Extract basic in-flight counting navigator

lib/Navigator.js

@@ -0,0 +1,98 @@
+/**
+ * Copyright 2017 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.
+ */
+
+class Navigator {
+    /**
+     * @param {!Connection} client
+     * @param {!Object=} options
+     */
+    constructor(client, options) {
+        this._client = client;
+        client.on('Network.requestWillBeSent', event => this._onRequestWillBeSent(event));
+        client.on('Network.loadingFinished', event => this._onLoadingFinished(event));
+        client.on('Network.loadingFailed', event => this._onLoadingFailed(event));
+        this._minTime = options && options['minTime'] ? options['minTime'] : 0;
+        this._maxTime = options && options['maxTime'] ? options['maxTime'] : 30000;
+        this._inflightRequests = 0;
+    }
+
+    /**
+     * @param {string} url
+     * @param {string=} referrer
+     */
+    async navigate(url, referrer) {
+        this._navigationStartTime = Date.now();
+        this._watchdogTimer = setTimeout(this._completeNavigation.bind(this, true), this._maxTime);
+        this._minimumTimer = setTimeout(this._completeNavigation.bind(this, false), this._minTime);
+        let onload = new Promise(fulfill => this._client.once('Page.loadEventFired', fulfill));
+        let networkIdle = new Promise(fulfill => this._navigationLoadCallback = fulfill);
+        var interstitialPromise = new Promise(fulfill => this._client.once('Security.certificateError', fulfill)).then(() => false);
+
+        this._inflightRequests = 0;
+        // Await for the command to throw exception in case of illegal arguments.
+        try {
+            await this._client.send('Page.navigate', {url, referrer});
+        } catch (e) {
+            return false;
+        }
+        return await Promise.race([Promise.all([onload, networkIdle]).then(() => true), interstitialPromise]);
+    }
+
+    /**
+     * @param {!Object} event
+     */
+    _onRequestWillBeSent(event) {
+        if (!event.redirectResponse)
+          ++this._inflightRequests;
+    }
+
+    /**
+     * @param {!Object} event
+     */
+    _onLoadingFinished(event) {
+        this._onLoadingCompleted(event);
+    }
+
+    /**
+     * @param {!Object} event
+     */
+    _onLoadingFailed(event) {
+        this._onLoadingCompleted(event);
+    }
+
+    _onLoadingCompleted(event) {
+        --this._inflightRequests;
+        if (Date.now() - this._navigationStartTime < this._minTime)
+            return;
+        this._completeNavigation(false);
+    }
+
+    /**
+     * @param {boolean} force
+     */
+    _completeNavigation(force) {
+        if (!this._navigationLoadCallback)
+            return;
+        if (this._inflightRequests < 2 || force) {
+            clearTimeout(this._minimumTimer);
+            clearTimeout(this._watchdogTimer);
+            this._navigationLoadCallback();
+            this._navigationLoadCallback = null;
+        }
+    }
+}
+
+module.exports = Navigator;

lib/Page.js

@@ -18,6 +18,7 @@ var fs = require('fs');
 var EventEmitter = require('events');
 var mime = require('mime');
 var Request = require('./Request');
+var Navigator = require('./Navigator');
 var Dialog = require('./Dialog');
 var FrameManager = require('./FrameManager');
 
@@ -66,6 +67,7 @@ class Page extends EventEmitter {
 
         client.on('Network.responseReceived', event => this.emit(Page.Events.ResponseReceived, event.response));
         client.on('Network.loadingFailed', event => this.emit(Page.Events.ResourceLoadingFailed, event));
+
         client.on('Network.requestIntercepted', event => this._onRequestIntercepted(event));
         client.on('Runtime.consoleAPICalled', event => this._onConsoleAPI(event));
         client.on('Page.javascriptDialogOpening', event => this._onDialog(event));
@@ -260,19 +262,11 @@ class Page extends EventEmitter {
 
     /**
      * @param {string} html
+     * @param {!Object=} options
      * @return {!Promise<boolean>}
      */
-    async navigate(url) {
-        var loadPromise = new Promise(fulfill => this._client.once('Page.loadEventFired', fulfill)).then(() => true);
-        var interstitialPromise = new Promise(fulfill => this._client.once('Security.certificateError', fulfill)).then(() => false);
-        var referrer = this._extraHeaders.referer;
-        // Await for the command to throw exception in case of illegal arguments.
-        try {
-            await this._client.send('Page.navigate', {url, referrer});
-        } catch (e) {
-            return false;
-        }
-        return await Promise.race([loadPromise, interstitialPromise]);
+    navigate(url, options) {
+        return new Navigator(this._client, options).navigate(url, this._extraHeaders.referer);
     }
 
     /**