C++

Cancel HTTP Get Async Task if not Completed after a Max Time

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Demonstrates how to wait a maximum amount of time for an asynchronous task to completed. If not completed in the allotted amount of time, the task is cancelled. C++

#include <CkHttp.h>
#include <CkTask.h>

void ChilkatSample(void)
    {
    bool success = false;

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

    CkHttp http;

    // Set some timeouts, in seconds:
    http.put_ConnectTimeout(15);
    // ReadTimeout specifies the max number of seconds that must elapse when no additional data is received before
    // timing out.  For example, if a server sends a 300 byte response at the rate of 1 byte per second, then
    // ReadTimeout would never cause a timeout because there is never a 15 second interval when nothing arrives.
    http.put_ReadTimeout(15);

    const char *url = "https://your-url.com/something";
    CkTask *task = http.QuickGetStrAsync(url);
    task->Run();

    // Wait a maximum of waitMaxMs for the task (i.e. the HTTP GET) to complete.
    // The Wait method returns when the task has been canceled, aborted, or completed, or when the max allotted time has passed.
    int waitMaxMs = 20000;
    task->Wait(waitMaxMs);

    // At this point, the GET may or may not have completed.  
    // Rather than checking the Task status, we can call task.Cancel because
    // if the Task is no longer running (because it already completed, was canceled or aborted), then the 
    // call to Cancel is a NO-OP (meaning it does nothing and the Task's status is unaffected).
    // Also, task.Cancel returns true if the task was in the "queued" or "running" state and was canceled or aborted. 
    // The method returns false if the task has any other status.
    bool wasCanceled = task->Cancel();
    if (wasCanceled == true) {
        std::cout << "The HTTP GET took too long and was canceled." << "\r\n";
    }
    else {
        // Find out what happened.
        if (task->get_StatusInt() == 7) {
            // The task completed, which means the background thread's call to QuickGetStr completed
            // with success or failure.  Find out which...
            if (task->get_TaskSuccess() == true) {
                // Get the string response for the call to QuickGetStr (which happened in Chilkat's background thread).
                const char *responseStr = task->getResultString();
                std::cout << responseStr << "\r\n";
                std::cout << "HTTP GET successful!" << "\r\n";
            }
            else {
                std::cout << "HTTP GET failed prior to waitMaxMs..." << "\r\n";
                std::cout << task->resultErrorText() << "\r\n";
            }

        }
        else {
            // The task must've been canceled or aborted by some other means..
            std::cout << "Task did not complete.  Final status: " << task->status() << "\r\n";
        }

    }

    delete task;
    }