Objective-C

Get the Last-Modified Date Before HTTP Download

See more HTTP Examples

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

#import <CkoHttp.h>
#import <CkoHttpResponse.h>
#import <NSString.h>
#import <CkoDateTime.h>
#import <CkoDtObj.h>

BOOL success = NO;

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

CkoHttp *http = [[CkoHttp alloc] init];

CkoHttpResponse *resp = [[CkoHttpResponse alloc] init];
success = [http HttpNoBody: @"HEAD" url: @"https://www.chilkatsoft.com/hamlet.xml" response: resp];
if (success == NO) {
    NSLog(@"%@",http.LastErrorText);
    return;
}

// Examine the response header.
NSLog(@"%@",resp.Header);

// 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.
NSString *lastModStr = [resp GetHeaderField: @"Last-Modified"];
// If the header exists...
if (resp.LastMethodSuccess == YES) {
    // Parse the RFC822 format date/time string
    CkoDateTime *ckdt = [[CkoDateTime alloc] init];
    [ckdt SetFromRfc822: lastModStr];

    // If we want to access individual date/time parts (in the local timezone)
    CkoDtObj *dt = [[CkoDtObj alloc] init];
    [ckdt ToDtObj: YES dtObj: dt];

    NSLog(@"%@%d%@%d%@%d",@"day/month/year = ",[dt.Day intValue],@"/",[dt.Month intValue],@"/",[dt.Year intValue]);
}