Xojo Plugin

Read Bitfinex WebSocket Ticker Channel

See more WebSocket Examples

Subscribes to the public Bitfinex websocket ticker channel and receives ticker updates. Xojo Plugin

Dim success As Boolean
success = False

// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

Dim ws As New Chilkat.WebSocket

// For brevity, this example does not check for errors when etablishing the WebSocket connection.
// See Establish WebSocket Connection for more complete sample code for making the connection.

Dim rest As New Chilkat.Rest

// Connect to api.bitfinex.com
success = rest.Connect("api.bitfinex.com",443,True,False)
success = ws.UseConnection(rest)
success = ws.AddClientHeaders()

Dim responseBody As String
responseBody = rest.FullRequestNoBody("GET","/ws")
success = ws.ValidateServerHandshake()
If (success <> True) Then
    System.DebugLog(ws.LastErrorText)
    System.DebugLog(responseBody)
    System.DebugLog(rest.ResponseHeader)
    Return
End If

// After connecting, the bitfinex websocket server will send
// an info message that contains the actual version of the websocket stream.
// Receive that message..
success = ws.ReadFrame()
If (success <> True) Then
    System.DebugLog("Failed to receive a frame")
    System.DebugLog("ReadFrame fail reason = " + Str(ws.ReadFrameFailReason))
    System.DebugLog(ws.LastErrorText)
    Return
End If

// We should get this:
// {"event":"info","version":1.1,"platform":{"status":1}}
System.DebugLog(ws.GetFrameData())

// Subscribe to the public ticker feed.
// See https://docs.bitfinex.com/docs for more information.
Dim json As New Chilkat.JsonObject
success = json.AppendString("event","subscribe")
success = json.AppendString("channel","ticker")
success = json.AppendString("pair","BTCUSD")

Dim finalFrame As Boolean
finalFrame = True
success = ws.SendFrame(json.Emit(),finalFrame)

// Read the response.
success = ws.ReadFrame()
If (success <> True) Then
    System.DebugLog("Failed to receive a frame")
    System.DebugLog("ReadFrame fail reason = " + Str(ws.ReadFrameFailReason))
    System.DebugLog(ws.LastErrorText)
    Return
End If

// Examine the response
// We should get this:
// {"event":"subscribed","channel":"ticker","chanId":2751,"pair":"BTCUSD"}
System.DebugLog(ws.GetFrameData())

// Begin reading the ticker feed.
// We'll just read the 1st 5 updates and then exit..
Dim receivedFinalFrame As Boolean
receivedFinalFrame = False
Dim numUpdatesReceived As Int32
numUpdatesReceived = 0
While numUpdatesReceived < 5

    success = ws.ReadFrame()
    If (success <> True) Then
        System.DebugLog("Failed to receive a frame")
        System.DebugLog("ReadFrame fail reason = " + Str(ws.ReadFrameFailReason))
        System.DebugLog(ws.LastErrorText)
        Return
    End If

    // The responses we desire are in Text frames, where the opcode = 1.
    If (ws.FrameOpcodeInt = 1) Then
        Dim receivedText As String
        receivedText = ws.GetFrameData()
        System.DebugLog(receivedText)
        // Should receive a line of text such as this:
        // [2751,7349,36.34269559,7349.1,41.01777063,-116.2,-0.0156,7349.1,22188.26055319,7560,7270.5]
        numUpdatesReceived = numUpdatesReceived + 1
    End If

Wend

// Close the websocket connection.
success = ws.SendClose(True,1000,"Closing this websocket.")
If (success <> True) Then
    System.DebugLog(ws.LastErrorText)
    Return
End If

// Read the Close response.
success = ws.ReadFrame()
If (success <> True) Then
    System.DebugLog("ReadFrame fail reason = " + Str(ws.ReadFrameFailReason))
    System.DebugLog(ws.LastErrorText)
    Return
End If

System.DebugLog("Success.")