PowerBuilder

Subscribe to Multiple Bitfinex Tickers on One Connection

See more WebSocket Examples

Subscribes to multiple ticker symbols on the public Bitfinex websocket ticker channel and receives ticker updates. PowerBuilder

integer li_rc
integer li_Success
oleobject loo_Ws
oleobject loo_Rest
string ls_ResponseBody
oleobject loo_Json1
integer li_FinalFrame
oleobject loo_Json2
integer li_ReceivedFinalFrame
integer li_NumUpdatesReceived
string ls_ReceivedText

li_Success = 0

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

loo_Ws = create oleobject
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
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 BTCUSD ticker feed.
// See https://docs.bitfinex.com/docs for more information.
loo_Json1 = create oleobject
li_rc = loo_Json1.ConnectToNewObject("Chilkat.JsonObject")

loo_Json1.AppendString("event","subscribe")
loo_Json1.AppendString("channel","ticker")
loo_Json1.AppendString("pair","BTCUSD")

li_FinalFrame = 1
li_Success = loo_Ws.SendFrame(loo_Json1.Emit(),li_FinalFrame)

// Subscribe to the ETHUSD ticker feed.
loo_Json2 = create oleobject
li_rc = loo_Json2.ConnectToNewObject("Chilkat.JsonObject")

loo_Json2.AppendString("event","subscribe")
loo_Json2.AppendString("channel","ticker")
loo_Json2.AppendString("pair","ETHUSD")

li_Success = loo_Ws.SendFrame(loo_Json2.Emit(),li_FinalFrame)

// Begin reading the ticker feed.
// / This will include a single confirmation response for each subscription.

// We'll just read the 1st 5 updates and then exit..
li_ReceivedFinalFrame = 0
li_NumUpdatesReceived = 0
do while li_NumUpdatesReceived < 7

    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_Json1
        destroy loo_Json2
        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]
        // Initially, a single confirmation response for each subscription would be received, such as this:
        // {"event":"subscribed","channel":"ticker","chanId":810,"pair":"BTCUSD"}
        li_NumUpdatesReceived = li_NumUpdatesReceived + 1
    end if

loop

// This is sample output:
// You can see that the 1st message received is the subscription confirmation for the BTCUSD subscribe request.
// The next message is a BTCUSD ticker update.
// The next message is the confirmation for the ETHUSD subscription.
// The next message is an ETHUSD update.
// The BTCUSD channel ID is "537", and the ETHUSD channel ID is "700".  The channel IDs are provided in the 
// subscription confirmation messages.  Each ticker update begins with the channel ID..

// {"event":"subscribed","channel":"ticker","chanId":537,"pair":"BTCUSD"}
// [537,6457.9,79.59102302,6458,22.49395741,-24.1,-0.0037,6457.9,13644.52820029,6540,6370.76958739]
// {"event":"subscribed","channel":"ticker","chanId":700,"pair":"ETHUSD"}
// [700,496.9,247.24493326,496.92,284.09636979,-2.47,-0.0049,496.9,74154.05945261,502.85,486.96]
// [537,"hb"]
// [700,"hb"]
// [700,496.92,233.34338276,496.93,431.78867277,-2.45,-0.0049,496.92,74167.99173586,502.85,486.96]

// 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_Json1
    destroy loo_Json2
    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_Json1
    destroy loo_Json2
    return
end if

Write-Debug "Success."


destroy loo_Ws
destroy loo_Rest
destroy loo_Json1
destroy loo_Json2