Unable to let my script generate few values automatically to be used within payload

Question

I've created a script to get the html elements from a target page by sending two https requests subsequently. My script can does the thing flawlessly. However, I had to copy the four values from chrome dev tools to fill in the four keys within payload in order to send the final http requests to reach the target page. This is the starting link and following are the description as to how I could reach the target page.

1. Click on the Find Hotel button (no need to change dates if chek-out date is by default at least one day longer than check-in date).
2. Tick the box like the image below and press the Book Now button just above it. Now, it should lead you to the target page automatically.
3. Upon reaching the target page titled as Enter Guest Details, parse the html elements from there

I've tried with (working one):

import requests
from bs4 import BeautifulSoup

url = 'https://booking.discoverqatar.qa/SearchHandler.aspx?'
second_url = 'https://booking.discoverqatar.qa/PassengerDetails.aspx?'

params = {
    'Module':'H','txtCity':'','hdnCity':'2947','txtHotel':'','hdnHotel':'',
    'fromDate':'05/11/2019','toDate':'07/11/2019','selZone':'','minSelPrice':'',
    'maxSelPrice':'','roomConfiguration':'2|0|','noOfRooms':'1',
    'hotelStandardArray':'63,60,54,50,52,51','CallFrom':'','DllNationality':'-1',
    'HdnNoOfRooms':'-1','SourceXid':'MTEzNzg=','mdx':''
}

payload = {
    'CallFrom':'MToxNjozOCBQTXxCMkN8MToxNjozOCBQTQ==',
    'Btype':'MToxNjozOCBQTXxBfDE6MTY6MzggUE0=',
    'PaxConfig':'MToxNjozOCBQTXwyfDB8MnwwfHwxOjE2OjM4IFBN',
    'usid':'MToxNjozOCBQTXxoZW54dmkzcWVnc3J3cXpld2lsa2ZwMm18MToxNjozOCBQTQ=='  
}

with requests.Session() as s:
    r = s.get(url,params=params,headers={"User-agent":"Mozilla/5.0"})
    res = s.get(second_url,params=payload,headers={
        "User-agent":"Mozilla/5.0",
        "Referer":r.url
        })
    soup = BeautifulSoup(res.text,'lxml')
    print(soup)

In the above script I've copied and pasted the value of CallFrom,Btype,PaxConfig and usid from dev tools to use within payload.

How can I fill in the values automatically to be used within payload?

Answer 1

Params sent to the second request is Base64 encoded, after decode they are:

    'CallFrom':'1:16:38 PM|B2C|1:16:38 PM',
    'Btype':'1:16:38 PM|A|1:16:38 PM',
    'PaxConfig':'1:16:38 PM|2|0|2|0||1:16:38 PM',
    'usid':'1:16:38 PM|henxvi3qegsrwqzewilkfp2m|1:16:38 PM'  

At first glance, you already notice they are in patterns of:

$date|$param|$date

Where $date is current time in the format of utc_ts_now.strftime("%I:%M:%S %p").

For $param section of these four parameters, I guess it should be fixed for CallFrom and Btype, usid is the session key, you can find it easily in the previous response.

PaxConfig is guest counts, it's related to roomConfiguration you sent in the first request.

To automate the second request, you would generate the decoded value for each parameter first, then encode them with Base64.

Update:

#!/usr/bin/env python3.7
import base64
from datetime import datetime

import requests


def first_request(session, params):
    url = 'https://booking.discoverqatar.qa/SearchHandler.aspx'
    r = session.get(url, params=params)
    return r


def second_request(session, params):
    url = 'https://booking.discoverqatar.qa/PassengerDetails.aspx'
    r = session.get(url, params=params)
    return r


def main():
    params1 = {
        'Module':             'H',
        'txtCity':            '',
        'hdnCity':            '2947',
        'txtHotel':           '',
        'hdnHotel':           '',
        'fromDate':           '05/11/2019',
        'toDate':             '07/11/2019',
        'selZone':            '',
        'minSelPrice':        '',
        'maxSelPrice':        '',
        'roomConfiguration':  '2|0|',
        'noOfRooms':          '1',
        'hotelStandardArray': '63,60,54,50,52,51',
        'CallFrom':           '',
        'DllNationality':     '-1',
        'HdnNoOfRooms':       '-1',
        'SourceXid':          'MTEzNzg=',
        'mdx':                ''
    }
    session = requests.Session()
    _ = first_request(session, params1)
    asp_session = session.cookies.get("ASP.NET_SessionId")

    params2 = {
        # Could related to options "Available" / "On Request"
        "Btype":     "A",

        # Try out other guest counts to make sure
        "PaxConfig": params1["roomConfiguration"] * 2,

        "CallFrom": "B2C",
        "usid":     asp_session
    }
    date = datetime.utcnow().strftime("%I:%M:%S %p")
    for k, v in params2.items():
        v = "|".join([date, v, date])
        v = base64.b64encode(bytes(v, "utf-8")).decode("utf-8")
        params2[k] = v
    r = second_request(session, params2)
    print(r.text)


if __name__ == '__main__':
    main()