Swift

WebSocket Send/Receive Binary Data

See more WebSocket Examples

Demonstrates how to send and receive binary data on a websocket. This example uses Chilkat's websocket test echo server at ws://websockets.chilkat.io/wsChilkatEcho.ashx

Note: The websockets.chilkat.io server imposes the following limitations:
Messages must be 16K or less, and each connection is limited to a max of 16 echoed messages.

Swift

func chilkatTest() {
    var success: Bool = false

    // 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 websockets.chilkat.io
    // IMPORTANT: websockets.chilkat.io accepts frames of up to 16K in size and echoes them back.
    // IMPORTANT: The websockets.chilkat.io server imposes the following limitations: 
    // ---------- Messages must be 16K or less, and each connection is limited to a max of 16 echoed messages.
    success = rest.connect(hostname: "websockets.chilkat.io", port: 80, tls: false, autoReconnect: false)
    ws.useConnection(connection: rest)
    ws.addClientHeaders()
    var responseBodyIgnored: String? = rest.fullRequestNoBody(httpVerb: "GET", uriPath: "/wsChilkatEcho.ashx")
    success = ws.validateServerHandshake()
    if success != true {
        print("\(ws.lastErrorText!)")
        return
    }

    // This example sends a small JPG file (about 7KB) in a websocket frame.
    let jpgData = CkoBinData()!
    success = jpgData.loadFile(path: "qa_data/jpg/starfish.jpg")

    print("Number of bytes to send = \(jpgData.numBytes.intValue)")

    // Send a frame containing the JPG image data.
    // This will be the first and final frame, and therefore this constitutes the entire message.
    var finalFrame: Bool = true
    success = ws.sendFrameBd(bdToSend: jpgData, finalFrame: finalFrame)
    if success != true {
        print("\(ws.lastErrorText!)")
        return
    }

    // Read the echoed binary frame(s).
    // (We sent the JPG file in a single frame, but we may receive the echo in multiple frames, but it will be one message.)
    // Read an incoming frames until we receive the final frame.
    var receivedFinalFrame: Bool = false
    while receivedFinalFrame == false {

        // The ws object is accumulating the received data internally.  Once we get the final frame, we'll get the 
        // accumulated data which should constitute the entire JPG.
        success = ws.readFrame()
        if success != true {
            print("Failed to receive a frame")
            print("ReadFrame fail reason = \(ws.readFrameFailReason.intValue)")
            print("\(ws.lastErrorText!)")
            return
        }

        receivedFinalFrame = ws.finalFrame

        // Show the opcode and final frame bit for the frame just received:
        print("Frame opcode: \(ws.frameOpcode!)")
        print("Final frame: \(receivedFinalFrame)")
    }

    // Get the accumulated received data.
    let jpgReceivedData = CkoBinData()!
    ws.getFrameDataBd(binData: jpgReceivedData)
    print("Received \(jpgReceivedData.numBytes.intValue) bytes")

    // Save the received JPG to a file so we can check it..
    jpgReceivedData.writeFile(path: "qa_output/starfish_ws.jpg")

    // Close the websocket connection.
    success = ws.sendClose(includeStatus: 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
    }

    // Should receive the "Close" opcode.
    print("Received opcode: \(ws.frameOpcode!)")
    // Should be the same status code we sent (1000)
    print("Received close status code: \(ws.closeStatusCode.intValue)")
    // The server may echo the close reason.  If not, this will be empty.
    print("Echoed close reason: \(ws.closeReason!)")

    print("Success.")

}