# all files / lighthouse-core/driver/ index.js

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79.17% Branches 19/24
100% Functions 10/10
96.59% Lines 85/88

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     /**
     * @license
     * Copyright 2016 Google Inc. All rights reserved.
     *
     * Licensed under the Apache License, Version 2.0 (the "License");
     * you may not use this file except in compliance with the License.
     * You may obtain a copy of the License at
     *
     *     http://www.apache.org/licenses/LICENSE-2.0
     *
     * Unless required by applicable law or agreed to in writing, software
     * distributed under the License is distributed on an "AS IS" BASIS,
     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     * See the License for the specific language governing permissions and
     * limitations under the License.
     */
    'use strict';

    class Driver {

      static loadPage(driver, options) {
        // Since a Page.reload command does not let a service worker take over, we
        // navigate away and then come back to reload. We do not `waitForLoad` on
        // about:blank since a page load event is never fired on it.
        return driver.gotoURL('about:blank')
          // Wait a bit for about:blank to "take hold" before switching back to the page.
          .then(_ => new Promise((resolve, reject) => setTimeout(resolve, 300)))
          .then(_ => driver.gotoURL(options.url, {
            waitForLoad: true, disableJavaScript: !!options.disableJavaScript
          }));
      }

      static setupDriver(driver, gatherers, options) {
        return new Promise((resolve, reject) => {
          // Enable emulation.
          if (options.flags.mobile) {
            return resolve(driver.beginEmulation());
          }

          // noop if no mobile emulation
          resolve();
        }).then(_ => {
          return driver.cleanAndDisableBrowserCaches();
        }).then(_ => {
          // Force SWs to update on load.
          return driver.forceUpdateServiceWorkers();
        });
      }

      static setup(options) {
        const driver = options.driver;
        const config = options.config;
        const gatherers = config.gatherers;
        let pass = Promise.resolve();

        if (config.trace) {
          pass = pass.then(_ => driver.beginTrace());
        }

        if (config.network) {
          pass = pass.then(_ => driver.beginNetworkCollect());
        }

        return gatherers.reduce((chain, gatherer) => {
          return chain.then(_ => gatherer.setup(options));
        }, pass);
      }

      static beforePass(options) {
        const config = options.config;
        const gatherers = config.gatherers;

        return gatherers.reduce((chain, gatherer) => {
          return chain.then(_ => {
            return gatherer.beforePass(options);
          });
        }, Promise.resolve());
      }

      static pass(options) {
        const driver = options.driver;
        const config = options.config;
        const gatherers = config.gatherers;
        let pass = Promise.resolve();

        Eif (config.loadPage) {
          pass = pass.then(_ => this.loadPage(driver, options));
        }

        return gatherers.reduce((chain, gatherer) => {
          return chain.then(_ => gatherer.pass(options));
        }, pass);
      }

      static afterPass(options) {
        const driver = options.driver;
        const config = options.config;
        const gatherers = config.gatherers;
        const loadData = {};
        let pass = Promise.resolve();

        if (config.trace) {
          pass = pass.then(_ => driver.endTrace().then(traceContents => {
            loadData.traceContents = traceContents;
          }));
        }

        if (config.network) {
          pass = pass.then(_ => driver.endNetworkCollect().then(networkRecords => {
            loadData.networkRecords = networkRecords;
          }));
        }

        return gatherers
            .reduce((chain, gatherer) => {
              return chain.then(_ => gatherer.afterPass(options, loadData));
            }, pass)
            .then(_ => loadData);
      }

      static tearDown(options) {
        const config = options.config;
        const gatherers = config.gatherers;
        return gatherers.reduce((chain, gatherer) => {
          return chain.then(_ => gatherer.tearDown(options));
        }, Promise.resolve());
      }

      static run(passes, options) {
        const driver = options.driver;
        const tracingData = {};

        if (typeof options.url !== 'string' || options.url.length === 0) {
          return Promise.reject(new Error('You must provide a url to the driver'));
        }

        Iif (typeof options.flags === 'undefined') {
          options.flags = {};
        }

        // Default mobile emulation and page loading to true.
        // The extension will switch these off initially.
        Eif (typeof options.flags.mobile === 'undefined') {
          options.flags.mobile = true;
        }

        Eif (typeof options.flags.loadPage === 'undefined') {
          options.flags.loadPage = true;
        }

        passes = this.instantiateGatherers(passes);

        return driver.connect()
          .then(_ => this.setupDriver(driver, 1, options))

          // Run each pass
          .then(_ => {
            return passes.reduce((chain, config) => {
              const runOptions = Object.assign({}, options, {config});
              return chain
                  .then(_ => this.setup(runOptions))
                  .then(_ => this.beforePass(runOptions))
                  .then(_ => this.pass(runOptions))
                  .then(_ => this.afterPass(runOptions))
                  .then(loadData => {
                    Object.assign(tracingData, loadData);
                  })
                  .then(_ => this.tearDown(runOptions));
            }, Promise.resolve());
          })

          // Reload the page to remove any side-effects of Lighthouse (like disabling JavaScript).
          .then(_ => this.loadPage(driver, options))

           // Finish and teardown.
          .then(_ => driver.disconnect())
          .then(_ => {
            // Collate all the gatherer results.
            const artifacts = Object.assign({}, tracingData);
            passes.forEach(pass => {
              pass.gatherers.forEach(gatherer => {
                artifacts[gatherer.name] = gatherer.artifact;
              });
            });

            return artifacts;
          });
      }

      static getGathererClass(gatherer) {
        return require(`./gatherers/${gatherer}`);
      }

      static instantiateGatherers(passes) {
        return passes.map(pass => {
          pass.gatherers = pass.gatherers.map(gatherer => {
            // If this is already instantiated, don't do anything else.
            Eif (typeof gatherer !== 'string') {
              return gatherer;
            }

            const GathererClass = require(`./gatherers/${gatherer}`);
            return new GathererClass();
          });

          return pass;
        });
      }
    }

    module.exports = Driver;