(Swift) Read Bitfinex WebSocket Ticker Channel

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

Chilkat Downloads for the Swift Programming Language MAC OS X (Cocoa) Objective-C/Swift Libs iOS Objective-C/Swift Libs

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

    let ws = CkoWebSocket()

    //  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.

    let rest = CkoRest()

    //  Connect to api.bitfinex.com
    var success: Bool = rest.Connect("api.bitfinex.com", port: 443, tls: true, autoReconnect: false)
    ws.UseConnection(rest)
    ws.AddClientHeaders()

    var responseBody: String? = rest.FullRequestNoBody("GET", uriPath: "/ws")
    success = ws.ValidateServerHandshake()
    if success != true {
        print("\(ws.LastErrorText)")
        print("\(responseBody!)")
        print("\(rest.ResponseHeader)")
        return
    }

    //  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 {
        print("Failed to receive a frame")
        print("ReadFrame fail reason = \(ws.ReadFrameFailReason.intValue)")
        print("\(ws.LastErrorText)")
        return
    }

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

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

    var finalFrame: Bool = true
    success = ws.SendFrame(json.Emit(), finalFrame: finalFrame)

    //  Read the response.
    success = ws.ReadFrame()
    if success != true {
        print("Failed to receive a frame")
        print("ReadFrame fail reason = \(ws.ReadFrameFailReason.intValue)")
        print("\(ws.LastErrorText)")
        return
    }

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

    //  Begin reading the ticker feed.
    //  We'll just read the 1st 5 updates and then exit..
    var receivedFinalFrame: Bool = false
    var numUpdatesReceived: Int = 0
    while numUpdatesReceived < 5 {

        success = ws.ReadFrame()
        if success != true {
            print("Failed to receive a frame")
            print("ReadFrame fail reason = \(ws.ReadFrameFailReason.intValue)")
            print("\(ws.LastErrorText)")
            return
        }

        //  The responses we desire are in Text frames, where the opcode = 1.
        if ws.FrameOpcodeInt.intValue == 1 {
            var receivedText: String? = ws.GetFrameData()
            print("\(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
        }

    }

    //  Close the websocket connection.
    success = ws.SendClose(true, statusCode: 1000, reason: "Closing this websocket.")
    if success != true {
        print("\(ws.LastErrorText)")
        return
    }

    //  Read the Close response.
    success = ws.ReadFrame()
    if success != true {
        print("ReadFrame fail reason = \(ws.ReadFrameFailReason.intValue)")
        print("\(ws.LastErrorText)")
        return
    }

    print("Success.")

}