runet-censorship-bypass/extensions/chromium/minimalistic-pac-setter/extension/1-sync-pac-script-with-pac-provider.js

'use strict';

/*
  Task 1. Gets IPs for proxies of antizapret/anticenz via dns over https.
          These IPs are used in block-informer to inform user when proxy is ON.
  Task 2. Downloads PAC proxy script from antizapret/anticenz/my Google Drive and sets it in Chromium settings.
  Task 3. Schedules tasks 1 & 2 for every 4 hours.
*/

/*
  In background scripts use window.antiCensorRu public variables.
  In pages window.antiCensorRu is not accessible,
    use chrome.runtime.getBackgroundPage(..),
    extension.getBackgroundPage is deprecated
*/
{ // Private namespace starts.

  window.antiCensorRu = {

    version: chrome.runtime.getManifest().version,

    pacProviders: {
      Антизапрет: {
        pacUrl: 'https://antizapret.prostovpn.org/proxy.pac',
        proxyHosts: ['proxy.antizapret.prostovpn.org'],
        proxyIps: {
          '195.123.209.38': 'proxy.antizapret.prostovpn.org',
          '2a02:27ac::10':  'proxy.antizapret.prostovpn.org'
        }
      },
      Антиценз: {
        pacUrl: 'https://config.anticenz.org/proxy.pac',
        proxyHosts: ['gw2.anticenz.org'],
        proxyIps: {
          '5.196.220.114': 'gw2.anticenz.org'
        }
      },
      Оба_и_на_свитчах: {
        //pacUrl: 'https://drive.google.com/uc?export=download&id=0B-ZCVSvuNWf0akpCOURNS2VCTmc', // 0.14
        pacUrl: 'https://drive.google.com/uc?export=download&id=0B-ZCVSvuNWf0bzNUR2F4RF8wOU0',   // 0.15
        proxyHosts: ['proxy.antizapret.prostovpn.org', 'gw2.anticenz.org'],
        proxyIps: {
          '195.123.209.38': 'proxy.antizapret.prostovpn.org',
          '2a02:27ac::10':  'proxy.antizapret.prostovpn.org',
          '5.196.220.114':  'gw2.anticenz.org'
        }
      }
    },

    _currentPacProviderKey: 'Оба_и_на_свитчах',

    get currentPacProviderKey() { return this._currentPacProviderKey },
    set currentPacProviderKey(newKey) {

      if (newKey && !this.pacProviders[newKey])
        throw new IllegalArgumentException('No provider for key:' + newKey);
      this._currentPacProviderKey = newKey;
    },

    get pacProvider() { return this.pacProviders[this.currentPacProviderKey] },

    /*
      Is it the first time extension installed? Do something, e.g. initiate PAC sync.
    */
    ifFirstInstall: false,
    lastPacUpdateStamp: 0,

    _periodicUpdateAlarmReason: 'Периодичное обновление PAC-скрипта Антизапрет',

    pushToStorage(cb) {

      console.log('Pushing to storage...');

      // Copy only settable properties (except functions).
      const onlySettable = {};
      for(const key of Object.keys(this)) {
        if (Object.getOwnPropertyDescriptor(this, key).writable && typeof(this[key]) !== 'function') {
          onlySettable[key] = this[key];
        }
      }

      return chrome.storage.local.clear(
        () => chrome.storage.local.set(
          onlySettable,
          chromified(cb, onlySettable)
        )
      );

    },

    pullFromStorage(cb) {

      chrome.storage.local.get(null, (storage) => {

        const err = checkChromeError();
        if (!err) {
          console.log('Pulled from storage:', storage);
          for(const key of Object.keys(storage)) {
            this[key] = storage[key];
          }
        }

        console.log('Synced with storage, any callback?', !!cb);
        return cb && cb(err, storage);

