(C) Send and Receive WebSocket Messages

This example how to send and receive websocket messages.

A WebSocket message can be composed of one or more frames. The simple case is where a single frame is both the first and last frame in a message. This is the case where the 1st frame in the message has the "final frame" bit set.

This example demonstrates sending and receiving multi-frame messages.

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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#include <C_CkWebSocket.h>
#include <C_CkRest.h>

void ChilkatSample(void)
    {
    HCkWebSocket ws;
    HCkRest rest;
    BOOL success;
    const char *responseBodyIgnored;
    BOOL finalFrame;
    BOOL receivedFinalFrame;
    const char *receivedMsg;

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

    ws = CkWebSocket_Create();

    // 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 = CkRest_Create();
    // 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 = CkRest_Connect(rest,"websockets.chilkat.io",80,FALSE,FALSE);
    CkWebSocket_UseConnection(ws,rest);
    CkWebSocket_AddClientHeaders(ws);
    responseBodyIgnored = CkRest_fullRequestNoBody(rest,"GET","/wsChilkatEcho.ashx");
    success = CkWebSocket_ValidateServerHandshake(ws);
    if (success != TRUE) {
        printf("%s\n",CkWebSocket_lastErrorText(ws));
        CkWebSocket_Dispose(ws);
        CkRest_Dispose(rest);
        return;
    }

    // This example demonstrates sending and receiving a multi-frame message.

    // The websocket message will be composed of three text lines, each frame will contain a single line.

    // Send the 1st frame in the message.
    finalFrame = FALSE;
    success = CkWebSocket_SendFrame(ws,"This is the 1st frame\r\n",finalFrame);
    if (success != TRUE) {
        printf("%s\n",CkWebSocket_lastErrorText(ws));
        CkWebSocket_Dispose(ws);
        CkRest_Dispose(rest);
        return;
    }

    // Send the 2nd frame in the message.
    success = CkWebSocket_SendFrame(ws,"This is the 2nd frame\r\n",finalFrame);
    if (success != TRUE) {
        printf("%s\n",CkWebSocket_lastErrorText(ws));
        CkWebSocket_Dispose(ws);
        CkRest_Dispose(rest);
        return;
    }

    // Send the 3rd and final frame in the message.
    finalFrame = TRUE;
    success = CkWebSocket_SendFrame(ws,"This is the 3rd frame\r\n",finalFrame);
    if (success != TRUE) {
        printf("%s\n",CkWebSocket_lastErrorText(ws));
        CkWebSocket_Dispose(ws);
        CkRest_Dispose(rest);
        return;
    }

    // Read an incoming frames until we receive the final frame.
    // Note: It may be that the echo server (websockets.chilkat.io) responds with 
    // the full message in a single final frame.
    receivedFinalFrame = FALSE;
    while (receivedFinalFrame == FALSE) {

        success = CkWebSocket_ReadFrame(ws);
        if (success != TRUE) {
            printf("Failed to receive a frame\n");
            printf("ReadFrame fail reason = %d\n",CkWebSocket_getReadFrameFailReason(ws));
            printf("%s\n",CkWebSocket_lastErrorText(ws));
            CkWebSocket_Dispose(ws);
            CkRest_Dispose(rest);
            return;
        }

        receivedFinalFrame = CkWebSocket_getFinalFrame(ws);

        // Show the opcode and final frame bit for the frame just received:
        printf("Frame opcode: %s\n",CkWebSocket_frameOpcode(ws));
        printf("Final frame: %d\n",receivedFinalFrame);
    }

    // Return the message accumulated in the above calls to ReadFrame.
    receivedMsg = CkWebSocket_getFrameData(ws);
    printf("Received: %s\n",receivedMsg);

    // Close the websocket connection.
    success = CkWebSocket_SendClose(ws,TRUE,1000,"Closing this websocket.");
    if (success != TRUE) {
        printf("%s\n",CkWebSocket_lastErrorText(ws));
        CkWebSocket_Dispose(ws);
        CkRest_Dispose(rest);
        return;
    }

    // Read the Close response.
    success = CkWebSocket_ReadFrame(ws);
    if (success != TRUE) {
        printf("ReadFrame fail reason = %d\n",CkWebSocket_getReadFrameFailReason(ws));
        printf("%s\n",CkWebSocket_lastErrorText(ws));
        CkWebSocket_Dispose(ws);
        CkRest_Dispose(rest);
        return;
    }

    // Should receive the "Close" opcode.
    printf("Received opcode: %s\n",CkWebSocket_frameOpcode(ws));
    // Should be the same status code we sent (1000)
    printf("Received close status code: %d\n",CkWebSocket_getCloseStatusCode(ws));
    // The server may echo the close reason.  If not, this will be empty.
    printf("Echoed close reason: %s\n",CkWebSocket_closeReason(ws));

    printf("Success.\n");


    CkWebSocket_Dispose(ws);
    CkRest_Dispose(rest);

    }