Pascal (Lazarus/Delphi)

Get Size of File on Web Server

See more HTTP Examples

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. Pascal (Lazarus/Delphi)

program ChilkatDemo;

// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.

{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}

uses
  {$IFDEF UNIX}
  cthreads,
  {$ENDIF}
  SysUtils,
  CkDllLoader,
  Chilkat.HttpResponse,
  Chilkat.Http;

// ---------------------------------------------------------------------------

procedure RunDemo;
var
  success: Boolean;
  http: THttp;
  resp: THttpResponse;
  contentLengthStr: string;

begin
  success := False;

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

  http := THttp.Create;

  resp := THttpResponse.Create;
  success := http.HttpNoBody('HEAD','https://nodejs.org/dist/v10.16.1/node-v10.16.1-win-x64.zip',resp);
  if (success = False) then
    begin
      WriteLn(http.LastErrorText);
      Exit;
    end;

  //  Examine the response header.
  WriteLn(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.
  contentLengthStr := resp.GetHeaderField('Content-Length');
  //  If the header exists...
  if (resp.LastMethodSuccess = True) then
    begin
      WriteLn('Content-Length: ' + contentLengthStr);
      //  Your application can convert the contentLengthStr to an integer and then use it....
    end;


  http.Free;
  resp.Free;

end;

// ---------------------------------------------------------------------------

begin

  try
    RunDemo;
  except
    on E: Exception do
      WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
  end;

  WriteLn;
  {$IFDEF MSWINDOWS}
  WriteLn('Press Enter to exit...');
  ReadLn;
  {$ENDIF}
end.