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authorMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
committerMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
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Add m-esr52 at 52.6.0
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+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+const {classes: Cc, interfaces: Ci, utils: Cu} = Components;
+
+this.EXPORTED_SYMBOLS = [ "BingTranslator" ];
+
+Cu.import("resource://gre/modules/Services.jsm");
+Cu.import("resource://gre/modules/Log.jsm");
+Cu.import("resource://gre/modules/Promise.jsm");
+Cu.import("resource://gre/modules/Task.jsm");
+Cu.import("resource://services-common/utils.js");
+Cu.import("resource://gre/modules/Http.jsm");
+
+// The maximum amount of net data allowed per request on Bing's API.
+const MAX_REQUEST_DATA = 5000; // Documentation says 10000 but anywhere
+ // close to that is refused by the service.
+
+// The maximum number of chunks allowed to be translated in a single
+// request.
+const MAX_REQUEST_CHUNKS = 1000; // Documentation says 2000.
+
+// Self-imposed limit of 15 requests. This means that a page that would need
+// to be broken in more than 15 requests won't be fully translated.
+// The maximum amount of data that we will translate for a single page
+// is MAX_REQUESTS * MAX_REQUEST_DATA.
+const MAX_REQUESTS = 15;
+
+/**
+ * Translates a webpage using Bing's Translation API.
+ *
+ * @param translationDocument The TranslationDocument object that represents
+ * the webpage to be translated
+ * @param sourceLanguage The source language of the document
+ * @param targetLanguage The target language for the translation
+ *
+ * @returns {Promise} A promise that will resolve when the translation
+ * task is finished.
+ */
+this.BingTranslator = function(translationDocument, sourceLanguage, targetLanguage) {
+ this.translationDocument = translationDocument;
+ this.sourceLanguage = sourceLanguage;
+ this.targetLanguage = targetLanguage;
+ this._pendingRequests = 0;
+ this._partialSuccess = false;
+ this._serviceUnavailable = false;
+ this._translatedCharacterCount = 0;
+};
+
+this.BingTranslator.prototype = {
+ /**
+ * Performs the translation, splitting the document into several chunks
+ * respecting the data limits of the API.
+ *
+ * @returns {Promise} A promise that will resolve when the translation
+ * task is finished.
+ */
+ translate: function() {
+ return Task.spawn(function *() {
+ let currentIndex = 0;
+ this._onFinishedDeferred = Promise.defer();
+
+ // Let's split the document into various requests to be sent to
+ // Bing's Translation API.
+ for (let requestCount = 0; requestCount < MAX_REQUESTS; requestCount++) {
+ // Generating the text for each request can be expensive, so
+ // let's take the opportunity of the chunkification process to
+ // allow for the event loop to attend other pending events
+ // before we continue.
+ yield CommonUtils.laterTickResolvingPromise();
+
+ // Determine the data for the next request.
+ let request = this._generateNextTranslationRequest(currentIndex);
+
+ // Create a real request to the server, and put it on the
+ // pending requests list.
+ let bingRequest = new BingRequest(request.data,
+ this.sourceLanguage,
+ this.targetLanguage);
+ this._pendingRequests++;
+ bingRequest.fireRequest().then(this._chunkCompleted.bind(this),
+ this._chunkFailed.bind(this));
+
+ currentIndex = request.lastIndex;
+ if (request.finished) {
+ break;
+ }
+ }
+
+ return this._onFinishedDeferred.promise;
+ }.bind(this));
+ },
+
+ /**
+ * Resets the expiration time of the current token, in order to
+ * force the token manager to ask for a new token during the next request.
+ */
+ _resetToken : function() {
+ // Force the token manager to get update token
+ BingTokenManager._currentExpiryTime = 0;
+ },
+
+ /**
+ * Function called when a request sent to the server completed successfully.
+ * This function handles calling the function to parse the result and the
+ * function to resolve the promise returned by the public `translate()`
+ * method when there's no pending request left.
+ *
+ * @param request The BingRequest sent to the server.
+ */
+ _chunkCompleted: function(bingRequest) {
+ if (this._parseChunkResult(bingRequest)) {
+ this._partialSuccess = true;
+ // Count the number of characters successfully translated.
+ this._translatedCharacterCount += bingRequest.characterCount;
+ }
+
+ this._checkIfFinished();
+ },
+
+ /**
+ * Function called when a request sent to the server has failed.
+ * This function handles deciding if the error is transient or means the
+ * service is unavailable (zero balance on the key or request credentials are
+ * not in an active state) and calling the function to resolve the promise
+ * returned by the public `translate()` method when there's no pending.
+ * request left.
+ *
+ * @param aError [optional] The XHR object of the request that failed.
