A meditation on angular websocket services in coffescript.

gistfile1.coffee

myModule.factory 'websocket', ($q) ->
#   to run, inject thus:
#   myModule.run (websocket) ->
#     websocket.connect("ws://localhost:8000")

#     websocket.on "myCommand", (data) ->
#         c.log "data received!", data

#     websocket.send "my outgoing message"

    def = $q.defer()
    command_map = {}
    ws = null

    connect : (url) ->
        ws = new WebSocket(url)

        ws.onmessage = (evt) ->
            data = JSON.parse evt.data
            {command} = data
            for listener in command_map[command]
                listener(data)

        ws.onopen = (evt) ->
            def.resolve(evt)

        ws.onerror = (evt) ->
            def.reject(evt)

    send: (msg) ->
        def.promise.then () ->
            ws.send(msg)

    close : () ->
        def.promise.then () ->
            ws.close()

    on : (command_str, callback) ->
        unless command_str in command_map
            command_map[command_str] = []
        command_map[command_str].push callback

    off : (command_str, callback) ->
        command_map[command_str]?.splice command_map.indexOf(command_str), 1