B4R Library WebSocketClient

rWebSocketClient library is a WebSocket client implementation. It is based on this open source project: https://github.com/brandenhall/Arduino-Websocket

The library is similar to B4X WebSocketHandler class: https://www.b4x.com/android/forum/threads/websocket-client-library.40221/#content
This means that it is intended to be used with B4J WebSocket servers.

Using it is simple:
1. Create a client object such as EthernetSocket.
2. Call Connect to connect to the server:

websocket.ConnectIp(ethClient.Stream, serverIp, serverPort, path)

3. Send events to the server with SendEventToServer:

websocket.SendEventToServer("Btn_StateChanged", Array As String("btn", 0, "state", Not(State)))

This will cause the Btn_StateChanged sub on the server to be raised:

'b4j
Sub Btn_StateChanged (Params As Map)
   Dim id As String = "arduino_btn" & Params.Get("btn")
   Dim state As Boolean = Params.Get("state")
   For Each br As Browser In Main.ConnectedBrowsers.Keys
     CallSubDelayed3(br, "UpdateButton", id, state)
   Next
End Sub

4. The server can send events to the client:

'Must be an array of strings and the parameters cannot include quotes.
ws.RunFunction("Led", Array As String(LedId.SubString("arduino_led".Length), State))
ws.Flush

This will cause the WebSocket_NewMessage event to be raised on the Arduino:

Sub WebSocket_NewMessage (FunctionName As String, Params() As String)
   Select FunctionName
     Case "ServerTime"
       Log("Server time: ", Params(0))
     Case "Led"
       leds(Params(0)).DigitalWrite(Params(1) = "true")
   End Select
End Sub

So now it is easy to control the Arduino from the browser!

The connections diagram for this example:

The projects and library are attached. The B4R project requires B4R v1.00 beta 8+.

 

[Beja]

I must give this a big Like.. thanks Erel
My experience with websockets is limited in devices on the same network, therefore I wish there is a tutorial on how to
control an Arduino over the WWW without having a personal web server.

 

[Erel]

Exactly the same code is used when connecting to a local server or over the internet.

Connecting to a local pc over the internet requires some configuration as explained here: https://www.b4x.com/android/forum/t...r-b4j-server-over-the-internet.37201/#content

For further discussion please start a new thread in the B4J forum.

 

[giga]

Nice work Erel, I haven't tried B4R yet but this looks great!!

 

[MathiasM]

This might be a stupid question, but is rWebsocketClient able to connect to a Secure Websocket?
Thanks

 

[Erel]

I haven't tested it, however if you are using ESP8266 then you can pass a WiFiSSLSocket. Try it.