AngularJS service to connect to a websocket server (SockJS or pure WebSocket), manage reconnection, and allow the rest of the angular application to easily send/retrieve data from an open socket.

angular-socket.js

//TODO: make this a module

/**
 * # SockJS socket management service
 *
 * Creates SockJS socket connection to server, re-connects on disconnection,
 * and exports hooks to map handlers for various data interactions.
 *
 */
angular.module('app').factory
    ( 'socketService'
    , [ '$rootScope'
      , '$log'
    , function
        ( $rootScope
        , $log
        ){
            var createSocket = function(){

                // Get reference to port.
                var port = (location.port != 80) ? ':' + location.port : '';

                socket = new SockJS
                    ( '//' + document.domain + '' + port + '/api'
                    , ''
                    , { 'debug':true
                        , 'devel' : true
                        , 'protocols_whitelist':
                            [ 'xdr-streaming'
                            , 'xdr-polling'
                            , 'xhr-streaming'
                            , 'iframe-eventsource'
                            , 'iframe-htmlfile'
                            , 'xhr-polling'
                            , 'websocket'
                            ]
                      }
                    );

/**
* ## Data interaction hooks
*
* Passes off core SockJS data interaction hooks to rest of application so
* callbacks can be cleanly defined externally for each event.
*/
                socket.onopen = function(){
                    var args = arguments;
                    service.open = true;
                    service.timesOpened++;
                    // Attempted to connect. Note timestamp.
                    connectTimeStamps.push( new Date().getTime() );

                    $rootScope.$broadcast( 'SOCKET_CLOSED' );

                    if( service.handlers.onopen ){
                        $rootScope.$apply
                            ( function(){
                                service.handlers.onopen.apply( socket, args )
                              }
                            )
                    }
                }

                socket.onmessage = function( data ){
                    var args = arguments;
                    try{
                        args[0].data = JSON.parse(args[0].data);
                    } catch(e){
                        // there should be a better way to do this
                        // but it is fast
                    }

                    if( service.handlers.onmessage ){
                        $rootScope.$apply(
                            function(){
                                service.handlers.onmessage.apply(socket, args);
                            }
                        )
                    }
                }

                socket.onclose = function(){
                    service.open = false;
                    setTimeout( function(){ socket = createSocket(service); } , 3000 );
                    var args = arguments;
                    $rootScope.$broadcast( 'SOCKET_OPEN' );

                    if( service.handlers.onclose ){
                        $rootScope.$apply(
                            function(){
                                service.handlers.onclose.apply(socket,args);
                            }
                        )
                    }
                }

                return socket;
            }

            var service =
                { handlers : {}
                , onopen:
                    function( callback ){
                        this.handlers.onopen = callback;
                    }
                , onmessage:
                    function( callback ){
                        this.handlers.onmessage = callback;
                    }
                , onclose:
                    function( callback ){
                        this.handlers.onclose = callback;
                    }
                , send:
                    function( data ){
                        var msg = typeof(data) == "object" ? JSON.stringify(data) : data;
                        var status = socket.send(msg);
                    }
                , open: false
                };

            var socket = createSocket();
            return service;
        }
    ]
);