Script can't make POST request

Question

I have the following script:

from twisted.internet import reactor
import time,hashlib,urllib2,json,treq
from urllib import urlencode

#This is used to print out the Password that is found. This is called at the
# end of each loop. And checks if response code == 200.
def done(response):
    if response.code == 200:
        sys.stdout.write( Password + "FOUND" )
#The Password is basically a 4 digit number, the line under starts with number 0.
PasswordStart = 0
#This is an array to make sure that the script does not do double requests to the host.
executed = []
#Loop which runs the URL request 10000 times
while PasswordStart<9999:
    #Checks if PasswordStart is in array
    if PasswordStart not in executed and PasswordStart<9999:
        #Since PasswordStart is not in array, it will add it to the array
        #and then run the rest of the code.
        executed.append(PasswordStart)
        #Makes a variable of the time/date, used later in headers
        Timing = time.strftime("%Y-%m-%dT%H:%M:%S.00+00:00")
        #Just four variables for registration date, which is used later in
        # the datas_p variable
        YearRegD = time.strftime("%Y")
        DateRegD = time.strftime("-%m-%d")
        YearRegD2 = str((int(YearRegD)-1))
        RegD = YearRegD2 + DateRegD
        #UserAgent for the request
        UserAgent = "Samsung Galaxy S8 - 7.0.0"
        #Username for datas_p data later
        UName = "JamesRicky"
        #Makes the PasswordStart into 4 digits: 0 becomes 0000, 40 becomes 0040.
        Password = str(PasswordStart).zfill(4)
        #These two hashes my string and makes a variable with the hash,
        # which is later used in the headers part of request
        HASH = hashlib.md5()
        HASH.update(time.strftime("%Y-%m-%dT%H:%M:%S.00+00:00")+UName+Password)

        #Now the fun part, defines url for the post request
        url = "http://example.com/user"
        #JSON data for the POST request
        datas_p = {'Username': UName, 'Password': Password, 'RegDate': RegD}
        #URLencodes JSON - Not sure if this is needed or not
        datas = urlencode(datas_p)

        #The headers for the POST request
        headers = ({
                'User-Agent': [UserAgent],
                'Date': [Timing],
                'Secret-Key': [HASH.hexdigest()],
                'Content-type': ['application/json'],
                'Accept-encoding': ['gzip'],
                'Accept': ['*/*'],

        })

        #Sends the treq.post request using the information from above (url, data, headers)
        d = treq.post(url, data=datas, headers=headers)
        #Adds call back in done def above.
        d.addCallback(done)
        #Adds up on the PasswordStart, so it tries another password for the
        next request in the loop.
        PasswordStart+=1

reactor.run()

When I run it, it runs through the loop, but makes 0 requests (no matter which host I have put). Which means there is something wrong with the treq.post request.

What am I doing wrong here?

EDIT: Here is the documentation for treq: https://treq.readthedocs.io/en/latest/ It is supposed to be a lot like requests and based on twisted.

EDIT 2: Here is an example code of how treq is supposed to make requests:

http://nullege.com/codes/show/src%40b%40t%40btcx-HEAD%40btcx%40btce.py/51/treq.post/python

I have had no luck in finding out what I did wrong reading the above code.

Answer 1

First of all, twisted is a server app, so logging is a must to know what's happening:

twisted.python.log.startLogging(sys.stdout)

Now, Password is not defined in the context that done() is executing in (or maybe it is but has an irrelevant value once the Deferred is executing). You need to pass the extra data to the callback explicitly as per How to pass extra arguments to callback register functions with twisted python api? :

def done(response,Password):
    if response.code == 200:
        sys.stdout.write( Password + "FOUND" )

<...>
d.addCallback(done,Password)

(Note that for variables, PEP8 recommends lowercase_with_underscores naming convention, CamelCase is used for type names. I only deviated from it to conform to your existing code.)

Finally, there's no reactor.stop(), so your code will run indefinitely. One way to stop is to use twisted.internet.task.react instead of reactor and defer.gatherResults as the main task that will call all the others, the completion of which will signal the reactor to stop, as per stop a twisted reactor after a gatherResults has finished:

def main():
    #checkPassword() returns a Deferred for trying the corresponding password
    calls = [checkPassword(password) for password in ('%04d'%i for i in range(10000))]
    d=defer.gatherResults(calls)
    return d

twisted.internet.task.react(main,[])

Answer 2

The problem is that you were not using the reactor properly. Note I don't actually know what this reactor does, but I believe it was essential for the application to function properly.

Judging from an example found online, you are not to import the reactor directly, but rather have twisted create and pass it to you via a method callback.

As an example (taken online and modified):

import json

from twisted.internet import defer, task
import treq

def response_recieved(response, password):
    response.json().addCallback(lambda payload: print(payload, password))

def main(reactor, *args):
    d = treq.post('http://httpbin.org/post',
                  json.dumps({"msg": "Hello!"}).encode('ascii'),
                  headers={b'Content-Type': [b'application/json']})
    d.addCallback(response_recieved, 42)
    return d

task.react(main, [])

The output I get after running this is:

{'url': 'http://httpbin.org/post', 'json': {'msg': 'Hello!'}, 'files': {}, 'headers': {'Connection': 'close', 'Content-Type': 'application/json', 'Content-Length': '17', 'Accept-Encoding': 'gzip', 'Host': 'httpbin.org'}, 'origin': '127.0.0.1', 'args': {}, 'form': {}, 'data': '{"msg": "Hello!"}'} 42

NOTE

With python 2, to run the above example, you also need to have the following import statement at the top of the file:

from __future__ import print_function