DataFlex

Send and Receive WebSocket Frame

See more WebSocket Examples

Demonstrates how to send a websocket text frame to a websocket echo server. 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.

DataFlex

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Handle hoWs
    Variant vRest
    Handle hoRest
    String sResponseBodyIgnored
    Boolean iFinalFrame
    String sReceivedStr
    String sTemp1
    Integer iTemp1

    Move False To iSuccess

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

    Get Create (RefClass(cComChilkatWebSocket)) To hoWs
    If (Not(IsComObjectCreated(hoWs))) Begin
        Send CreateComObject of hoWs
    End

    // 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.

    Get Create (RefClass(cComChilkatRest)) To hoRest
    If (Not(IsComObjectCreated(hoRest))) Begin
        Send CreateComObject of hoRest
    End
    // 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.
    Get ComConnect Of hoRest "websockets.chilkat.io" 80 False False To iSuccess
    Get pvComObject of hoRest to vRest
    Get ComUseConnection Of hoWs vRest To iSuccess
    Get ComAddClientHeaders Of hoWs To iSuccess
    Get ComFullRequestNoBody Of hoRest "GET" "/wsChilkatEcho.ashx" To sResponseBodyIgnored
    Get ComValidateServerHandshake Of hoWs To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoWs To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // This example demonstrates sending a frame and receiving a text frame.

    // Send a frame containing the string "Hello World!"
    // This will be the first and final frame, and therefore this constitutes the entire message.
    Move True To iFinalFrame
    Get ComSendFrame Of hoWs "Hello World!" iFinalFrame To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoWs To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Read an incoming frame.
    Get ComReadFrame Of hoWs To iSuccess
    If (iSuccess <> True) Begin
        Showln "Failed to receive a frame"
        Get ComReadFrameFailReason Of hoWs To iTemp1
        Showln "ReadFrame fail reason = " iTemp1
        Get ComLastErrorText Of hoWs To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Show the string that was received.
    Get ComGetFrameData Of hoWs To sReceivedStr
    Showln "Received: " sReceivedStr

    // Close the websocket connection.
    Get ComSendClose Of hoWs True 1000 "Closing this websocket." To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoWs To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Read the Close response.
    Get ComReadFrame Of hoWs To iSuccess
    If (iSuccess <> True) Begin
        Get ComReadFrameFailReason Of hoWs To iTemp1
        Showln "ReadFrame fail reason = " iTemp1
        Get ComLastErrorText Of hoWs To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Should receive the "Close" opcode.
    Get ComFrameOpcode Of hoWs To sTemp1
    Showln "Received opcode: " sTemp1
    // Should be the same status code we sent (1000)
    Get ComCloseStatusCode Of hoWs To iTemp1
    Showln "Received close status code: " iTemp1
    // The server may echo the close reason.  If not, this will be empty.
    Get ComCloseReason Of hoWs To sTemp1
    Showln "Echoed close reason: " sTemp1

    Showln "Success."


End_Procedure