      });
    },

    syncWithPacProvider(cb) {

      cb = asyncLogGroup('Syncing with PAC provider...', cb);
      if (!this.pacProvider) {
        return cb({clarification:{message:'Сперва выберите PAC-провайдера.'}});
      }

      const pacSetPromise = new Promise(
        (resolve, reject) => setPacScriptFromProvider(
          this.pacProvider,
          (err, res) => {

            if (!err) {
              this.lastPacUpdateStamp = Date.now();
              this.ifFirstInstall = false;
              this.setAlarms();
            }

            return resolve([err, res]);

          }
        )
      );

      const ipsPromise = new Promise(
        (resolve, reject) => updatePacProxyIps(
          this.pacProvider,
          (ipsError) => {

            if (ipsError && ipsError.clarification) {
              ipsError.clarification.ifNotCritical = true;
            }
            return resolve([ipsError]);

          }
        )
      );

      Promise.all([pacSetPromise, ipsPromise]).then(
        ([[pacErr, pacRes], [ipsErr]]) => {

          if (pacErr && ipsErr) {
            return cb(pacErr, pacRes);
          }
          return cb(pacErr || ipsErr);
          this.pushToStorage(
            (pushErr) => cb(pacErr || ipsErr || pushErr, pacRes)
          );

        }
      );

    },

    _pacUpdatePeriodInMinutes: 4*60,

    setAlarms() {

      let nextUpdateMoment = this.lastPacUpdateStamp + this._pacUpdatePeriodInMinutes*60*1000;
      const now = Date.now();
      if (nextUpdateMoment < now) {
        nextUpdateMoment = now;
      }

      console.log( 'Next PAC update is scheduled on', new Date(nextUpdateMoment).toLocaleString('ru-RU') );

      chrome.alarms.create(
        this._periodicUpdateAlarmReason,
        {
          when: nextUpdateMoment,
          periodInMinutes: this._pacUpdatePeriodInMinutes
        }
      );

      return nextUpdateMoment === now; // ifAlarmTriggered. May be changed in the future.

    },

    installPac(key, cb) {

      console.log('Installing PAC');
      if(typeof(key) === 'function') {
        cb = key;
        key = undefined;
      }

      if(key) {
        this.currentPacProviderKey = key;
      }

      return this.syncWithPacProvider(cb);

    },

    clearPac(cb) {

      cb = asyncLogGroup('Cearing alarms and PAC...', cb);
      chrome.alarms.clearAll(
        () => chrome.proxy.settings.clear(
          {},
          () => {

            const err = checkChromeError();
            if (err) {
              return cb(err);
            }
            this.currentPacProviderKey = undefined;
            return this.pushToStorage(cb);

          }
        )
      );
    }

  };

  // ON EACH LAUNCH, STARTUP, RELOAD, UPDATE, ENABLE
  chrome.storage.local.get(null, (oldStorage) => {

    console.log('Init on storage:', oldStorage);
    antiCensorRu.ifFirstInstall = Object.keys(oldStorage).length === 0;

    if (!antiCensorRu.ifFirstInstall) {
      // LAUNCH, RELOAD, UPDATE
      antiCensorRu._currentPacProviderKey = oldStorage._currentPacProviderKey;
      antiCensorRu.lastPacUpdateStamp = oldStorage.lastPacUpdateStamp || antiCensorRu.lastPacUpdateStamp;
      console.log( 'Last PAC update was on', new Date(antiCensorRu.lastPacUpdateStamp).toLocaleString('ru-RU') );
    }

    chrome.alarms.onAlarm.addListener(
      (alarm) => {

        if (alarm.name === antiCensorRu._periodicUpdateAlarmReason) {
          console.log('Periodic PAC update triggered:', new Date().toLocaleString('ru-RU'));
          antiCensorRu.syncWithPacProvider(/* Swallows errors. */);
        }

      }
    );
    console.log('Alarm listener installed. We won\'t miss any PAC update.');

    window.addEventListener('online',  () => {

      console.log('We are online, checking periodic updates...');
      antiCensorRu.setAlarms();

    });

    if (antiCensorRu.ifFirstInstall) {
      // INSTALL
      console.log('Installing...');
      return chrome.runtime.openOptionsPage();
    }

    if (!antiCensorRu.pacProvider) {
      return console.log('No PAC provider set. Do nothing.');
      /*
        In case of UPDATE:
          1. new providers will still be shown.
          2. new version won't be pushed to storage
      */
    }

