(PureBasic) Send and Receive WebSocket Frame

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.

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IncludeFile "CkWebSocket.pb"
IncludeFile "CkRest.pb"

Procedure ChilkatExample()

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

    ws.i = CkWebSocket::ckCreate()
    If ws.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ; 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.

    rest.i = CkRest::ckCreate()
    If rest.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ; 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.i = CkRest::ckConnect(rest,"websockets.chilkat.io",80,0,0)
    CkWebSocket::ckUseConnection(ws,rest)
    CkWebSocket::ckAddClientHeaders(ws)
    responseBodyIgnored.s = CkRest::ckFullRequestNoBody(rest,"GET","/wsChilkatEcho.ashx")
    success = CkWebSocket::ckValidateServerHandshake(ws)
    If success <> 1
        Debug CkWebSocket::ckLastErrorText(ws)
        CkWebSocket::ckDispose(ws)
        CkRest::ckDispose(rest)
        ProcedureReturn
    EndIf

    ; 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.
    finalFrame.i = 1
    success = CkWebSocket::ckSendFrame(ws,"Hello World!",finalFrame)
    If success <> 1
        Debug CkWebSocket::ckLastErrorText(ws)
        CkWebSocket::ckDispose(ws)
        CkRest::ckDispose(rest)
        ProcedureReturn
    EndIf

    ; Read an incoming frame.
    success = CkWebSocket::ckReadFrame(ws)
    If success <> 1
        Debug "Failed to receive a frame"
        Debug "ReadFrame fail reason = " + Str(CkWebSocket::ckReadFrameFailReason(ws))
        Debug CkWebSocket::ckLastErrorText(ws)
        CkWebSocket::ckDispose(ws)
        CkRest::ckDispose(rest)
        ProcedureReturn
    EndIf

    ; Show the string that was received.
    receivedStr.s = CkWebSocket::ckGetFrameData(ws)
    Debug "Received: " + receivedStr

    ; Close the websocket connection.
    success = CkWebSocket::ckSendClose(ws,1,1000,"Closing this websocket.")
    If success <> 1
        Debug CkWebSocket::ckLastErrorText(ws)
        CkWebSocket::ckDispose(ws)
        CkRest::ckDispose(rest)
        ProcedureReturn
    EndIf

    ; Read the Close response.
    success = CkWebSocket::ckReadFrame(ws)
    If success <> 1
        Debug "ReadFrame fail reason = " + Str(CkWebSocket::ckReadFrameFailReason(ws))
        Debug CkWebSocket::ckLastErrorText(ws)
        CkWebSocket::ckDispose(ws)
        CkRest::ckDispose(rest)
        ProcedureReturn
    EndIf

    ; Should receive the "Close" opcode.
    Debug "Received opcode: " + CkWebSocket::ckFrameOpcode(ws)
    ; Should be the same status code we sent (1000)
    Debug "Received close status code: " + Str(CkWebSocket::ckCloseStatusCode(ws))
    ; The server may echo the close reason.  If not, this will be empty.
    Debug "Echoed close reason: " + CkWebSocket::ckCloseReason(ws)

    Debug "Success."


    CkWebSocket::ckDispose(ws)
    CkRest::ckDispose(rest)


    ProcedureReturn
EndProcedure