+/*
+Copyright 2012 Google Inc.
+
+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.
+
+Author: Boris Smus (smus@chromium.org)
+*/
+
+(function(exports) {
+
+ // Define some local variables here.
+ var socket = chrome.socket;
+
+ /**
+ * Creates an instance of the client
+ *
+ * @param {String} host The remote host to connect to
+ * @param {Number} port The port to connect to at the remote host
+ */
+ function TcpClient(host, port) {
+ this.host = host;
+ this.port = port;
+
+ // Callback functions.
+ this.callbacks = {
+ connect: null, // Called when socket is connected.
+ disconnect: null, // Called when socket is disconnected.
+ recv: null, // Called when client receives data from server.
+ sent: null // Called when client sends data to server.
+ };
+
+ // Socket.
+ this.socketId = null;
+ this.isConnected = false;
+
+ log('initialized tcp client');
+ }
+
+ /**
+ * Connects to the TCP socket, and creates an open socket.
+ *
+ * @see http://developer.chrome.com/trunk/apps/socket.html#method-create
+ * @param {Function} callback The function to call on connection
+ */
+ TcpClient.prototype.connect = function(callback) {
+ socket.create('tcp', {}, this._onCreate.bind(this));
+
+ // Register connect callback.
+ this.callbacks.connect = callback;
+ };
+
+ /**
+ * Sends a message down the wire to the remote side
+ *
+ * @see http://developer.chrome.com/trunk/apps/socket.html#method-write
+ * @param {String} msg The message to send
+ * @param {Function} callback The function to call when the message has sent
+ */
+ TcpClient.prototype.sendMessage = function(msg, callback) {
+ this._stringToArrayBuffer(msg + '\n', function(arrayBuffer) {
+ socket.write(this.socketId, arrayBuffer, this._onWriteComplete.bind(this));
+ }.bind(this));
+
+ // Register sent callback.
+ this.callbacks.sent = callback;
+ };
+
+ /**
+ * Sets the callback for when a message is received
+ *
+ * @param {Function} callback The function to call when a message has arrived
+ */
+ TcpClient.prototype.addResponseListener = function(callback) {
+ // Register received callback.
+ this.callbacks.recv = callback;
+ };
+
+ /**
+ * Disconnects from the remote side
+ *
+ * @see http://developer.chrome.com/trunk/apps/socket.html#method-disconnect
+ */
+ TcpClient.prototype.disconnect = function() {
+ socket.disconnect(this.socketId);
+ this.isConnected = false;
+ };
+
+ /**
+ * The callback function used for when we attempt to have Chrome
+ * create a socket. If the socket is successfully created
+ * we go ahead and connect to the remote side.
+ *
+ * @private
+ * @see http://developer.chrome.com/trunk/apps/socket.html#method-connect
+ * @param {Object} createInfo The socket details
+ */
+ TcpClient.prototype._onCreate = function(createInfo) {
+ this.socketId = createInfo.socketId;
+ if (this.socketId > 0) {
+ socket.connect(this.socketId, this.host, this.port, this._onConnectComplete.bind(this));
+ this.isConnected = true;
+ } else {
+ error('Unable to create socket');
+ }
+ };
+
+ /**
+ * The callback function used for when we attempt to have Chrome
+ * connect to the remote side. If a successful connection is
+ * made then polling starts to check for data to read
+ *
+ * @private
+ * @param {Number} resultCode Indicates whether the connection was successful
+ */
+ TcpClient.prototype._onConnectComplete = function(resultCode) {
+ // Start polling for reads.
+ setInterval(this._periodicallyRead.bind(this), 500);
+
+ if (this.callbacks.connect) {
+ log('connect complete');
+ this.callbacks.connect();
+ }
+ log('onConnectComplete');
+ };
+
+ /**
+ * Checks for new data to read from the socket
+ *
+ * @see http://developer.chrome.com/trunk/apps/socket.html#method-read
+ */
+ TcpClient.prototype._periodicallyRead = function() {
+ socket.read(this.socketId, null, this._onDataRead.bind(this));
+ };
+
+ /**
+ * Callback function for when data has been read from the socket.
+ * Converts the array buffer that is read in to a string
+ * and sends it on for further processing by passing it to
+ * the previously assigned callback function.
+ *
+ * @private
+ * @see TcpClient.prototype.addResponseListener
+ * @param {Object} readInfo The incoming message
+ */
+ TcpClient.prototype._onDataRead = function(readInfo) {
+ // Call received callback if there's data in the response.
+ if (readInfo.resultCode > 0 && this.callbacks.recv) {
+ log('onDataRead');
+ // Convert ArrayBuffer to string.
+ this._arrayBufferToString(readInfo.data, function(str) {
+ this.callbacks.recv(str);
+ }.bind(this));
+ }
+ };
+
+ /**
+ * Callback for when data has been successfully
+ * written to the socket.
+ *
+ * @private
+ * @param {Object} writeInfo The outgoing message
+ */
+ TcpClient.prototype._onWriteComplete = function(writeInfo) {
+ log('onWriteComplete');
+ // Call sent callback.
+ if (this.callbacks.sent) {
+ this.callbacks.sent(writeInfo);
+ }
+ };
+
+ /**
+ * Converts an array buffer to a string
+ *
+ * @private
+ * @param {ArrayBuffer} buf The buffer to convert
+ * @param {Function} callback The function to call when conversion is complete
+ */
+ TcpClient.prototype._arrayBufferToString = function(buf, callback) {
+ var bb = new Blob([new Uint8Array(buf)]);
+ var f = new FileReader();
+ f.onload = function(e) {
+ callback(e.target.result);
+ };
+ f.readAsText(bb);
+ };
+
+ /**
+ * Converts a string to an array buffer
+ *
+ * @private
+ * @param {String} str The string to convert
+ * @param {Function} callback The function to call when conversion is complete
+ */
+ TcpClient.prototype._stringToArrayBuffer = function(str, callback) {
+ var bb = new Blob([str]);
+ var f = new FileReader();
+ f.onload = function(e) {
+ callback(e.target.result);
+ };
+ f.readAsArrayBuffer(bb);
+ };
+
+ /**
+ * Wrapper function for logging
+ */
+ function log(msg) {
+ //console.log('tcp-client: ', msg);
+ }
+
+ /**
+ * Wrapper function for error logging
+ */
+ function error(msg) {
+ console.error('tcp-client: ', msg);
+ }
+
+ exports.TcpClient = TcpClient;
+
+})(window);