(Swift 3,4,5...) Subscribe to Multiple Bitfinex Tickers on One Connection

Subscribes to multiple ticker symbols on 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 BTCUSD ticker feed.
    // See https://docs.bitfinex.com/docs for more information.
    let json1 = CkoJsonObject()!
    json1.append("event", value: "subscribe")
    json1.append("channel", value: "ticker")
    json1.append("pair", value: "BTCUSD")

    var finalFrame: Bool = true
    success = ws.sendFrame(json1.emit(), finalFrame: finalFrame)

    // Subscribe to the ETHUSD ticker feed.
    let json2 = CkoJsonObject()!
    json2.append("event", value: "subscribe")
    json2.append("channel", value: "ticker")
    json2.append("pair", value: "ETHUSD")

    success = ws.sendFrame(json2.emit(), finalFrame: 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..
    var receivedFinalFrame: Bool = false
    var numUpdatesReceived: Int = 0
    while numUpdatesReceived < 7 {

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

    }

    // 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.
    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.")

}