Get Size of Download using HTTP HEAD

Get the size of a download using an HTTP 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;
resp: IChilkatHttpResponse;
sizeStr: String;

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);

  end;

resp := http.GetHead('http://www.chilkatsoft.com/download/ChilkatDotNet2.msi');
if (resp = nil ) then
  begin
    ShowMessage(http.LastErrorText);
  end
else
  begin

    sizeStr := resp.GetHeaderField('Content-Length');
    if (sizeStr = NULL ) then
      begin
        ShowMessage('No content-length header field');
      end
    else
      begin
        //  Show the size of the file.
        //  You may convert the size string to an integer...
        ShowMessage(sizeStr);
      end;
  end;
end;