+ */
+ _chunkFailed: function(aError) {
+ if (aError instanceof Ci.nsIXMLHttpRequest &&
+ [400, 401].indexOf(aError.status) != -1) {
+ let body = aError.responseText;
+ if (body && body.includes("TranslateApiException") &&
+ (body.includes("balance") || body.includes("active state")))
+ this._serviceUnavailable = true;
+ }
+
+ this._checkIfFinished();
+ },
+
+ /**
+ * Function called when a request sent to the server has completed.
+ * This function handles resolving the promise
+ * returned by the public `translate()` method when all chunks are completed.
+ */
+ _checkIfFinished: function() {
+ // Check if all pending requests have been
+ // completed and then resolves the promise.
+ // If at least one chunk was successful, the
+ // promise will be resolved positively which will
+ // display the "Success" state for the infobar. Otherwise,
+ // the "Error" state will appear.
+ if (--this._pendingRequests == 0) {
+ if (this._partialSuccess) {
+ this._onFinishedDeferred.resolve({
+ characterCount: this._translatedCharacterCount
+ });
+ } else {
+ let error = this._serviceUnavailable ? "unavailable" : "failure";
+ this._onFinishedDeferred.reject(error);
+ }
+ }
+ },
+
+ /**
+ * This function parses the result returned by Bing's Http.svc API,
+ * which is a XML file that contains a number of elements. To our
+ * particular interest, the only part of the response that matters
+ * are the <TranslatedText> nodes, which contains the resulting
+ * items that were sent to be translated.
+ *
+ * @param request The request sent to the server.
+ * @returns boolean True if parsing of this chunk was successful.
+ */
+ _parseChunkResult: function(bingRequest) {
+ let results;
+ try {
+ let doc = bingRequest.networkRequest.responseXML;
+ results = doc.querySelectorAll("TranslatedText");
+ } catch (e) {
+ return false;
+ }
+
+ let len = results.length;
+ if (len != bingRequest.translationData.length) {
+ // This should never happen, but if the service returns a different number
+ // of items (from the number of items submitted), we can't use this chunk
+ // because all items would be paired incorrectly.
+ return false;
+ }
+
+ let error = false;
+ for (let i = 0; i < len; i++) {
+ try {
+ let result = results[i].firstChild.nodeValue;
+ let root = bingRequest.translationData[i][0];
+
+ if (root.isSimpleRoot) {
+ // Workaround for Bing's service problem in which "&" chars in
+ // plain-text TranslationItems are double-escaped.
+ result = result.replace(/&amp;/g, "&");
+ }
+
+ root.parseResult(result);
+ } catch (e) { error = true; }
+ }
+
+ return !error;
+ },
+
+ /**
+ * This function will determine what is the data to be used for
+ * the Nth request we are generating, based on the input params.
+ *
+ * @param startIndex What is the index, in the roots list, that the
+ * chunk should start.
+ */
+ _generateNextTranslationRequest: function(startIndex) {
+ let currentDataSize = 0;
+ let currentChunks = 0;
+ let output = [];
+ let rootsList = this.translationDocument.roots;
+
+ for (let i = startIndex; i < rootsList.length; i++) {
+ let root = rootsList[i];
+ let text = this.translationDocument.generateTextForItem(root);
+ if (!text) {
+ continue;
+ }
+
+ text = escapeXML(text);
+ let newCurSize = currentDataSize + text.length;
+ let newChunks = currentChunks + 1;
+
+ if (newCurSize > MAX_REQUEST_DATA ||
+ newChunks > MAX_REQUEST_CHUNKS) {
+
+ // If we've reached the API limits, let's stop accumulating data
+ // for this request and return. We return information useful for
+ // the caller to pass back on the next call, so that the function
+ // can keep working from where it stopped.
+ return {
+ data: output,
+ finished: false,
+ lastIndex: i
+ };
+ }
+
+ currentDataSize = newCurSize;
+ currentChunks = newChunks;
+ output.push([root, text]);
+ }
+
+ return {
+ data: output,
+ finished: true,
+ lastIndex: 0
+ };
+ }
+};
+
+/**
+ * Represents a request (for 1 chunk) sent off to Bing's service.
+ *
+ * @params translationData The data to be used for this translation,
+ * generated by the generateNextTranslationRequest...
+ * function.
+ * @param sourceLanguage The source language of the document.
+ * @param targetLanguage The target language for the translation.
+ *
+ */
+function BingRequest(translationData, sourceLanguage, targetLanguage) {
+ this.translationData = translationData;
+ this.sourceLanguage = sourceLanguage;
+ this.targetLanguage = targetLanguage;
+ this.characterCount = 0;
+}
+
+BingRequest.prototype = {
+ /**
+ * Initiates the request
+ */
+ fireRequest: function() {
+ return Task.spawn(function *() {
+ // Prepare authentication.
+ let token = yield BingTokenManager.getToken();
+ let auth = "Bearer " + token;
+
+ // Prepare URL.
+ let url = getUrlParam("https://api.microsofttranslator.com/v2/Http.svc/TranslateArray",
+ "browser.translation.bing.translateArrayURL");
+
+ // Prepare request headers.
