What are the differences between the urllib, urllib2, urllib3 and requests module?

Question

In Python, what are the differences between the urllib, urllib2, urllib3 and requests modules? Why are there three? They seem to do the same thing...

Answer 1

To get the content of a url:

try: # Try importing requests first.
    import requests
except ImportError: 
    try: # Try importing Python3 urllib
        import urllib.request
    except AttributeError: # Now importing Python2 urllib
        import urllib


def get_content(url):
    try:  # Using requests.
        return requests.get(url).content # Returns requests.models.Response.
    except NameError:  
        try: # Using Python3 urllib.
            with urllib.request.urlopen(index_url) as response:
                return response.read() # Returns http.client.HTTPResponse.
        except AttributeError: # Using Python3 urllib.
            return urllib.urlopen(url).read() # Returns an instance.

It's hard to write Python2 and Python3 and request dependencies code for the responses because they urlopen() functions and requests.get() function return different types:

• Python2 urllib.request.urlopen() returns a http.client.HTTPResponse
• Python3 urllib.urlopen(url) returns an instance
• Request request.get(url) returns a requests.models.Response