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1 | /* |
2 | * Licensed to the Apache Software Foundation (ASF) under one | |
3 | * or more contributor license agreements. See the NOTICE file | |
4 | * distributed with this work for additional information | |
5 | * regarding copyright ownership. The ASF licenses this file | |
6 | * to you under the Apache License, Version 2.0 (the | |
7 | * "License"); you may not use this file except in compliance | |
8 | * with the License. You may obtain a copy of the License at | |
9 | * | |
10 | * http://www.apache.org/licenses/LICENSE-2.0 | |
11 | * | |
12 | * Unless required by applicable law or agreed to in writing, | |
13 | * software distributed under the License is distributed on an | |
14 | * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY | |
15 | * KIND, either express or implied. See the License for the | |
16 | * specific language governing permissions and limitations | |
17 | * under the License. | |
18 | */ | |
19 | ||
20 | var log = require('./log'); | |
21 | ||
22 | module.exports = TWebSocketTransport; | |
23 | ||
24 | /** | |
25 | * Constructor Function for the WebSocket transport. | |
26 | * @constructor | |
27 | * @param {string} [url] - The URL to connect to. | |
28 | * @classdesc The Apache Thrift Transport layer performs byte level I/O | |
29 | * between RPC clients and servers. The JavaScript TWebSocketTransport object | |
30 | * uses the WebSocket protocol. Target servers must implement WebSocket. | |
31 | * (see: node.js example server_http.js). | |
32 | * @example | |
33 | * var transport = new Thrift.TWebSocketTransport("http://localhost:8585"); | |
34 | */ | |
35 | function TWebSocketTransport(url) { | |
36 | this.__reset(url); | |
37 | }; | |
38 | ||
39 | ||
40 | TWebSocketTransport.prototype.__reset = function(url) { | |
41 | this.url = url; //Where to connect | |
42 | this.socket = null; //The web socket | |
43 | this.callbacks = []; //Pending callbacks | |
44 | this.send_pending = []; //Buffers/Callback pairs waiting to be sent | |
45 | this.send_buf = ''; //Outbound data, immutable until sent | |
46 | this.recv_buf = ''; //Inbound data | |
47 | this.rb_wpos = 0; //Network write position in receive buffer | |
48 | this.rb_rpos = 0; //Client read position in receive buffer | |
49 | }; | |
50 | ||
51 | /** | |
52 | * Sends the current WS request and registers callback. The async | |
53 | * parameter is ignored (WS flush is always async) and the callback | |
54 | * function parameter is required. | |
55 | * @param {object} async - Ignored. | |
56 | * @param {object} callback - The client completion callback. | |
57 | * @returns {undefined|string} Nothing (undefined) | |
58 | */ | |
59 | TWebSocketTransport.prototype.flush = function(async, callback) { | |
60 | var self = this; | |
61 | if (this.isOpen()) { | |
62 | //Send data and register a callback to invoke the client callback | |
63 | this.socket.send(this.send_buf); | |
64 | this.callbacks.push((function() { | |
65 | var clientCallback = callback; | |
66 | return function(msg) { | |
67 | self.setRecvBuffer(msg); | |
68 | clientCallback(); | |
69 | }; | |
70 | }())); | |
71 | } else { | |
72 | //Queue the send to go out __onOpen | |
73 | this.send_pending.push({ | |
74 | buf: this.send_buf, | |
75 | cb: callback | |
76 | }); | |
77 | } | |
78 | }; | |
79 | ||
80 | TWebSocketTransport.prototype.__onOpen = function() { | |
81 | var self = this; | |
82 | if (this.send_pending.length > 0) { | |
83 | //If the user made calls before the connection was fully | |
84 | //open, send them now | |
85 | this.send_pending.forEach(function(elem) { | |
86 | this.socket.send(elem.buf); | |
87 | this.callbacks.push((function() { | |