    /*
      1. There is no way to check that chrome.runtime.onInstalled wasn't fired except timeout.
         Otherwise we could put storage migration code only there.
      2. We have to check storage for migration before using it.
         Better on each launch then on each pull.
    */

    const ifAlarmTriggered = antiCensorRu.setAlarms();

    if (antiCensorRu.version === oldStorage.version) {
      // LAUNCH, RELOAD, ENABLE
      antiCensorRu.pacProviders = oldStorage.pacProviders;
      return console.log('Extension launched, reloaded or enabled.');
    }

    // UPDATE & MIGRATION
    console.log('Extension updated.');
    if (!ifAlarmTriggered) {
      antiCensorRu.pushToStorage(/* Swallows errors. */);
    }

    /*
      History of Changes to Storage (Migration Guide)
      -----------------------------------------------
      Version 0.0.0.10
        * Added this.version
        * PacProvider.proxyIps changed from {ip -> Boolean} to {ip -> hostname}
      Version 0.0.0.8-9
        * Changed storage.ifNotInstalled to storage.ifFirstInstall
        * Added storage.lastPacUpdateStamp
    **/
  });

  function asyncLogGroup(...args) {

    const cb = args.pop() || (() => {});
    console.group.apply(console, args);
    return function(...cbArgs) {

      console.groupEnd();
      console.log('Group finished.');
      return cb.apply(this, cbArgs);

    }
  }

  function checkChromeError(betterStack) {

    // Chrome API calls your cb in a context different from the point of API method invokation.
    const err = chrome.runtime.lastError || chrome.extension.lastError || null;
    if (err) {
      const args = ['API returned error:', err];
      if (betterStack) {
        args.push('\n' + betterStack);
      }
      console.warn.apply(console, args);
    }
    return err;

  }

  function chromified(cb, ...replaceArgs) {

    const stack = (new Error()).stack;
    // Take error first callback and covert it to chrome api callback.
    return function(...args) {

      if (replaceArgs.length) {
        args = replaceArgs;
      }
      const err = checkChromeError(stack);
      return cb && cb.call(this, err, ...args);

    };

  }

  function httpGet(url, cb) {

    const start = Date.now();
    return fetch(url).then(
      (res) => {

        const textCb =
          (err) => cb && res.text()
            .then( (text) => cb(err, text), cb );
        const status = res.status;
        if ( !( status >= 200 && status < 300 || status === 304 ) ) {
          res.clarification = {message: 'Получен ответ с неудачным HTTP-кодом ' + status + '.'};
          return textCb(res);
        }
        console.log('GETed with success:', url, Date.now() - start);
        return textCb();

      },
      (err) => {

        err.clarification = {message: 'Что-то не так с сетью, проверьте соединение.'};
        return cb && cb(err);

      }
    );
  }

  function getOneDnsRecord(args, cb) {

    // args: { host:..., type: 'AAAA', filter: ['AAAA'] }
    if (!(args.host && args.type && cb)) {
      throw new Error('Wrong args:' + host + ',' + type);
    }

    const type2str = {
      // https://en.wikipedia.org/wiki/List_of_DNS_record_types
      // A, AAAA may be localized (github, e.g.), but you may use ANY
      1:  'A',      // IPv4
      28: 'AAAA',   // IPv6
      2:  'NS',
      5:  'CNAME',  // Synonyms, returned by server together with A/AAAA.
      255: 'ANY'    // Deprecated on some servers, not recommended
    };

