(Delphi ActiveX) HTTP - Verify Server is a Trusted Root CA

Demonstrates how to only allow connections to an HTTP server having a certificate with a root that is in our list of trusted CA root certificates.

Chilkat for Delphi Downloads Chilkat ActiveX DLL for Delphi Chilkat non-ActiveX DLL for Delphi * The examples here use the ActiveX DLL.

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Chilkat_TLB;

...

procedure TForm1.Button1Click(Sender: TObject);
var
chilkatGlob: TChilkatGlobal;
success: Integer;
url: WideString;
http: TChilkatHttp;
html: WideString;
trustedRoots: TChilkatTrustedRoots;

begin
// Starting in v9.5.0.49, all Chilkat classes can be unlocked at once at the beginning of a program
// by calling UnlockBundle.  It requires a Bundle unlock code.
chilkatGlob := TChilkatGlobal.Create(Self);
success := chilkatGlob.UnlockBundle('Anything for 30-day trial.');
if (success <> 1) then
  begin
    Memo1.Lines.Add(chilkatGlob.LastErrorText);
    Exit;
  end;

//  On my particular system, the root CA cert for this URL is not pre-installed.
//  Note: This may be different for you.
//  Also, this example was written on 29-May-2015.  This URL was valid at the time,
//  but may not be valid at a future date.
url := 'https://animals.nationalgeographic.com/animals/invertebrates/starfish/';

http := TChilkatHttp.Create(Self);

//  Require that the SSL/TLS server certificate is not expired,
//  and that the certificate signature is valid.
//  This does not ensure that it has a chain of authentication to
//  a trusted root.  To ensure that, the TrustedRoots object (below) is required.
http.RequireSslCertVerify := 1;

//  Do the HTTPS page fetch (through the SSH tunnel)
html := http.QuickGetStr(url);
if (http.LastMethodSuccess <> 1) then
  begin
    Memo1.Lines.Add(http.LastErrorText);
    Exit;
  end;

Memo1.Lines.Add('The HTTP GET was successful.');

//  Now let's require that HTTP requests to SSL/TLS servers that don't have trusted CA roots
//  should fail.
trustedRoots := TChilkatTrustedRoots.Create(Self);

//  Indicate that we will trust any pre-installed certificates on this system.
//  (The meaning of pre-installed certificates depends on the operating system, and in
//  some environments there is no such thing as pre-installed certificates.  See the reference
//  documentation for the TrustedRoots class.)
trustedRoots.TrustSystemCaRoots := 1;

//  Activate the trusted roots globally for all Chilkat objects.
//  This call really shouldn't fail, so we're not checking the return value.
success := trustedRoots.Activate();

//  Given that our previous HTTP GET likely kept the connection open,
//  make sure that all HTTP connections are closed before re-trying.
//  Otherwise, we'll simply be re-using the pre-existing connection.
success := http.CloseAllConnections();

//  Now let's try fetching the URL again.  It should fail this time because
//  there is a requirement that the SSL/TLS server certificate must have a trusted root,
//  and the trusted root for this URL is not installed on my system (but may be different for you..)
html := http.QuickGetStr(url);
if (http.LastMethodSuccess <> 1) then
  begin
    Memo1.Lines.Add(http.LastErrorText);
    Memo1.Lines.Add('Good, the HTTP request failed as expected.');
  end
else
  begin
    Memo1.Lines.Add(http.LastErrorText);
    Memo1.Lines.Add('Hmmm... we did not fail as expected?');
  end;
end;