(MFC) Manually Follow HTTP Redirects

Demonstrates how to manually follow redirects for an HTTP GET.

Chilkat C/C++ Library Downloads MS Visual C/C++ Libs

See Also: Using MFC CString in Chilkat

#include <CkHttp.h>
#include <CkHttpResponse.h>

void ChilkatSample(void)
    {
    CkString strOut;

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

    CkHttp http;

    // The FollowRedirects property controls whether redirects
    // are automatically followed.  The default behavior is to
    // automatically follow redirects.

    // Explicitly set FollowRedirects so that redirects are NOT automatically taken:
    http.put_FollowRedirects(false);

    CkHttpResponse *resp = http.QuickGetObj("http://yandex.ru/");
    if (http.get_LastMethodSuccess() == false) {
        strOut.append(http.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    int status = resp->get_StatusCode();
    strOut.append("HTTP Response Status: ");
    strOut.appendInt(status);
    strOut.append("\r\n");

    // The FinalRedirectUrl property will contain the redirect URL
    // If FollowRedirects was equal to true, then all of the 
    // intermediate redirects (if any) would be followed until
    // there were no more redirects.  However, because 
    // FollowRedirects is not true, FinalRedirectUrl contains
    // the next redirect URL.

    int loopCount = 0;

    while ((status == 302)) {

        // IMPORTANT: This example requires Chilkat v9.5.0.49 or greater because
        // the FinalRedirectUrl in prior versions is only set when redirects
        // are automatically followed.   Starting in v9.5.0.49, the FinalRedirectUrl is
        // set to the next redirect URL when a 301/302 response is received, regardless
        // of the value of the FollowRedirects property.
        strOut.append("Redirect URL: ");
        strOut.append(http.finalRedirectUrl());
        strOut.append("\r\n");

        delete resp;

        const char *nextUrl = http.finalRedirectUrl();
        resp = http.QuickGetObj(nextUrl);
        if (http.get_LastMethodSuccess() == false) {
            strOut.append(http.lastErrorText());
            strOut.append("\r\n");
            SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
            return;
        }

        status = resp->get_StatusCode();
        strOut.append("HTTP Response Status: ");
        strOut.appendInt(status);
        strOut.append("\r\n");

        // For safety, prevent infinite loops by
        // keeping a loopCount and only allows following a max 
        // of 10 redirects:
        loopCount = loopCount + 1;
        if (loopCount > 10) {
            delete resp;
            strOut.append("Too many redirects.");
            strOut.append("\r\n");
            SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
            return;
        }

        delete resp;

    }



    SetDlgItemText(IDC_EDIT1,strOut.getUnicode());

    }