(Delphi ActiveX) HTTPS Server Certificate Require Hostname Match

See more HTTP Examples

Note: This example requires Chilkat v11.0.0 or greater.

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
http: TChilkatHttp;
html: WideString;

begin
// The RequireHostnameMatch property was added in Chilkat v11.0.0
// to ensure the URL's hostname matches at least one of the server certificate SAN's (Subject Alternative Names)
// 
// In actuality, it is the SNI hostname that must match.  If the SNI hostname is not explicitly set,
// then Chilkat uses the hostname from the URL as the SNI hostname.

// Here's an example using chilkatsoft.com
// The SSL server certificate for chilkatsoft.com has 2 Subject Alternative Names:
// 
// 1) DNS Name: *.chilkatsoft.com
// 2) DNS Name: chilkatsoft.com
// 
// See Explaining the SNI Hostname in TLS

http := TChilkatHttp.Create(Self);

http.RequireHostnameMatch := 1;

// This should succeed because "www.chilkatsoft.com" matches the SAN entry "*.chilkatsoft.com"
html := http.QuickGetStr('https://www.chilkatsoft.com/helloWorld.html');
Memo1.Lines.Add('1) Succeeded: ' + IntToStr(Ord(http.LastMethodSuccess)));

// At the time of writing this example, the IP address for chilkatsoft.com is 3.101.18.47
// If we send the request using the IP address, it will fail because the IP address is does 
// not match any of the SAN entries in the server certificate.
html := http.QuickGetStr('https://3.101.18.47/helloWorld.html');
Memo1.Lines.Add('2) Succeeded: ' + IntToStr(Ord(http.LastMethodSuccess)));

// However, it will succeed if we explicitly set the SNI hostname.
http.SniHostname := 'www.chilkatsoft.com';
html := http.QuickGetStr('https://3.101.18.47/helloWorld.html');
Memo1.Lines.Add('3) Succeeded: ' + IntToStr(Ord(http.LastMethodSuccess)));

// Remove our explicit SNI hostname.
http.SniHostname := '';

// Now let's try wrong.host.badssl.com
// The SSL server certificate for badssl.com has 2 Subject Alternative Names:
// 
// 1) DNS Name: *.badssl.com
// 2) DNS Name: badssl.com

// The domain wrong.host.badssl.com will fail the RequireHostnameMatch because
// the wildcarded domain SAN entry only extends 1 level deep.  
html := http.QuickGetStr('https://wrong.host.badssl.com/');
Memo1.Lines.Add('4) Succeeded: ' + IntToStr(Ord(http.LastMethodSuccess)));

// The expected output is:
// 1) Succeeded: True
// 2) Succeeded: False
// 3) Succeeded: True
// 4) Succeeded: False
end;