Check File Size using HEAD Request

Demonstrates how to quickly check the size of an HTTP download by using the HEAD request.

Download Chilkat HTTP ActiveX

uses
    Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
    Dialogs, StdCtrls,
    CHILKATHTTPLib_TLB,
    OleCtrls;

...

procedure TForm1.Button1Click(Sender: TObject);
var
http: TChilkatHttp;
success: Integer;
response: IChilkatHttpResponse;

begin
http := TChilkatHttp.Create(Self);

//  Any string unlocks the component for the 1st 30-days.
success := http.UnlockComponent('Anything for 30-day trial');
if (success <> 1) then
  begin
    ShowMessage(http.LastErrorText);
    Exit;
  end;

//  Send a HEAD request to get the response header:

response := http.GetHead('http://www.chilkatsoft.com/download/ChilkatDotNet2.msi');

if (response = nil ) then
  begin
    ShowMessage(http.LastErrorText);
  end
else
  begin

    //  The ContentLength property of the HTTP response is
    //  the size of the remote file:
    Memo1.Lines.Add('Size of download = ' + IntToStr(response.ContentLength));

  end;
end;