B4X

Read Bitfinex WebSocket Ticker Channel

See more WebSocket Examples

Subscribes to the public Bitfinex websocket ticker channel and receives ticker updates. B4X

Dim success As Boolean = False

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

Dim ws As ChilkatWebSocket
ws.Initialize("ws")

'  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 ChilkatRest
rest.Initialize("rest")

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

Dim responseBody As String = rest.FullRequestNoBody("GET", "/ws")
success = ws.ValidateServerHandshake
If success <> True Then
    Log(ws.LastErrorText)
    Log(responseBody)
    Log(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
    Log("Failed to receive a frame")
    Log("ReadFrame fail reason = " & ws.ReadFrameFailReason)
    Log(ws.LastErrorText)
    Return
End If


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

'  Subscribe to the public ticker feed.
'  See https://docs.bitfinex.com/docs for more information.
Dim json As ChilkatJsonObject
json.Initialize
json.AppendString("event", "subscribe")
json.AppendString("channel", "ticker")
json.AppendString("pair", "BTCUSD")

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

'  Read the response.
success = ws.ReadFrame
If success <> True Then
    Log("Failed to receive a frame")
    Log("ReadFrame fail reason = " & ws.ReadFrameFailReason)
    Log(ws.LastErrorText)
    Return
End If


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

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

    success = ws.ReadFrame
    If success <> True Then
        Log("Failed to receive a frame")
        Log("ReadFrame fail reason = " & ws.ReadFrameFailReason)
        Log(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 = ws.GetFrameData
        Log(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


Loop

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


'  Read the Close response.
success = ws.ReadFrame
If success <> True Then
    Log("ReadFrame fail reason = " & ws.ReadFrameFailReason)
    Log(ws.LastErrorText)
    Return
End If


Log("Success.")