(C++) Get the Last-Modified Date Before HTTP Download

Demonstrates how to send a HEAD request to get the last-modified date of a file on a web server (without downloading the file).

Note: This example requires Chilkat v11.0.0 or greater.

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

void ChilkatSample(void)
    {
    bool success = false;

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

    CkHttp http;

    CkHttpResponse resp;
    success = http.HttpNoBody("HEAD","https://www.chilkatsoft.com/hamlet.xml",resp);
    if (success == false) {
        std::cout << http.lastErrorText() << "\r\n";
        return;
    }

    // Examine the response header.
    std::cout << resp.header() << "\r\n";

    // Here is a sample response header:

    // 	Content-Length: 279658
    // 	Content-Type: text/xml
    // 	Last-Modified: Thu, 12 May 2016 15:14:08 GMT
    // 	Accept-Ranges: bytes
    // 	ETag: "c1cd8bee60acd11:0"
    // 	Server: Microsoft-IIS/8.5
    // 	X-Powered-By: ASP.NET
    // 	X-Powered-By-Plesk: PleskWin
    // 	Date: Thu, 25 Jul 2019 16:40:54 GMT

    // Get the Last-Modified header.
    const char *lastModStr = resp.getHeaderField("Last-Modified");
    // If the header exists...
    if (resp.get_LastMethodSuccess() == true) {
        // Parse the RFC822 format date/time string
        CkDateTime ckdt;
        ckdt.SetFromRfc822(lastModStr);

        // If we want to access individual date/time parts (in the local timezone)
        CkDtObj dt;
        ckdt.ToDtObj(true,dt);

        std::cout << "day/month/year = " << dt.get_Day() << "/" << dt.get_Month() << "/" << dt.get_Year() << "\r\n";
    }
    }