+ let headers = [["Content-type", "text/xml"], ["Authorization", auth]];
+
+ // Prepare the request body.
+ let requestString =
+ '<TranslateArrayRequest>' +
+ '<AppId/>' +
+ '<From>' + this.sourceLanguage + '</From>' +
+ '<Options>' +
+ '<ContentType xmlns="http://schemas.datacontract.org/2004/07/Microsoft.MT.Web.Service.V2">text/html</ContentType>' +
+ '<ReservedFlags xmlns="http://schemas.datacontract.org/2004/07/Microsoft.MT.Web.Service.V2" />' +
+ '</Options>' +
+ '<Texts xmlns:s="http://schemas.microsoft.com/2003/10/Serialization/Arrays">';
+
+ for (let [, text] of this.translationData) {
+ requestString += '<s:string>' + text + '</s:string>';
+ this.characterCount += text.length;
+ }
+
+ requestString += '</Texts>' +
+ '<To>' + this.targetLanguage + '</To>' +
+ '</TranslateArrayRequest>';
+
+ // Set up request options.
+ let deferred = Promise.defer();
+ let options = {
+ onLoad: (function(responseText, xhr) {
+ deferred.resolve(this);
+ }).bind(this),
+ onError: function(e, responseText, xhr) {
+ deferred.reject(xhr);
+ },
+ postData: requestString,
+ headers: headers
+ };
+
+ // Fire the request.
+ let request = httpRequest(url, options);
+
+ // Override the response MIME type.
+ request.overrideMimeType("text/xml");
+ this.networkRequest = request;
+ return deferred.promise;
+ }.bind(this));
+ }
+};
+
+/**
+ * Authentication Token manager for the API
+ */
+var BingTokenManager = {
+ _currentToken: null,
+ _currentExpiryTime: 0,
+ _pendingRequest: null,
+
+ /**
+ * Get a valid, non-expired token to be used for the API calls.
+ *
+ * @returns {Promise} A promise that resolves with the token
+ * string once it is obtained. The token returned
+ * can be the same one used in the past if it is still
+ * valid.
+ */
+ getToken: function() {
+ if (this._pendingRequest) {
+ return this._pendingRequest;
+ }
+
+ let remainingMs = this._currentExpiryTime - new Date();
+ // Our existing token is still good for more than a minute, let's use it.
+ if (remainingMs > 60 * 1000) {
+ return Promise.resolve(this._currentToken);
+ }
+
+ return this._getNewToken();
+ },
+
+ /**
+ * Generates a new token from the server.
+ *
+ * @returns {Promise} A promise that resolves with the token
+ * string once it is obtained.
+ */
+ _getNewToken: function() {
+ let url = getUrlParam("https://datamarket.accesscontrol.windows.net/v2/OAuth2-13",
+ "browser.translation.bing.authURL");
+ let params = [
+ ["grant_type", "client_credentials"],
+ ["scope", "http://api.microsofttranslator.com"],
+ ["client_id",
+ getUrlParam("%BING_API_CLIENTID%", "browser.translation.bing.clientIdOverride")],
+ ["client_secret",
+ getUrlParam("%BING_API_KEY%", "browser.translation.bing.apiKeyOverride")]
+ ];
+
+ let deferred = Promise.defer();
+ let options = {
+ onLoad: function(responseText, xhr) {
+ BingTokenManager._pendingRequest = null;
+ try {
+ let json = JSON.parse(responseText);
+
+ if (json.error) {
+ deferred.reject(json.error);
+ return;
+ }
+
+ let token = json.access_token;
+ let expires_in = json.expires_in;
+ BingTokenManager._currentToken = token;
+ BingTokenManager._currentExpiryTime = new Date(Date.now() + expires_in * 1000);
+ deferred.resolve(token);
+ } catch (e) {
+ deferred.reject(e);
+ }
+ },
+ onError: function(e, responseText, xhr) {
+ BingTokenManager._pendingRequest = null;
+ deferred.reject(e);
+ },
+ postData: params
+ };
+
+ this._pendingRequest = deferred.promise;
+ httpRequest(url, options);
+
+ return deferred.promise;
+ }
+};
+
+/**
+ * Escape a string to be valid XML content.
+ */
+function escapeXML(aStr) {
+ return aStr.toString()
+ .replace(/&/g, "&amp;")
+ .replace(/\"/g, "&quot;")
+ .replace(/\'/g, "&apos;")
+ .replace(/</g, "&lt;")
+ .replace(/>/g, "&gt;");
+}
+
+/**
+ * Fetch an auth token (clientID or client secret), which may be overridden by
+ * a pref if it's set.
+ */
+function getUrlParam(paramValue, prefName) {
+ if (Services.prefs.getPrefType(prefName))
+ paramValue = Services.prefs.getCharPref(prefName);
+ paramValue = Services.urlFormatter.formatURL(paramValue);
+ return paramValue;
+}