    httpGet(
      'https://dns.google.com/resolve?type=' + args.type + '&name=' + args.host,
      (err, res) => {
        if (res) {
          try {
            res = JSON.parse(res);
            console.log('Json parsed.');
            if (err || res.Status) {
              const msg = ['Answer', 'Comment', 'Status']
                .filter( (prop) => res[ prop ] )
                .map( (prop) => prop + ': ' + JSON.stringify( res[ prop ] ) )
                .join(', \n');
              err.clarification.message += ' Сервер (json): ' + msg;
              err.data = err.data || res;
            }
            else {
              res = res.Answer || [];
              for (const record of res) {
                record.type = type2str[ record.type ];
              }
              if ( args.filter ) {
                res = res.filter( (record) => args.filter.indexOf( record.type ) > -1 );
              }
            }
          }
          catch(e) {
            err = e || err || {clarification:{message:''}};
            err.clarification = err.clarification || { message: '' };
            err.clarification.message += ' Сервер (текст): '+ res;
            err.clarification.message.trim();
            err.data = err.data || res;
          }
        }
        return cb( err, res );
      }
    );
  };

  function getDnsRecords(args, cb) {

    /*
      Example of input:
        {
          // Required
            host: 'proxy.navalny.cia.gov',
          // Optional
            types: {
              string: ['A', 'AAAA'], // <- Default. Makes one request per each type.
              filter: ['A', 'AAAA'], // <- Default. E.g., you want to get rid of CNAME type from response.
            }
        }
      Exmple of answer from google:
        "Answer":
        [
          {
            "name": "apple.com.",   // Always matches name in the Question section
            "type": 1,              // A - Standard DNS RR type
            "TTL": 3599,            // Record's time-to-live in seconds
            "data": "17.178.96.59"  // Data for A - IP address as text
          },
        ...
      Exmple of output:
        The same as google, but types _may be_ canonical strings ('AAAA', 'A')
    **/

    if ( !args.host.length ) {
      throw new Error('args.host is required: ' + args.host);
    }
    args.types = Object.assign({
      string: ['A', 'AAAA'],
      filter: ['A', 'AAAA']
    }, args.types);

    const promises = args.types.string.map(
      (type) => new Promise( (resolve, reject) =>
        getOneDnsRecord({ host: args.host, type: type, filter: args.types.filter }, (err, res) => err ? reject(err) : resolve(res) )
      )
    );
    Promise.all(promises).then( (answers) => cb( null, [].concat.apply([], answers) ), cb );
  }

  const getIpDnsRecords = (host, cb) => getDnsRecords({ host: host }, cb);

  function updatePacProxyIps(provider, cb) {

    cb = asyncLogGroup('Getting IP for '+ provider.proxyHosts.join(', ') +'...', cb);
    let failure = {
      clarification: {message:'Не удалось получить один или несколько IP адресов для прокси-серверов. Иконка для уведомления об обходе блокировок может не отображаться.'},
      errors: {}
    };
    let i = 0;
    provider.proxyHosts.map(
      (proxyHost) => getIpDnsRecords(
        proxyHost,
        (err, records) => {

          if (!err) {
            provider.proxyIps = provider.proxyIps || {};
            records.forEach( (ans) => provider.proxyIps[ ans.data ] = proxyHost );
          }
          else {
            failure.errors[proxyHost] = err;
          }

          if ( ++i === provider.proxyHosts.length ) {
            failure = Object.keys(failure.errors).length ? failure : null;
            return cb(failure, provider.proxyIps);
          }
        }
      )
    );
  }

  function setPacScriptFromProvider(provider, cb) {

    cb = asyncLogGroup('Getting pac script from provider...', provider.pacUrl, cb);

    httpGet(
      provider.pacUrl,
      (err, pacData) => {

        if (err) {
          err.clarification = {
            message: 'Не удалось скачать PAC-скрипт с адреса: ' + provider.pacUrl + '.',
            prev: err.clarification
          };
          return cb(err);
        }

        const config = {
          mode: 'pac_script',
          pacScript: {
            mandatory: false,
            data: pacData
          }
        };
        console.log('Setting chrome proxy settings...');
        chrome.proxy.settings.set( {value: config}, chromified(cb) );

      }
    );
  }

}

window.addEventListener('error', (err) => {

  console.error('Global error');

});

window.addEventListener('unhandledrejection', (event) => {

  console.warn('Unhandled rejection. Throwing error.');
  event.preventDefault();
  throw event.reason;

});