not debugging:

        if logger.isEnabledFor(logging.DEBUG):
            try:
                logger.debug("Data: {data}".format(data=pformat(response.json())))
            except ValueError:
                logger.debug("Data: {data}".format(data=pformat(response.text)))

This solved my problem. It would not be ideal if you ever needed to debug in a situation involving one of these problematic downloads. Reporting in hope that this, or a more clever fix, can be incorporated.