How to use cookies in Python Requests

Question

I am trying to login to a page and access another link in the page.

payload={'username'=<username>,'password'=<password>}
with session() as s:
    r = c.post(<URL>, data=payload)
    print r
    print r.content

This is giving me a "405 Not Allowed" error. I checked the post method details using chrome developer tools and could see an api (URL/api/auth). I posted to that URL with the payload and it was working and i was getting a response similar to what i could see in the developer.

Unfortunately when trying to 'get' another url after login, i am still getting the content from the login page. Why is the login not sticking? Should i use cookies? I am a newbie, so i don't really know how to work with cookies.

Solution 1

You can use a session object. It stores the cookies so you can make requests, and it handles the cookies for you

s = requests.Session() 
# all cookies received will be stored in the session object

s.post('http://www...',data=payload)
s.get('http://www...')

Docs: https://requests.readthedocs.io/en/master/user/advanced/#session-objects

You can also save the cookie data to an external file, and then reload them to keep session persistent without having to login every time you run the script:

How to save requests (python) cookies to a file?

Solution 2

From the documentation:

1. get cookie from response

    url = 'http://example.com/some/cookie/setting/url'
    r = requests.get(url)
    r.cookies
   

   {'example_cookie_name': 'example_cookie_value'}

2. give cookie back to server on subsequent request

    url = 'http://httpbin.org/cookies'
    cookies = {'cookies_are': 'working'}
    r = requests.get(url, cookies=cookies)`
   

Solution 3

Summary (@Freek Wiekmeijer, @gtalarico) other's answer:

Logic of Login

• Many resource(pages, api) need authentication, then can access, otherwise 405 Not Allowed
• Common authentication=grant access method are:
  • cookie
  • auth header
    • Basic xxx
    • Authorization xxx

How use cookie in requests to auth

1. first get/generate cookie
2. send cookie for following request

• manual set cookie in headers
• auto process cookie by requests's
  • session to auto manage cookies
  • response.cookies to manually set cookies

use requests's session auto manage cookies

curSession = requests.Session() 
# all cookies received will be stored in the session object

payload={'username': "yourName",'password': "yourPassword"}
curSession.post(firstUrl, data=payload)
# internally return your expected cookies, can use for following auth

# internally use previously generated cookies, can access the resources
curSession.get(secondUrl)

curSession.get(thirdUrl)

manually control requests's response.cookies

payload={'username': "yourName",'password': "yourPassword"}
resp1 = requests.post(firstUrl, data=payload)

# manually pass previously returned cookies into following request
resp2 = requests.get(secondUrl, cookies= resp1.cookies)

resp3 = requests.get(thirdUrl, cookies= resp2.cookies)

Comments

[user1474157]

Thanks. Actually, it seems there are no cookies that getting created. I checked the request headers and could not see any 'cookies'. Meanwhile there is one cookie created in response headers. How can i make my login stick if there is no cookie.

[Freek Wiekmeijer]

The normal flow for an authentication cookie is: (1) when you submit a login form, you receive a cookie in the response headers. (2) on subsequent page requests, you add the cookie to the request headers.

[Aurelius]

:O This is amazing! I wish I had known about this feature before. Is it storing the cookies on disk like a browser, or just holding them in memory?

[gtalarico]

It just keeps them in memory while the application is running. To save/load cookies from disk see this: stackoverflow.com/a/30441145/4411196

[yashas123]

I instead of saving them, made a global variable assigned it a session and made a function so it logins if the cookie is not there and/or returns the session

[Jitin]

how do you add multiple cookies ?

[Freek Wiekmeijer]

The kwarg “cookies” is a dict, you can add as many items as you want.

[Andrzej Martyna]

for me print(s.cookies) shows that cookies are in the session but are not always passed in subsequent requests (in fact the same code works against localhost but against a test server does not)