Mask JSONDecodeError raised by bad server response data

[jyu00]

What is the expected behavior?

Occasionally the server would return invalid JSON data. In which case a JSONDecodeError is raised:

  File "/home/travis/build/jyu00/qiskit-ibmq-provider/qiskit/providers/ibmq/api/clients/account.py", line 90, in backend_status
    return self.client_api.backend(backend_name).status()
  File "/home/travis/build/jyu00/qiskit-ibmq-provider/qiskit/providers/ibmq/api/rest/backend.py", line 82, in status
    response = self.session.get(url).json()
  File "/home/travis/virtualenv/python3.8.0/lib/python3.8/site-packages/requests/models.py", line 897, in json
    return complexjson.loads(self.text, **kwargs)
  File "/opt/python/3.8.0/lib/python3.8/json/__init__.py", line 357, in loads
    return _default_decoder.decode(s)
  File "/opt/python/3.8.0/lib/python3.8/json/decoder.py", line 337, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File "/opt/python/3.8.0/lib/python3.8/json/decoder.py", line 355, in raw_decode
    raise JSONDecodeError("Expecting value", s, err.value) from None
json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)

This can be confusing to the user, who might just be doing a normal job.cancel() or backend.status(). We should wrap this with something like RequestsApiError and a message saying invalid data received from the server. Or just retry the request as that usually works.

[jyu00]

There is supposedly an API fix coming.

[jyu00]

This hasn't happened in a while since the server deployed their fix. Closing.