How to use python urllib2 to send json data for login

Question

I want to use python urllib2 to simulate a login action, I use Fiddler to catch the packets and got that the login action is just an ajax request and the username and password is sent as json data, but I have no idea how to use urllib2 to send json data, help...

Answer 1

For Python 3.x

Note the following

• In Python 3.x the urllib and urllib2 modules have been combined. The module is named urllib. So, remember that urllib in Python 2.x and urllib in Python 3.x are DIFFERENT modules.

• The POST data for urllib.request.Request in Python 3 does NOT accept a string (str) -- you have to pass a bytes object (or an iterable of bytes)

Example

pass json data with POST in Python 3.x

import urllib.request
import json

json_dict = { 'name': 'some name', 'value': 'some value' }

# convert json_dict to JSON
json_data = json.dumps(json_dict)

# convert str to bytes (ensure encoding is OK)
post_data = json_data.encode('utf-8')

# we should also say the JSON content type header
headers = {}
headers['Content-Type'] = 'application/json'

# now do the request for a url
req = urllib.request.Request(url, post_data, headers)

# send the request
res = urllib.request.urlopen(req)

# res is a file-like object
# ...

Finally note that you can ONLY send a POST request if you have SOME data to send.

If you want to do an HTTP POST without sending any data, you should send an empty dict as data.

data_dict = {}
post_data = json.dumps(data_dict).encode()

req = urllib.request.Request(url, post_data)
res = urllib.request.urlopen(req)