src/main/resources/tunnel.js

   1
   2 /*
   3  *  Guacamole - Clientless Remote Desktop
   4  *  Copyright (C) 2010  Michael Jumper
   5  *
   6  *  This program is free software: you can redistribute it and/or modify
   7  *  it under the terms of the GNU Affero General Public License as published by
   8  *  the Free Software Foundation, either version 3 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU Affero General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU Affero General Public License
  17  */
  18
  19 function GuacamoleHTTPTunnel(tunnelURL) {
  20
  21     var TUNNEL_CONNECT = tunnelURL + "?connect";
  22     var TUNNEL_READ    = tunnelURL + "?read";
  23     var TUNNEL_WRITE   = tunnelURL + "?write";
  24
  25     var STATE_IDLE          = 0;
  26     var STATE_CONNECTED     = 1;
  27     var STATE_DISCONNECTED  = 2;
  28
  29     var currentState = STATE_IDLE;
  30
  31     var POLLING_ENABLED     = 1;
  32     var POLLING_DISABLED    = 0;
  33
  34     // Default to polling - will be turned off automatically if not needed
  35     var pollingMode = POLLING_ENABLED;
  36
  37     var instructionHandler = null;
  38
  39     var sendingMessages = 0;
  40     var outputMessageBuffer = "";
  41
  42     function sendMessage(message) {
  43
  44         // Do not attempt to send messages if not connected
  45         if (currentState != STATE_CONNECTED)
  46             return;
  47
  48         // Add event to queue, restart send loop if finished.
  49         outputMessageBuffer += message;
  50         if (sendingMessages == 0)
  51             sendPendingMessages();
  52
  53     }
  54
  55     function sendPendingMessages() {
  56
  57         if (outputMessageBuffer.length > 0) {
  58
  59             sendingMessages = 1;
  60
  61             var message_xmlhttprequest = new XMLHttpRequest();
  62             message_xmlhttprequest.open("POST", TUNNEL_WRITE);
  63             message_xmlhttprequest.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
  64             message_xmlhttprequest.setRequestHeader("Content-length", outputMessageBuffer.length);
  65
  66             // Once response received, send next queued event.
  67             message_xmlhttprequest.onreadystatechange = function() {
  68                 if (message_xmlhttprequest.readyState == 4)
  69                     sendPendingMessages();
  70             }
  71
  72             message_xmlhttprequest.send(outputMessageBuffer);
  73             outputMessageBuffer = ""; // Clear buffer
  74
  75         }
  76         else
  77             sendingMessages = 0;
  78
  79     }
  80
  81
  82     function handleResponse(xmlhttprequest) {
  83
  84         var interval = null;
  85         var nextRequest = null;
  86
  87         var dataUpdateEvents = 0;
  88         var instructionStart = 0;
  89         var startIndex = 0;
  90
  91         function parseResponse() {
  92
  93             // Do not handle responses if not connected
  94             if (currentState != STATE_CONNECTED) {
  95
  96                 // Clean up interval if polling
  97                 if (interval != null)
  98                     clearInterval(interval);
  99
 100                 return;
 101             }
 102
 103             // Start next request as soon as possible
 104             if (xmlhttprequest.readyState >= 2 && nextRequest == null)
 105                 nextRequest = makeRequest();
 106
 107             // Parse stream when data is received and when complete.
 108             if (xmlhttprequest.readyState == 3 ||
 109                 xmlhttprequest.readyState == 4) {
 110
 111                 // Also poll every 30ms (some browsers don't repeatedly call onreadystatechange for new data)
 112                 if (pollingMode == POLLING_ENABLED) {
 113                     if (xmlhttprequest.readyState == 3 && interval == null)
 114                         interval = setInterval(parseResponse, 30);
 115                     else if (xmlhttprequest.readyState == 4 && interval != null)
 116                         clearInterval(interval);
 117                 }
 118
 119                 // Halt on error during request
 120                 if (xmlhttprequest.status == 0 || xmlhttprequest.status != 200) {
 121                     disconnect();
 122                     return;
 123                 }
 124
 125                 var current = xmlhttprequest.responseText;
 126                 var instructionEnd;
 127
 128                 while ((instructionEnd = current.indexOf(";", startIndex)) != -1) {
 129
 130                     // Start next search at next instruction
 131                     startIndex = instructionEnd+1;
 132
 133                     var instruction = current.substr(instructionStart,
 134                             instructionEnd - instructionStart);
 135
 136                     instructionStart = startIndex;
 137
 138                     var opcodeEnd = instruction.indexOf(":");
 139
 140                     var opcode;
 141                     var parameters;
 142                     if (opcodeEnd == -1) {
 143                         opcode = instruction;
 144                         parameters = new Array();
 145                     }
 146                     else {
 147                         opcode = instruction.substr(0, opcodeEnd);
 148                         parameters = instruction.substr(opcodeEnd+1).split(",");
 149                     }
 150
 151                     // If we're done parsing, handle the next response.
 152                     if (opcode.length == 0) {
 153
 154                         delete xmlhttprequest;
 155                         if (nextRequest)
 156                             handleResponse(nextRequest);
 157
 158                         break;
 159                     }
 160
 161                     // Call instruction handler.
 162                     if (instructionHandler != null)
 163                         instructionHandler(opcode, parameters);
 164                 }
 165
 166                 // Start search at end of string.
 167                 startIndex = current.length;
 168
 169                 delete instruction;
 170                 delete parameters;
 171
 172             }
 173
 174         }
 175
 176         // If response polling enabled, attempt to detect if still
 177         // necessary (via wrapping parseResponse())
 178         if (pollingMode == POLLING_ENABLED) {
 179             xmlhttprequest.onreadystatechange = function() {
 180
 181                 // If we receive two or more readyState==3 events,
 182                 // there is no need to poll.
 183                 if (xmlhttprequest.readyState == 3) {
 184                     dataUpdateEvents++;
 185                     if (dataUpdateEvents >= 2) {
 186                         pollingMode = POLLING_DISABLED;
 187                         xmlhttprequest.onreadystatechange = parseResponse;
 188                     }
 189                 }
 190
 191                 parseResponse();
 192             }
 193         }
 194
 195         // Otherwise, just parse
 196         else
 197             xmlhttprequest.onreadystatechange = parseResponse;
 198
 199         parseResponse();
 200
 201     }
 202
 203
 204     function makeRequest() {
 205
 206         // Download self
 207         var xmlhttprequest = new XMLHttpRequest();
 208         xmlhttprequest.open("POST", TUNNEL_READ);
 209         xmlhttprequest.send(null);
 210
 211         return xmlhttprequest;
 212
 213     }
 214
 215     function connect() {
 216
 217         // Start tunnel and connect synchronously
 218         var connect_xmlhttprequest = new XMLHttpRequest();
 219         connect_xmlhttprequest.open("POST", TUNNEL_CONNECT, false);
 220         connect_xmlhttprequest.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
 221         connect_xmlhttprequest.setRequestHeader("Content-length", 0);
 222         connect_xmlhttprequest.send(null);
 223
 224         // Start reading data
 225         currentState = STATE_CONNECTED;
 226         handleResponse(makeRequest());
 227
 228     }
 229
 230     function disconnect() {
 231         currentState = STATE_DISCONNECTED;
 232     }
 233
 234     // External API
 235     this.connect = connect;
 236     this.disconnect = disconnect;
 237     this.sendMessage = sendMessage;
 238     this.setInstructionHandler = function(handler) {
 239         instructionHandler = handler;
 240     };
 241
 242 }