[FIXED] ValueError: check_hostname requires server_hostname using Fiddler 4

Issue

This question just recently posted has some useful answers, but it's not the same as mine. I'm running urllib3 1.26.4 and Python 3.7 from an ArcGIS Pro Notebook. I also have Fiddler 4 open because I want to track web traffic while troubleshooting a script. I only get the following error when I have Fiddler open. If I close Fiddler I get <Response [200]>. Is it not possible to use the requests module with Fiddler open? I'm new to Fiddler.

Truncated script:

import requests

#url
idph_data = 'https://idph.illinois.gov/DPHPublicInformation/api/covidVaccine/getVaccineAdministrationCurrent'
#headers
headers = {'user-agent': 'Mozilla/5.0'}

response = requests.get(idph_data, headers=headers, verify=True)

Error:

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
In  [35]:
Line 4:     response = requests.get(idph_data,verify=True)

File C:\Program Files\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\lib\site-packages\requests\api.py, in get:
Line 76:    return request('get', url, params=params, **kwargs)

File C:\Program Files\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\lib\site-packages\requests\api.py, in request:
Line 61:    return session.request(method=method, url=url, **kwargs)

File C:\Program Files\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\lib\site-packages\requests\sessions.py, in request:
Line 542:   resp = self.send(prep, **send_kwargs)

File C:\Program Files\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\lib\site-packages\requests\sessions.py, in send:
Line 655:   r = adapter.send(request, **kwargs)

File C:\Program Files\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\lib\site-packages\requests\adapters.py, in send:
Line 449:   timeout=timeout

File C:\Program Files\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\lib\site-packages\urllib3\connectionpool.py, in urlopen:
Line 696:   self._prepare_proxy(conn)

File C:\Program Files\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\lib\site-packages\urllib3\connectionpool.py, in _prepare_proxy:
Line 964:   conn.connect()

File C:\Program Files\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\lib\site-packages\urllib3\connection.py, in connect:
Line 359:   conn = self._connect_tls_proxy(hostname, conn)

File C:\Program Files\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\lib\site-packages\urllib3\connection.py, in _connect_tls_proxy:
Line 506:   ssl_context=ssl_context,

File C:\Program Files\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\lib\site-packages\urllib3\util\ssl_.py, in ssl_wrap_socket:
Line 432:   ssl_sock = _ssl_wrap_socket_impl(sock, context, tls_in_tls)

File C:\Program Files\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\lib\site-packages\urllib3\util\ssl_.py, in _ssl_wrap_socket_impl:
Line 474:   return ssl_context.wrap_socket(sock)

File C:\Program Files\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\lib\ssl.py, in wrap_socket:
Line 423:   session=session

File C:\Program Files\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\lib\ssl.py, in _create:
Line 827:   raise ValueError("check_hostname requires server_hostname")

ValueError: check_hostname requires server_hostname
---------------------------------------------------------------------------

Solution

I've updated to requests v. 2.7.0, the latest, and I'm no longer receiving the error. If it was a version-specific issue related to v. 2.25.1, which was what I was using, I'm not sure. I haven't came across any evidence of that.

In a Windows command prompt in the same directory as my Python executable:

python -m pip install requests==2.7.0

Now if I run my original script with Fiddler capturing, I get a HTTP status of 200 and my script no longer gives me the error.

Answered By - Pfalbaum