(PowerBuilder) Read Bitfinex WebSocket Ticker Channel

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

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

integer li_rc
oleobject loo_Ws
oleobject loo_Rest
integer li_Success
string ls_ResponseBody
oleobject loo_Json
integer li_FinalFrame
integer li_ReceivedFinalFrame
integer li_NumUpdatesReceived
string ls_ReceivedText

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

loo_Ws = create oleobject
// Use "Chilkat_9_5_0.WebSocket" for versions of Chilkat < 10.0.0
li_rc = loo_Ws.ConnectToNewObject("Chilkat.WebSocket")
if li_rc < 0 then
    destroy loo_Ws
    MessageBox("Error","Connecting to COM object failed")
    return
end if

// 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.

loo_Rest = create oleobject
// Use "Chilkat_9_5_0.Rest" for versions of Chilkat < 10.0.0
li_rc = loo_Rest.ConnectToNewObject("Chilkat.Rest")

// Connect to api.bitfinex.com
li_Success = loo_Rest.Connect("api.bitfinex.com",443,1,0)
loo_Ws.UseConnection(loo_Rest)
loo_Ws.AddClientHeaders()

ls_ResponseBody = loo_Rest.FullRequestNoBody("GET","/ws")
li_Success = loo_Ws.ValidateServerHandshake()
if li_Success <> 1 then
    Write-Debug loo_Ws.LastErrorText
    Write-Debug ls_ResponseBody
    Write-Debug loo_Rest.ResponseHeader
    destroy loo_Ws
    destroy loo_Rest
    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..
li_Success = loo_Ws.ReadFrame()
if li_Success <> 1 then
    Write-Debug "Failed to receive a frame"
    Write-Debug "ReadFrame fail reason = " + string(loo_Ws.ReadFrameFailReason)
    Write-Debug loo_Ws.LastErrorText
    destroy loo_Ws
    destroy loo_Rest
    return
end if

// We should get this:
// {"event":"info","version":1.1,"platform":{"status":1}}
Write-Debug loo_Ws.GetFrameData()

// Subscribe to the public ticker feed.
// See https://docs.bitfinex.com/docs for more information.
loo_Json = create oleobject
// Use "Chilkat_9_5_0.JsonObject" for versions of Chilkat < 10.0.0
li_rc = loo_Json.ConnectToNewObject("Chilkat.JsonObject")

loo_Json.AppendString("event","subscribe")
loo_Json.AppendString("channel","ticker")
loo_Json.AppendString("pair","BTCUSD")

li_FinalFrame = 1
li_Success = loo_Ws.SendFrame(loo_Json.Emit(),li_FinalFrame)

// Read the response.
li_Success = loo_Ws.ReadFrame()
if li_Success <> 1 then
    Write-Debug "Failed to receive a frame"
    Write-Debug "ReadFrame fail reason = " + string(loo_Ws.ReadFrameFailReason)
    Write-Debug loo_Ws.LastErrorText
    destroy loo_Ws
    destroy loo_Rest
    destroy loo_Json
    return
end if

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

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

    li_Success = loo_Ws.ReadFrame()
    if li_Success <> 1 then
        Write-Debug "Failed to receive a frame"
        Write-Debug "ReadFrame fail reason = " + string(loo_Ws.ReadFrameFailReason)
        Write-Debug loo_Ws.LastErrorText
        destroy loo_Ws
        destroy loo_Rest
        destroy loo_Json
        return
    end if

    // The responses we desire are in Text frames, where the opcode = 1.
    if loo_Ws.FrameOpcodeInt = 1 then
        ls_ReceivedText = loo_Ws.GetFrameData()
        Write-Debug ls_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]
        li_NumUpdatesReceived = li_NumUpdatesReceived + 1
    end if

loop

// Close the websocket connection.
li_Success = loo_Ws.SendClose(1,1000,"Closing this websocket.")
if li_Success <> 1 then
    Write-Debug loo_Ws.LastErrorText
    destroy loo_Ws
    destroy loo_Rest
    destroy loo_Json
    return
end if

// Read the Close response.
li_Success = loo_Ws.ReadFrame()
if li_Success <> 1 then
    Write-Debug "ReadFrame fail reason = " + string(loo_Ws.ReadFrameFailReason)
    Write-Debug loo_Ws.LastErrorText
    destroy loo_Ws
    destroy loo_Rest
    destroy loo_Json
    return
end if

Write-Debug "Success."


destroy loo_Ws
destroy loo_Rest
destroy loo_Json