C

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.

C

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

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

    success = FALSE;

    // 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 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 = TRUE;
    success = CkWebSocket_SendFrame(ws,"Hello World!",finalFrame);
    if (success != TRUE) {
        printf("%s\n",CkWebSocket_lastErrorText(ws));
        CkWebSocket_Dispose(ws);
        CkRest_Dispose(rest);
        return;
    }

    // Read an incoming frame.
    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;
    }

    // Show the string that was received.
    receivedStr = CkWebSocket_getFrameData(ws);
    printf("Received: %s\n",receivedStr);

    // 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);

    }