(Lianja) Read Bitfinex WebSocket Ticker Channel

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

Chilkat Lianja Extension Download Chilkat Lianja Extension

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

loWs = createobject("CkWebSocket")

//  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.

loRest = createobject("CkRest")

//  Connect to api.bitfinex.com
llSuccess = loRest.Connect("api.bitfinex.com",443,.T.,.F.)
loWs.UseConnection(loRest)
loWs.AddClientHeaders()

lcResponseBody = loRest.FullRequestNoBody("GET","/ws")
llSuccess = loWs.ValidateServerHandshake()
if (llSuccess <> .T.) then
    ? loWs.LastErrorText
    ? lcResponseBody
    ? loRest.ResponseHeader
    release loWs
    release loRest
    return
endif

//  After connecting, the bitfinex websocket server will send
//  an info message that contains the actual version of the websocket stream.
//  Receive that message..
llSuccess = loWs.ReadFrame()
if (llSuccess <> .T.) then
    ? "Failed to receive a frame"
    ? "ReadFrame fail reason = " + str(loWs.ReadFrameFailReason)
    ? loWs.LastErrorText
    release loWs
    release loRest
    return
endif

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

//  Subscribe to the public ticker feed.
//  See https://docs.bitfinex.com/docs for more information.
loJson = createobject("CkJsonObject")
loJson.AppendString("event","subscribe")
loJson.AppendString("channel","ticker")
loJson.AppendString("pair","BTCUSD")

llFinalFrame = .T.
llSuccess = loWs.SendFrame(loJson.Emit(),llFinalFrame)

//  Read the response.
llSuccess = loWs.ReadFrame()
if (llSuccess <> .T.) then
    ? "Failed to receive a frame"
    ? "ReadFrame fail reason = " + str(loWs.ReadFrameFailReason)
    ? loWs.LastErrorText
    release loWs
    release loRest
    release loJson
    return
endif

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

//  Begin reading the ticker feed.
//  We'll just read the 1st 5 updates and then exit..
llReceivedFinalFrame = .F.
lnNumUpdatesReceived = 0
do while lnNumUpdatesReceived < 5

    llSuccess = loWs.ReadFrame()
    if (llSuccess <> .T.) then
        ? "Failed to receive a frame"
        ? "ReadFrame fail reason = " + str(loWs.ReadFrameFailReason)
        ? loWs.LastErrorText
        release loWs
        release loRest
        release loJson
        return
    endif

    //  The responses we desire are in Text frames, where the opcode = 1.
    if (loWs.FrameOpcodeInt = 1) then
        lcReceivedText = loWs.GetFrameData()
        ? lcReceivedText
        //  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]
        lnNumUpdatesReceived = lnNumUpdatesReceived + 1
    endif

enddo

//  Close the websocket connection.
llSuccess = loWs.SendClose(.T.,1000,"Closing this websocket.")
if (llSuccess <> .T.) then
    ? loWs.LastErrorText
    release loWs
    release loRest
    release loJson
    return
endif

//  Read the Close response.
llSuccess = loWs.ReadFrame()
if (llSuccess <> .T.) then
    ? "ReadFrame fail reason = " + str(loWs.ReadFrameFailReason)
    ? loWs.LastErrorText
    release loWs
    release loRest
    release loJson
    return
endif

? "Success."


release loWs
release loRest
release loJson