Python requests exception handling

Question

Assuming you did import requests, you want requests.ConnectionError. ConnectionError is an exception defined by requests. See the API documentation here.

Thus the code should be :

try:
   requests.get('http://www.google.com')
except requests.ConnectionError:
   # handle the exception

As per the documentation, I have added the below points:-

1. In the event of a network problem (refused connection e.g internet issue), Requests will raise a ConnectionError exception.

   try:
      requests.get('http://www.google.com')
   except requests.ConnectionError:
      # handle ConnectionError the exception
   

2. In the event of the rare invalid HTTP response, Requests will raise an HTTPError exception. Response.raise_for_status() will raise an HTTPError if the HTTP request returned an unsuccessful status code.

   try:
      r = requests.get('http://www.google.com/nowhere')
      r.raise_for_status()
   except requests.exceptions.HTTPError as err:
      #handle the HTTPError request here
   

3. In the event of times out of request, a Timeout exception is raised.

   You can tell Requests to stop waiting for a response after a given number of seconds, with a timeout arg.

   requests.get('https://github.com/', timeout=0.001)
   # timeout is not a time limit on the entire response download; rather, 
   # an exception is raised if the server has not issued a response for
   # timeout seconds
   

4. All exceptions that Requests explicitly raises inherit from requests.exceptions.RequestException. So a base handler can look like,

   try:
      r = requests.get(url)
   except requests.exceptions.RequestException as e:
      # handle all the errors here
   

Actually, there are much more exceptions that requests.get() can generate than just ConnectionError. Here are some I've seen in production:

from requests import ReadTimeout, ConnectTimeout, HTTPError, Timeout, ConnectionError

try:
    r = requests.get(url, timeout=6.0)
except (ConnectTimeout, HTTPError, ReadTimeout, Timeout, ConnectionError):
    continue

for clarity, that is

except requests.ConnectionError:

NOT

import requests.ConnectionError

 

You can also catch a general exception (although this isn't recommended) with

except Exception: