| // Copyright 2006 The Closure Library Authors. 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. |
| |
| /** |
| * @fileoverview tmpnetwork.js contains some temporary networking functions |
| * for browserchannel which will be moved at a later date. |
| */ |
| |
| |
| /** |
| * Namespace for BrowserChannel |
| */ |
| goog.provide('goog.net.tmpnetwork'); |
| |
| goog.require('goog.Uri'); |
| goog.require('goog.net.ChannelDebug'); |
| |
| |
| /** |
| * Default timeout to allow for google.com pings. |
| * @type {number} |
| */ |
| goog.net.tmpnetwork.GOOGLECOM_TIMEOUT = 10000; |
| |
| |
| /** |
| * Pings the network to check if an error is a server error or user's network |
| * error. |
| * |
| * @param {Function} callback The function to call back with results. |
| * @param {goog.Uri?=} opt_imageUri The URI of an image to use for the network |
| * test. You *must* provide an image URI; the default behavior is provided |
| * for compatibility with existing code, but the search team does not want |
| * people using images served off of google.com for this purpose. The |
| * default will go away when all usages have been changed. |
| */ |
| goog.net.tmpnetwork.testGoogleCom = function(callback, opt_imageUri) { |
| // We need to add a 'rand' to make sure the response is not fulfilled |
| // by browser cache. |
| var uri = opt_imageUri; |
| if (!uri) { |
| uri = new goog.Uri('//www.google.com/images/cleardot.gif'); |
| uri.makeUnique(); |
| } |
| goog.net.tmpnetwork.testLoadImage(uri.toString(), |
| goog.net.tmpnetwork.GOOGLECOM_TIMEOUT, callback); |
| }; |
| |
| |
| /** |
| * Test loading the given image, retrying if necessary. |
| * @param {string} url URL to the iamge. |
| * @param {number} timeout Milliseconds before giving up. |
| * @param {Function} callback Function to call with results. |
| * @param {number} retries The number of times to retry. |
| * @param {number=} opt_pauseBetweenRetriesMS Optional number of milliseconds |
| * between retries - defaults to 0. |
| */ |
| goog.net.tmpnetwork.testLoadImageWithRetries = function(url, timeout, callback, |
| retries, opt_pauseBetweenRetriesMS) { |
| var channelDebug = new goog.net.ChannelDebug(); |
| channelDebug.debug('TestLoadImageWithRetries: ' + opt_pauseBetweenRetriesMS); |
| if (retries == 0) { |
| // no more retries, give up |
| callback(false); |
| return; |
| } |
| |
| var pauseBetweenRetries = opt_pauseBetweenRetriesMS || 0; |
| retries--; |
| goog.net.tmpnetwork.testLoadImage(url, timeout, function(succeeded) { |
| if (succeeded) { |
| callback(true); |
| } else { |
| // try again |
| goog.global.setTimeout(function() { |
| goog.net.tmpnetwork.testLoadImageWithRetries(url, timeout, callback, |
| retries, pauseBetweenRetries); |
| }, pauseBetweenRetries); |
| } |
| }); |
| }; |
| |
| |
| /** |
| * Test loading the given image. |
| * @param {string} url URL to the iamge. |
| * @param {number} timeout Milliseconds before giving up. |
| * @param {Function} callback Function to call with results. |
| */ |
| goog.net.tmpnetwork.testLoadImage = function(url, timeout, callback) { |
| var channelDebug = new goog.net.ChannelDebug(); |
| channelDebug.debug('TestLoadImage: loading ' + url); |
| var img = new Image(); |
| img.onload = function() { |
| try { |
| channelDebug.debug('TestLoadImage: loaded'); |
| goog.net.tmpnetwork.clearImageCallbacks_(img); |
| callback(true); |
| } catch (e) { |
| channelDebug.dumpException(e); |
| } |
| }; |
| img.onerror = function() { |
| try { |
| channelDebug.debug('TestLoadImage: error'); |
| goog.net.tmpnetwork.clearImageCallbacks_(img); |
| callback(false); |
| } catch (e) { |
| channelDebug.dumpException(e); |
| } |
| }; |
| img.onabort = function() { |
| try { |
| channelDebug.debug('TestLoadImage: abort'); |
| goog.net.tmpnetwork.clearImageCallbacks_(img); |
| callback(false); |
| } catch (e) { |
| channelDebug.dumpException(e); |
| } |
| }; |
| img.ontimeout = function() { |
| try { |
| channelDebug.debug('TestLoadImage: timeout'); |
| goog.net.tmpnetwork.clearImageCallbacks_(img); |
| callback(false); |
| } catch (e) { |
| channelDebug.dumpException(e); |
| } |
| }; |
| |
| goog.global.setTimeout(function() { |
| if (img.ontimeout) { |
| img.ontimeout(); |
| } |
| }, timeout); |
| img.src = url; |
| }; |
| |
| |
| /** |
| * Clear handlers to avoid memory leaks. |
| * @param {Image} img The image to clear handlers from. |
| * @private |
| */ |
| goog.net.tmpnetwork.clearImageCallbacks_ = function(img) { |
| // NOTE(user): Nullified individually to avoid compiler warnings |
| // (BUG 658126) |
| img.onload = null; |
| img.onerror = null; |
| img.onabort = null; |
| img.ontimeout = null; |
| }; |