(Objective-C) Get Size of File on Web Server

Demonstrates how to send a HEAD request to fetch information about a file on a web server, which hopefully includes the Content-Length in the response header.

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

// 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 = [http GetHead: @"https://nodejs.org/dist/v10.16.1/node-v10.16.1-win-x64.zip"];
if (http.LastMethodSuccess == NO) {
    NSLog(@"%@",http.LastErrorText);
    return;
}

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

// Here is a sample response header:

// Date: Thu, 01 Aug 2019 12:47:27 GMT
// Content-Type: application/zip
// Content-Length: 17457922
// Connection: keep-alive
// Set-Cookie: __cfduid=da5b78dcdd8171683c5a578eb9c9f88c81564663647; expires=Fri, 31-Jul-20 12:47:27 GMT; path=/; domain=.nodejs.org; HttpOnly
// Last-Modified: Wed, 31 Jul 2019 18:21:57 GMT
// ETag: "5d41dc45-10a6302"
// Accept-Ranges: bytes
// Expect-CT: max-age=604800, report-uri="https://report-uri.cloudflare.com/cdn-cgi/beacon/expect-ct"
// Server: cloudflare
// CF-RAY: 4ff7ebb32ac4e1e2-ORD

// Get the Content-Length header.
NSString *contentLengthStr = [resp GetHeaderField: @"Content-Length"];
// If the header exists...
if (resp.LastMethodSuccess == YES) {
    NSLog(@"%@%@",@"Content-Length: ",contentLengthStr);
    // Your application can convert the contentLengthStr to an integer and then use it....
}