Let us try to pretend to log in to a popular code-sharing website, https://bitbucket.org/. We would like to submit the login information on the login page, https://bitbucket.org/account/signin/?next=/. The following screenshot shows the login page:

So, we note down the form element IDs and decide which fake values should be submitted. We access this page the first time, and the next time, we access the home page to observe what cookies have been set up.

Listing 4.3 explains extracting cookie information as follows:

#!/usr/bin/env python 
# Python Network Programming Cookbook -- Chapter - 4 
# This program requires Python 3.5.2 or any later version 
# It may run on any other version with/without modifications. 
# 
# Follow the comments inline to make it run on Python 2.7.x. 
 
import http.cookiejar  
# Comment out the above line and uncomment the below for Python 2.7.x. 
#import cookielib  
 
import urllib 
 
# Uncomment the below line for Python 2.7.x. 
#import urllib2 
 
 
ID_USERNAME = 'id_username' 
ID_PASSWORD = 'id_password' 
USERNAME = '[email protected]' 
PASSWORD = 'mypassword' 
LOGIN_URL = 'https://bitbucket.org/account/signin/?next=/' 
NORMAL_URL = 'https://bitbucket.org/' 
 
def extract_cookie_info(): 
    """ Fake login to a site with cookie""" 
    # setup cookie jar 
 
    cj = http.cookiejar.CookieJar() 
    # Comment out the above line and uncomment the below for Python 2.7.x. 
    #cj = cookielib.CookieJar() 
 
    login_data = urllib.parse.urlencode({ID_USERNAME : USERNAME,
                  ID_PASSWORD : PASSWORD}).encode("utf-8") 
    # Comment out the above line and uncomment the below for Python 2.7.x. 
    #login_data = urllib.urlencode({ID_USERNAME : USERNAME,
                                    ID_PASSWORD : PASSWORD}) 
 
    # create url opener 
 
    opener = urllib.request.
    build_opener(urllib.request.HTTPCookieProcessor(cj)) 
    # Comment out the above line and uncomment the below for Python 2.7.x. 
    #opener = urllib2.build_opener(urllib2.HTTPCookieProcessor(cj)) 
 
    resp = opener.open(LOGIN_URL, login_data) 
 
    # send login info  
    for cookie in cj: 
        print ("----First time cookie: %s --> %s"
         %(cookie.name, cookie.value)) 
    print ("Headers: %s" %resp.headers) 
 
    # now access without any login info 
    resp = opener.open(NORMAL_URL) 
    for cookie in cj: 
        print ("++++Second time cookie: %s --> %s"
                %(cookie.name, cookie.value)) 
     
    print ("Headers: %s" %resp.headers) 
 
if __name__ == '__main__': 
    extract_cookie_info() 

Running this recipe results in the following output:

$ python 4_3_extract_cookie_information.py 
----First time cookie: bb_session --> aed58dde1228571bf60466581790566d
Headers: Server: nginx/1.2.4
Date: Sun, 05 May 2013 15:13:56 GMT
Content-Type: text/html; charset=utf-8
Content-Length: 21167
Connection: close
X-Served-By: bitbucket04
Content-Language: en
X-Static-Version: c67fb01467cf
Expires: Sun, 05 May 2013 15:13:56 GMT
Vary: Accept-Language, Cookie
Last-Modified: Sun, 05 May 2013 15:13:56 GMT
X-Version: 14f9c66ad9db
ETag: "3ba81d9eb350c295a453b5ab6e88935e"
X-Request-Count: 310
Cache-Control: max-age=0
Set-Cookie: bb_session=aed58dde1228571bf60466581790566d; expires=Sun, 19-May-2013 15:13:56 GMT; httponly; Max-Age=1209600; Path=/; secure
    
Strict-Transport-Security: max-age=2592000
X-Content-Type-Options: nosniff
    
++++Second time cookie: bb_session --> aed58dde1228571bf60466581790566d
Headers: Server: nginx/1.2.4
Date: Sun, 05 May 2013 15:13:57 GMT
Content-Type: text/html; charset=utf-8
Content-Length: 36787
Connection: close
X-Served-By: bitbucket02
Content-Language: en
X-Static-Version: c67fb01467cf
Vary: Accept-Language, Cookie
X-Version: 14f9c66ad9db
X-Request-Count: 97
Strict-Transport-Security: max-age=2592000
X-Content-Type-Options: nosniff