88 | var clientCallback = elem.cb; | |
89 | return function(msg) { | |
90 | self.setRecvBuffer(msg); | |
91 | clientCallback(); | |
92 | }; | |
93 | }())); | |
94 | }); | |
95 | this.send_pending = []; | |
96 | } | |
97 | }; | |
98 | ||
99 | TWebSocketTransport.prototype.__onClose = function(evt) { | |
100 | this.__reset(this.url); | |
101 | }; | |
102 | ||
103 | TWebSocketTransport.prototype.__onMessage = function(evt) { | |
104 | if (this.callbacks.length) { | |
105 | this.callbacks.shift()(evt.data); | |
106 | } | |
107 | }; | |
108 | ||
109 | TWebSocketTransport.prototype.__onError = function(evt) { | |
110 | log.error('websocket: ' + evt.toString()); | |
111 | this.socket.close(); | |
112 | }; | |
113 | ||
114 | /** | |
115 | * Sets the buffer to use when receiving server responses. | |
116 | * @param {string} buf - The buffer to receive server responses. | |
117 | */ | |
118 | TWebSocketTransport.prototype.setRecvBuffer = function(buf) { | |
119 | this.recv_buf = buf; | |
120 | this.recv_buf_sz = this.recv_buf.length; | |
121 | this.wpos = this.recv_buf.length; | |
122 | this.rpos = 0; | |
123 | }; | |
124 | ||
125 | /** | |
126 | * Returns true if the transport is open | |
127 | * @readonly | |
128 | * @returns {boolean} | |
129 | */ | |
130 | TWebSocketTransport.prototype.isOpen = function() { | |
131 | return this.socket && this.socket.readyState == this.socket.OPEN; | |
132 | }; | |
133 | ||
134 | /** | |
135 | * Opens the transport connection | |
136 | */ | |
137 | TWebSocketTransport.prototype.open = function() { | |
138 | //If OPEN/CONNECTING/CLOSING ignore additional opens | |
139 | if (this.socket && this.socket.readyState != this.socket.CLOSED) { | |
140 | return; | |
141 | } | |
142 | //If there is no socket or the socket is closed: | |
143 | this.socket = new WebSocket(this.url); | |
144 | this.socket.onopen = this.__onOpen.bind(this); | |
145 | this.socket.onmessage = this.__onMessage.bind(this); | |
146 | this.socket.onerror = this.__onError.bind(this); | |
147 | this.socket.onclose = this.__onClose.bind(this); | |
148 | }; | |
149 | ||
150 | /** | |
151 | * Closes the transport connection | |
152 | */ | |
153 | TWebSocketTransport.prototype.close = function() { | |
154 | this.socket.close(); | |
155 | }; | |
156 | ||
157 | /** | |
158 | * Returns the specified number of characters from the response | |
159 | * buffer. | |
160 | * @param {number} len - The number of characters to return. | |
161 | * @returns {string} Characters sent by the server. | |
162 | */ | |
163 | TWebSocketTransport.prototype.read = function(len) { | |
164 | var avail = this.wpos - this.rpos; | |
165 | ||
166 | if (avail === 0) { | |
167 | return ''; | |
168 | } | |
169 | ||
170 | var give = len; | |
171 | ||
172 | if (avail < len) { | |
173 | give = avail; | |
174 | } | |
175 | ||
176 | var ret = this.read_buf.substr(this.rpos, give); | |
177 | this.rpos += give; | |
178 | ||
179 | //clear buf when complete? | |
180 | return ret; | |
181 | }; | |
182 | ||
183 | /** | |
184 | * Returns the entire response buffer. | |
185 | * @returns {string} Characters sent by the server. | |
186 | */ | |
187 | TWebSocketTransport.prototype.readAll = function() { | |
188 | return this.recv_buf; | |
189 | }; | |
190 | ||
191 | /** | |
192 | * Sets the send buffer to buf. | |
193 | * @param {string} buf - The buffer to send. | |
194 | */ | |
195 | TWebSocketTransport.prototype.write = function(buf) { | |
196 | this.send_buf = buf; | |
197 | }; | |
198 | ||
199 | /** | |
200 | * Returns the send buffer. | |
201 | * @readonly | |
202 | * @returns {string} The send buffer. | |
203 | */ | |
204 | TWebSocketTransport.prototype.getSendBuffer = function() { | |
205 | return this.send_buf; | |
206 | }; |