const got = require("got"),
ua = require("random-useragent"),
sleep = require("./sleep.js");
class Decoder{
/**
* @static requestChallenge - Requests information about Kahoot! challenges.
*
* @param {String<Number>} pin The gameid of the challenge the client is trying to connect to
* @param {Client} client The client
* @returns {Promise<Object>} The challenge data
*/
static async requestChallenge(pin,client){
let tries = 0;
async function handleRequest(){
let options = {
headers: {
"User-Agent": ua.getRandom(),
"Origin": "kahoot.it",
"Referer": "https://kahoot.it/",
"Accept-Language": "en-US,en;q=0.8",
"Accept": "*/*"
},
host: "kahoot.it",
protocol: "https:",
path: `/rest/challenges/pin/${pin}`
};
const proxyOptions = client.defaults.proxy(options);
options = proxyOptions || options;
const request = got(options);
client.emit("_Request", request);
try{
const data = await request.json();
return {
data: Object.assign({
isChallenge: true,
twoFactorAuth: false,
kahootData: data.kahoot,
rawChallengeData: data.challenge
},data.challenge.game_options)
};
}catch(e){
if(tries < 2){
tries++;
await sleep(2);
return await handleRequest();
}
throw {
description: "Failed to get challenge data",
error: e
};
}
}
return await handleRequest();
}
/**
* @static requestToken - Requests the token for live games.
*
* @param {String<Number>} pin The gameid
* @param {Client} client The client
* @returns {Promise<object>} The game options
*/
static async requestToken(pin,client){
let tries = 0;
async function handleRequest(){
let options = {
headers: {
"User-Agent": ua.getRandom(),
"Origin": "kahoot.it",
"Referer": "https://kahoot.it/",
"Accept-Language": "en-US,en;q=0.8",
"Accept": "*/*"
},
host: "kahoot.it",
path: `/reserve/session/${pin}/?${Date.now()}`,
protocol: "https:"
};
const proxyOptions = client.defaults.proxy(options);
options = proxyOptions || options;
const request = got(options);
client.emit("_Request", request);
try{
const {headers,body} = await request,
data = JSON.parse(body);
if(!headers["x-kahoot-session-token"]){
throw {
description: "Missing header token (pin doesn't exist)"
};
}
return {
token: Buffer.from(headers["x-kahoot-session-token"],"base64").toString("utf8"),
data
};
}catch(e){
tries ++;
if(tries < 3){
await sleep(2);
return await handleRequest();
}
throw e.description ? e : {
description: "Request failed or timed out.",
error: e
};
}
}
return await handleRequest();
}
/**
* @static solveChallenge - Solves the challenge for the various Kahoot! tokens.
*
* @param {String} challenge The JS function to execute to get the challenge token.
* @returns {String} The decoded token
*/
static solveChallenge(challenge){
let solved = "";
challenge = challenge.replace(/(\u0009|\u2003)/mg, "");
challenge = challenge.replace(/this /mg, "this");
challenge = challenge.replace(/ *\. */mg, ".");
challenge = challenge.replace(/ *\( */mg, "(");
challenge = challenge.replace(/ *\) */mg, ")");
// Prevent any logging from the challenge, by default it logs some debug info
challenge = challenge.replace("console.", "");
// Make a few if-statements always return true as the functions are currently missing
challenge = challenge.replace("this.angular.isObject(offset)", "true");
challenge = challenge.replace("this.angular.isString(offset)", "true");
challenge = challenge.replace("this.angular.isDate(offset)", "true");
challenge = challenge.replace("this.angular.isArray(offset)", "true");
(() => {
const EVAL_ = `var _ = {
replace: function() {
var args = arguments;
var str = arguments[0];
return str.replace(args[1], args[2]);
}
};
var log = function(){};return `;
// Concat the method needed in order to solve the challenge, then eval the string
const solver = Function(EVAL_ + challenge);
// Execute the string, and get back the solved token
solved = solver().toString();
})();
return solved;
}
/**
* @static concatTokens - Combines the two tokens to get the final token
*
* @param {String} headerToken The base64 decoded header token
* @param {String} challengeToken The decoded challenge token
* @returns {String} The final token
*/
static concatTokens(headerToken, challengeToken) {
// Combine the session token and the challenge token together to get the string needed to connect to the websocket endpoint
for (var token = "", i = 0; i < headerToken.length; i++) {
let char = headerToken.charCodeAt(i);
let mod = challengeToken.charCodeAt(i % challengeToken.length);
let decodedChar = char ^ mod;
token += String.fromCharCode(decodedChar);
}
return token;
}
/**
* @static resolve - The main function for getting token info
*
* @param {String<Number>} pin The gameid
* @param {Client} client The client
* @returns {Promise<Object>} The game information.
*/
static resolve(pin,client){
if(isNaN(pin)){
return new Promise((res,reject)=>{
reject({
description: "Invalid/Missing PIN"
});
});
}
if(pin[0] === "0"){
// challenges
return this.requestChallenge(pin,client);
}
return this.requestToken(pin,client).then(data=>{
const token2 = this.solveChallenge(data.data.challenge);
const token = this.concatTokens(data.token,token2);
return {
token,
data: data.data
};
});
}
}
/**
* @fileinfo This module contains functions for fetching important tokens used for connection
*/
module.exports = Decoder;