tcp-client: handle connection errors
[chrome-ext/music-player-client.git] / js / tcp-client.js
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1/*
2Copyright 2012 Google Inc.
3
4Licensed under the Apache License, Version 2.0 (the "License");
5you may not use this file except in compliance with the License.
6You may obtain a copy of the License at
7
8 http://www.apache.org/licenses/LICENSE-2.0
9
10Unless required by applicable law or agreed to in writing, software
11distributed under the License is distributed on an "AS IS" BASIS,
12WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13See the License for the specific language governing permissions and
14limitations under the License.
15
16Author: Boris Smus (smus@chromium.org)
17*/
18
19(function(exports) {
20
21 // Define some local variables here.
22 var socket = chrome.socket;
23
24 /**
25 * Creates an instance of the client
26 *
27 * @param {String} host The remote host to connect to
28 * @param {Number} port The port to connect to at the remote host
29 */
30 function TcpClient(host, port) {
31 this.host = host;
32 this.port = port;
33
34 // Callback functions.
35 this.callbacks = {
36 connect: null, // Called when socket is connected.
37 disconnect: null, // Called when socket is disconnected.
38 recv: null, // Called when client receives data from server.
39 sent: null // Called when client sends data to server.
40 };
41
42 // Socket.
43 this.socketId = null;
44 this.isConnected = false;
e7d6adb4 45 this.pollerId = null;
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46
47 log('initialized tcp client');
48 }
49
50 /**
51 * Connects to the TCP socket, and creates an open socket.
52 *
d4a26e73 53 * @see http://developer.chrome.com/apps/socket.html#method-create
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54 * @param {Function} callback The function to call on connection
55 */
56 TcpClient.prototype.connect = function(callback) {
57 socket.create('tcp', {}, this._onCreate.bind(this));
58
59 // Register connect callback.
60 this.callbacks.connect = callback;
61 };
62
63 /**
64 * Sends a message down the wire to the remote side
65 *
d4a26e73 66 * @see http://developer.chrome.com/apps/socket.html#method-write
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67 * @param {String} msg The message to send
68 * @param {Function} callback The function to call when the message has sent
69 */
70 TcpClient.prototype.sendMessage = function(msg, callback) {
71 this._stringToArrayBuffer(msg + '\n', function(arrayBuffer) {
72 socket.write(this.socketId, arrayBuffer, this._onWriteComplete.bind(this));
73 }.bind(this));
74
75 // Register sent callback.
76 this.callbacks.sent = callback;
77 };
78
79 /**
80 * Sets the callback for when a message is received
81 *
82 * @param {Function} callback The function to call when a message has arrived
83 */
84 TcpClient.prototype.addResponseListener = function(callback) {
85 // Register received callback.
86 this.callbacks.recv = callback;
87 };
88
89 /**
90 * Disconnects from the remote side
91 *
d4a26e73 92 * @see http://developer.chrome.com/apps/socket.html#method-disconnect
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93 */
94 TcpClient.prototype.disconnect = function() {
95 socket.disconnect(this.socketId);
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96 if (this.isConnected) {
97 clearInterval(this.pollerId);
98 this.pollerId = null;
99 this.isConnected = false;
100 }
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101 };
102
103 /**
104 * The callback function used for when we attempt to have Chrome
105 * create a socket. If the socket is successfully created
106 * we go ahead and connect to the remote side.
107 *
108 * @private
d4a26e73 109 * @see http://developer.chrome.com/apps/socket.html#method-connect
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110 * @param {Object} createInfo The socket details
111 */
112 TcpClient.prototype._onCreate = function(createInfo) {
113 this.socketId = createInfo.socketId;
114 if (this.socketId > 0) {
115 socket.connect(this.socketId, this.host, this.port, this._onConnectComplete.bind(this));
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116 } else {
117 error('Unable to create socket');
118 }
119 };
120
121 /**
122 * The callback function used for when we attempt to have Chrome
123 * connect to the remote side. If a successful connection is
124 * made then polling starts to check for data to read
125 *
126 * @private
127 * @param {Number} resultCode Indicates whether the connection was successful
128 */
129 TcpClient.prototype._onConnectComplete = function(resultCode) {
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130 log('resultCode: ' + resultCode);
131
132 // XXX: Can this ever be positive ?
133 this.isConnected = (resultCode >= 0);
134
50dafc4c 135 // Start polling for reads.
e7d6adb4 136 clearInterval(this.pollerId);
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137 if (this.isConnected) {
138 this.pollerId = setInterval(this.poll.bind(this), 500);
139 }
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140
141 if (this.callbacks.connect) {
142 log('connect complete');
fac1d771 143 this.callbacks.connect(resultCode);
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144 }
145 log('onConnectComplete');
146 };
147
148 /**
149 * Checks for new data to read from the socket
150 *
d4a26e73 151 * @see http://developer.chrome.com/apps/socket.html#method-read
50dafc4c 152 */
0a3a435e 153 TcpClient.prototype.poll = function() {
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154 socket.read(this.socketId, null, this._onDataRead.bind(this));
155 };
156
157 /**
158 * Callback function for when data has been read from the socket.
159 * Converts the array buffer that is read in to a string
160 * and sends it on for further processing by passing it to
161 * the previously assigned callback function.
162 *
163 * @private
164 * @see TcpClient.prototype.addResponseListener
165 * @param {Object} readInfo The incoming message
166 */
167 TcpClient.prototype._onDataRead = function(readInfo) {
168 // Call received callback if there's data in the response.
169 if (readInfo.resultCode > 0 && this.callbacks.recv) {
170 log('onDataRead');
171 // Convert ArrayBuffer to string.
172 this._arrayBufferToString(readInfo.data, function(str) {
173 this.callbacks.recv(str);
174 }.bind(this));
175 }
176 };
177
178 /**
179 * Callback for when data has been successfully
180 * written to the socket.
181 *
182 * @private
183 * @param {Object} writeInfo The outgoing message
184 */
185 TcpClient.prototype._onWriteComplete = function(writeInfo) {
186 log('onWriteComplete');
187 // Call sent callback.
188 if (this.callbacks.sent) {
189 this.callbacks.sent(writeInfo);
190 }
191 };
192
193 /**
194 * Converts an array buffer to a string
195 *
196 * @private
197 * @param {ArrayBuffer} buf The buffer to convert
198 * @param {Function} callback The function to call when conversion is complete
199 */
200 TcpClient.prototype._arrayBufferToString = function(buf, callback) {
201 var bb = new Blob([new Uint8Array(buf)]);
202 var f = new FileReader();
203 f.onload = function(e) {
204 callback(e.target.result);
205 };
206 f.readAsText(bb);
207 };
208
209 /**
210 * Converts a string to an array buffer
211 *
212 * @private
213 * @param {String} str The string to convert
214 * @param {Function} callback The function to call when conversion is complete
215 */
216 TcpClient.prototype._stringToArrayBuffer = function(str, callback) {
217 var bb = new Blob([str]);
218 var f = new FileReader();
219 f.onload = function(e) {
220 callback(e.target.result);
221 };
222 f.readAsArrayBuffer(bb);
223 };
224
225 /**
226 * Wrapper function for logging
227 */
228 function log(msg) {
fac1d771 229 //console.log('tcp-client:', msg);
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230 }
231
232 /**
233 * Wrapper function for error logging
234 */
235 function error(msg) {
fac1d771 236 console.error('tcp-client:', msg);
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237 }
238
239 exports.TcpClient = TcpClient;
240
241})(window);