redirect.js

/*
 * Copyright (C) 2012 - 2014  Bo Zhu  http://zhuzhu.org
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

/*jslint browser: true */
/*global chrome: false, unblock_youku: false, btoa: false */
/*global ga_report_error: false, string_starts_with: false */
"use strict";


function http_redirector(details) {
    console.log('original url: ' + details.url);
    if (details.url.slice(-15) === 'crossdomain.xml') {
        console.log('directly pass');
        return {};
    }
    var redirect_url = null;

    // special treatment for play.baidu
    if (details.url.slice(0, 41) === 'http://play.baidu.com/data/music/songlink') {
        redirect_url = 'http://play.baidu.com/data/cloud/songlink' + details.url.slice(41);
        console.log('redirect url: ' + redirect_url);
        return {redirectUrl: redirect_url};
    }

    // if (details.url.slice(0, 18) === 'http://v.youku.com') {
    //     // remove random number to improve cache hitrate
    //     details.url = details.url.replace(/&ran=[0-9]*|ran=[0-9]*&/gi, '');
    // } else if (details.url.slice(0, 23) === 'http://hot.vrs.sohu.com') {
    //     details.url = details.url.replace(/&t=0\.[0-9]*|t=0\.[0-9]*&/gi, '');
    // } else if (details.url.slice(0, 23) === 'http://hot.vrs.letv.com') {
    //     details.url = details.url.replace(/&tn=0\.[0-9]*|tn=0\.[0-9]*&/gi, '');
    // }

    var backend_server;
    if (typeof localStorage.custom_server === 'undefined') {
        backend_server = unblock_youku.actual_server;
    } else {
        backend_server = localStorage.custom_server;
    }

    //var redirect_url = 'http://127.0.0.1.xip.io:8080/?url=' + urlsafe_b64encode(details.url);
    if (string_starts_with(details.url, 'http://')) {
        redirect_url = 'http://' + backend_server + '/http/' + details.url.substring('http://'.length);
    } else if (string_starts_with(details.url, 'https://')) {
        redirect_url = 'http://' + backend_server + '/https/' + details.url.substring('https://'.length);
    }
    console.log('redirect url: ' + redirect_url);

    if (redirect_url !== null) {
        return {redirectUrl: redirect_url};
    }
    return {};
}


function check_redirect_server(server_addr, success_callback, failure_callback) {
    console.log('to test the redirection server: ' + server_addr);
    var xhr = new XMLHttpRequest();

    var xhr_timer = setTimeout(function() {
        xhr.abort();
        console.warn(server_addr + ' TIMEOUT!');
        failure_callback('Timeout');
    }, 10000);  // 10s

    xhr.open('GET', 'http://' + server_addr.match(/^(.[^\/]+)/)[1] + '/status', true);
    xhr.timeout = 12000; // 12s
    xhr.onreadystatechange = function() {
        if (xhr.readyState === 4) {
            if ((xhr.status === 200 || xhr.status === 304) 
                    && xhr.responseText.indexOf('OK') !== -1) {
                clearTimeout(xhr_timer);
                success_callback();
            } else {
                clearTimeout(xhr_timer);
                failure_callback('Wrong Status: [' + xhr.status + '] ' + xhr.responseText);
            }
        }
    };
    xhr.onerror = function(err) {
        console.warn(server_addr + ' ERROR!');
        clearTimeout(xhr_timer);
        failure_callback(JSON.stringify(err));
    };
    xhr.send();
}


function setup_redirect() {
    if (!chrome.webRequest.onBeforeRequest.hasListener(http_redirector)) {
        chrome.webRequest.onBeforeRequest.addListener(
            http_redirector,
            {
                urls: unblock_youku.redirect_url_list
            },
            ["blocking"]
        );
        console.log('http_redirector is set');
    } else {
        var err_msg = 'http_redirector is already there!';
        console.error(err_msg);
        ga_report_error('Unexpected Error', err_msg);
    }

    unblock_youku.actual_server = unblock_youku.default_server;
    check_redirect_server(unblock_youku.actual_server, function() {
        console.log('default_server seems to be working fine: ' + unblock_youku.actual_server);
    }, function(err_msg) {
        unblock_youku.actual_server = unblock_youku.backup_server;
        console.warn('default_server error: ' + err_msg);
        console.warn('changed to backup_server: ' + unblock_youku.actual_server);
        ga_report_error('Redirect Server Error', unblock_youku.default_server + ': ' + err_msg);
    });
}


function clear_redirect() {
    if (chrome.webRequest.onBeforeRequest.hasListener(http_redirector)) {
        chrome.webRequest.onBeforeRequest.removeListener(http_redirector);
        console.log('http_redirector is removed');
    } else {
        var err_msg = 'http_redirector is not there!';
        console.error(err_msg);
        ga_report_error('Unexpected Error', err_msg);
    }
}



// // extra sites to redirect
// function extra_http_redirector(details) {
//     if (details.url === 'http://netcncoversea.inter.iqiyi.com/crossdomain.xml') {
//         var redirect_url = 'http://pac.uku.im/crossdomain.xml';
//         console.log('redirect url: ' + redirect_url);
//         return {redirectUrl: redirect_url};
//     }
// }

// function setup_extra_redirector() {
//     if (!chrome.webRequest.onBeforeRequest.hasListener(extra_http_redirector)) {
//         chrome.webRequest.onBeforeRequest.addListener(
//             extra_http_redirector,
//             {
//                 urls: ['http://netcncoversea.inter.iqiyi.com/crossdomain.xml']
//             },
//             ["blocking"]
//         );
//         console.log('extra_http_redirector is set');
//     } else {
//         var err_msg = 'extra_http_redirector is already there!';
//         console.error(err_msg);
//         ga_report_error('Unexpected Error', err_msg);
//     }
// }