HTTP in a Background Thread (Asynchronous HTTP)

This example shows the technique one would follow to run any Chilkat HTTP method in a background task. (Only HTTP methods that communicate with an HTTP server are background-enabled. Methods that perform no HTTP communications return immediately and never need to be backgrounded.)

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#include <C_CkHttp.h>

void ChilkatSample(void)
    {
    HCkHttp http;
    BOOL success;
    long n;
    long i;

    http = CkHttp_Create();

    //  Any string unlocks the component for the 1st 30-days.
    success = CkHttp_UnlockComponent(http,"Anything for 30-day trial");
    if (success != TRUE) {
        printf("%s\n",CkHttp_lastErrorText(http));
        return;
    }

    //  To run an HTTP method asynchronously in a background thread, set
    //  the UseBgThread property equal to TRUE
    CkHttp_putUseBgThread(http,TRUE);

    //  For those programming languages that support event callbacks:
    //  events are not fired when a task is running in the background thread.
    //  Instead, Chilkat has added the "event log" mechanism.  While the
    //  background task is running, events that normally would've been fired
    //  are accumulated in the event log.  Your application may periodically check
    //  the event log to keep track of the progress of the background task.
    //  To enable event logging, set the KeepEventLog property = TRUE
    CkHttp_putKeepEventLog(http,TRUE);

    //  Start an asynchronous HTTP download in a background thread.
    //  The method will return cktrue if the task was successfully started.
    //  Note: When the UseBgThread property = TRUE, all methods involving
    //  HTTP communications will be asynchronous.  These methods include:
    //  SynchronousRequest, QuickGetStr, QuickGet, PostUrlEncoded, XmlRpc,
    //  XmlRpcPut, QuickPutStr, QuickGetObj, QuickDeleteStr, PutText,
    //  PutBinary, PostBinary, PostMime, GetHead, DownloadAppend, etc.
    success = CkHttp_Download(http,"http://www.chilkatsoft.com/download/ChilkatJava.zip","ChilkatJava.zip");
    if (success != TRUE) {
        printf("%s\n",CkHttp_lastErrorText(http));
        return;
    }
    else {
        printf("Initiated asynchronous HTTP download...\n");
    }

    //  Write a loop to wait for the background task to complete.
    //  Your application would typically do something different than this --
    //  after all... there's no point in doing the task asynchronously if your application
    //  is simply going to wait for it to complete -- that's the same as doing it synchronously,
    //  and that could've been achieved by a single call to the http.Download method
    //  with the UseBgThread = FALSE.
    //  However... we do this here for the purpose of demonstration...
    while ((CkHttp_getBgTaskRunning(http) == TRUE)) {
        //  Show the events in the event log that have accumulated so far...

        n = CkHttp_getEventLogCount(http);
        if (n > 0) {

            for (i = 0; i <= n - 1; i++) {
                printf("%s: %s\n",CkHttp_eventLogName(http,i)
                    ,CkHttp_eventLogValue(http,i));
            }

            CkHttp_ClearEventLog(http);
        }

        //  In some programming languages, you might wish to handle user-interface events
        //  For example, in C#  you might call Application.DoEvents()

        //  Sleep .1 seconds -- to keep the CPU from being 100% busy...
        CkHttp_SleepMs(http,100);
    }

    //  Once the background task has completed, check it for success/failure:
    if (CkHttp_getBgTaskSuccess(http)) {
        printf("Background task completed successfully.\n");
    }



    CkHttp_Dispose(http);

    }