122 lines
4.3 KiB
JavaScript
122 lines
4.3 KiB
JavaScript
const querystring = require('querystring');
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const Cache = require('./cache');
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const utils = require('./utils');
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const vm = require('vm');
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// A shared cache to keep track of html5player js functions.
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exports.cache = new Cache();
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/**
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* Extract signature deciphering and n parameter transform functions from html5player file.
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*
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* @param {string} html5playerfile
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* @param {Object} options
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* @returns {Promise<Array.<string>>}
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*/
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exports.getFunctions = (html5playerfile, options) => exports.cache.getOrSet(html5playerfile, async() => {
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const body = await utils.exposedMiniget(html5playerfile, options).text();
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const functions = exports.extractFunctions(body);
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if (!functions || !functions.length) {
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throw Error('Could not extract functions');
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}
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exports.cache.set(html5playerfile, functions);
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return functions;
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});
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/**
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* Extracts the actions that should be taken to decipher a signature
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* and tranform the n parameter
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*
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* @param {string} body
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* @returns {Array.<string>}
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*/
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exports.extractFunctions = body => {
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const functions = [];
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const extractManipulations = caller => {
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const functionName = utils.between(caller, `a=a.split("");`, `.`);
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if (!functionName) return '';
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const functionStart = `var ${functionName}={`;
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const ndx = body.indexOf(functionStart);
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if (ndx < 0) return '';
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const subBody = body.slice(ndx + functionStart.length - 1);
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return `var ${functionName}=${utils.cutAfterJSON(subBody)}`;
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};
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const extractDecipher = () => {
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const functionName = utils.between(body, `a.set("alr","yes");c&&(c=`, `(decodeURIC`);
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if (functionName && functionName.length) {
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const functionStart = `${functionName}=function(a)`;
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const ndx = body.indexOf(functionStart);
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if (ndx >= 0) {
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const subBody = body.slice(ndx + functionStart.length);
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let functionBody = `var ${functionStart}${utils.cutAfterJSON(subBody)}`;
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functionBody = `${extractManipulations(functionBody)};${functionBody};${functionName}(sig);`;
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functions.push(functionBody);
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}
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}
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};
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const extractNCode = () => {
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const functionName = utils.between(body, `&&(b=a.get("n"))&&(b=`, `(b)`);
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if (functionName && functionName.length) {
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const functionStart = `${functionName}=function(a)`;
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const ndx = body.indexOf(functionStart);
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if (ndx >= 0) {
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const subBody = body.slice(ndx + functionStart.length);
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const functionBody = `var ${functionStart}${utils.cutAfterJSON(subBody)};${functionName}(ncode);`;
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functions.push(functionBody);
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}
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}
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};
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extractDecipher();
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extractNCode();
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return functions;
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};
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/**
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* Apply decipher and n-transform to individual format
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*
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* @param {Object} format
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* @param {vm.Script} decipherScript
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* @param {vm.Script} nTransformScript
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*/
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exports.setDownloadURL = (format, decipherScript, nTransformScript) => {
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const decipher = url => {
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const args = querystring.parse(url);
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if (!args.s || !decipherScript) return args.url;
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const components = new URL(decodeURIComponent(args.url));
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components.searchParams.set(args.sp ? args.sp : 'signature',
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decipherScript.runInNewContext({ sig: decodeURIComponent(args.s) }));
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return components.toString();
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};
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const ncode = url => {
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const components = new URL(decodeURIComponent(url));
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const n = components.searchParams.get('n');
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if (!n || !nTransformScript) return url;
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components.searchParams.set('n', nTransformScript.runInNewContext({ ncode: n }));
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return components.toString();
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};
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const cipher = !format.url;
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const url = format.url || format.signatureCipher || format.cipher;
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format.url = cipher ? ncode(decipher(url)) : ncode(url);
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delete format.signatureCipher;
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delete format.cipher;
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};
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/**
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* Applies decipher and n parameter transforms to all format URL's.
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*
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* @param {Array.<Object>} formats
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* @param {string} html5player
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* @param {Object} options
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*/
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exports.decipherFormats = async(formats, html5player, options) => {
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let decipheredFormats = {};
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let functions = await exports.getFunctions(html5player, options);
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const decipherScript = functions.length ? new vm.Script(functions[0]) : null;
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const nTransformScript = functions.length > 1 ? new vm.Script(functions[1]) : null;
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formats.forEach(format => {
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exports.setDownloadURL(format, decipherScript, nTransformScript);
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decipheredFormats[format.url] = format;
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});
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return decipheredFormats;
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};
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