/**
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* Socket implementation that uses flash SocketPool class as a backend.
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*
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* @author Dave Longley
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*
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* Copyright (c) 2010-2013 Digital Bazaar, Inc.
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*/
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var forge = require('./forge');
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require('./util');
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// define net namespace
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var net = module.exports = forge.net = forge.net || {};
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// map of flash ID to socket pool
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net.socketPools = {};
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/**
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* Creates a flash socket pool.
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*
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* @param options:
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* flashId: the dom ID for the flash object element.
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* policyPort: the default policy port for sockets, 0 to use the
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* flash default.
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* policyUrl: the default policy file URL for sockets (if provided
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* used instead of a policy port).
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* msie: true if the browser is msie, false if not.
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*
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* @return the created socket pool.
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*/
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net.createSocketPool = function(options) {
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// set default
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options.msie = options.msie || false;
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// initialize the flash interface
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var spId = options.flashId;
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var api = document.getElementById(spId);
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api.init({marshallExceptions: !options.msie});
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// create socket pool entry
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var sp = {
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// ID of the socket pool
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id: spId,
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// flash interface
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flashApi: api,
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// map of socket ID to sockets
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sockets: {},
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// default policy port
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policyPort: options.policyPort || 0,
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// default policy URL
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policyUrl: options.policyUrl || null
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};
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net.socketPools[spId] = sp;
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// create event handler, subscribe to flash events
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if(options.msie === true) {
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sp.handler = function(e) {
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if(e.id in sp.sockets) {
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// get handler function
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var f;
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switch(e.type) {
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case 'connect':
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f = 'connected';
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break;
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case 'close':
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f = 'closed';
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break;
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case 'socketData':
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f = 'data';
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break;
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default:
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f = 'error';
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break;
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}
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/* IE calls javascript on the thread of the external object
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that triggered the event (in this case flash) ... which will
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either run concurrently with other javascript or pre-empt any
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running javascript in the middle of its execution (BAD!) ...
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calling setTimeout() will schedule the javascript to run on
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the javascript thread and solve this EVIL problem. */
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setTimeout(function() {sp.sockets[e.id][f](e);}, 0);
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}
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};
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} else {
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sp.handler = function(e) {
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if(e.id in sp.sockets) {
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// get handler function
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var f;
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switch(e.type) {
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case 'connect':
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f = 'connected';
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break;
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case 'close':
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f = 'closed';
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break;
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case 'socketData':
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f = 'data';
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break;
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default:
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f = 'error';
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break;
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}
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sp.sockets[e.id][f](e);
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}
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};
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}
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var handler = 'forge.net.socketPools[\'' + spId + '\'].handler';
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api.subscribe('connect', handler);
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api.subscribe('close', handler);
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api.subscribe('socketData', handler);
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api.subscribe('ioError', handler);
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api.subscribe('securityError', handler);
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/**
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* Destroys a socket pool. The socket pool still needs to be cleaned
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* up via net.cleanup().
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*/
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sp.destroy = function() {
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delete net.socketPools[options.flashId];
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for(var id in sp.sockets) {
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sp.sockets[id].destroy();
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}
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sp.sockets = {};
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api.cleanup();
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};
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/**
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* Creates a new socket.
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*
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* @param options:
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* connected: function(event) called when the socket connects.
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* closed: function(event) called when the socket closes.
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* data: function(event) called when socket data has arrived,
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* it can be read from the socket using receive().
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* error: function(event) called when a socket error occurs.
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*/
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sp.createSocket = function(options) {
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// default to empty options
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options = options || {};
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// create flash socket
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var id = api.create();
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// create javascript socket wrapper
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var socket = {
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id: id,
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// set handlers
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connected: options.connected || function(e) {},
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closed: options.closed || function(e) {},
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data: options.data || function(e) {},
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error: options.error || function(e) {}
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};
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/**
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* Destroys this socket.
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*/
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socket.destroy = function() {
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api.destroy(id);
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delete sp.sockets[id];
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};
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/**
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* Connects this socket.
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*
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* @param options:
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* host: the host to connect to.
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* port: the port to connect to.
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* policyPort: the policy port to use (if non-default), 0 to
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* use the flash default.
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* policyUrl: the policy file URL to use (instead of port).
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*/
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socket.connect = function(options) {
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// give precedence to policy URL over policy port
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// if no policy URL and passed port isn't 0, use default port,
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// otherwise use 0 for the port
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var policyUrl = options.policyUrl || null;
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var policyPort = 0;
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if(policyUrl === null && options.policyPort !== 0) {
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policyPort = options.policyPort || sp.policyPort;
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}
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api.connect(id, options.host, options.port, policyPort, policyUrl);
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};
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/**
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* Closes this socket.
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*/
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socket.close = function() {
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api.close(id);
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socket.closed({
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id: socket.id,
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type: 'close',
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bytesAvailable: 0
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});
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};
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/**
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* Determines if the socket is connected or not.
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*
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* @return true if connected, false if not.
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*/
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socket.isConnected = function() {
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return api.isConnected(id);
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};
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/**
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* Writes bytes to this socket.
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*
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* @param bytes the bytes (as a string) to write.
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*
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* @return true on success, false on failure.
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*/
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socket.send = function(bytes) {
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return api.send(id, forge.util.encode64(bytes));
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};
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/**
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* Reads bytes from this socket (non-blocking). Fewer than the number
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* of bytes requested may be read if enough bytes are not available.
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*
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* This method should be called from the data handler if there are
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* enough bytes available. To see how many bytes are available, check
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* the 'bytesAvailable' property on the event in the data handler or
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* call the bytesAvailable() function on the socket. If the browser is
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* msie, then the bytesAvailable() function should be used to avoid
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* race conditions. Otherwise, using the property on the data handler's
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* event may be quicker.
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*
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* @param count the maximum number of bytes to read.
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*
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* @return the bytes read (as a string) or null on error.
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*/
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socket.receive = function(count) {
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var rval = api.receive(id, count).rval;
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return (rval === null) ? null : forge.util.decode64(rval);
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};
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/**
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* Gets the number of bytes available for receiving on the socket.
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*
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* @return the number of bytes available for receiving.
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*/
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socket.bytesAvailable = function() {
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return api.getBytesAvailable(id);
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};
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// store and return socket
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sp.sockets[id] = socket;
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return socket;
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};
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return sp;
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};
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/**
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* Destroys a flash socket pool.
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*
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* @param options:
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* flashId: the dom ID for the flash object element.
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*/
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net.destroySocketPool = function(options) {
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if(options.flashId in net.socketPools) {
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var sp = net.socketPools[options.flashId];
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sp.destroy();
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}
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};
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/**
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* Creates a new socket.
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*
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* @param options:
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* flashId: the dom ID for the flash object element.
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* connected: function(event) called when the socket connects.
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* closed: function(event) called when the socket closes.
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* data: function(event) called when socket data has arrived, it
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* can be read from the socket using receive().
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* error: function(event) called when a socket error occurs.
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*
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* @return the created socket.
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*/
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net.createSocket = function(options) {
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var socket = null;
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if(options.flashId in net.socketPools) {
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// get related socket pool
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var sp = net.socketPools[options.flashId];
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socket = sp.createSocket(options);
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}
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return socket;
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};
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