(Delphi DLL) Transition from MailMan.MxLookup to Dns.Query

Provides instructions for replacing deprecated MxLookup method calls with the Chilkat Dns class.

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

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

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

...

procedure TForm1.Button1Click(Sender: TObject);
var
mailman: HCkMailMan;
emailAddr: PWideChar;
domain: PWideChar;
dns: HCkDns;
json: HCkJsonObject;
success: Boolean;
i: Integer;
count_i: Integer;

begin
mailman := CkMailMan_Create();

// ...
// ...

emailAddr := 'joe@example.com';

// ------------------------------------------------------------------------
// The MxLookup method is deprecated:

domain := CkMailMan__mxLookup(mailman,emailAddr);
if (CkMailMan_getLastMethodSuccess(mailman) = False) then
  begin
    Memo1.Lines.Add(CkMailMan__lastErrorText(mailman));
    Exit;
  end;

// ------------------------------------------------------------------------
// Do the equivalent using the Chilkat DNS class

dns := CkDns_Create();

json := CkJsonObject_Create();

// This gets all MX domains for an email address.  (Typically one domain.)
// The preferred domain will be at index 0 (see below).
success := CkDns_Query(dns,'MX',emailAddr,json);
if (success = False) then
  begin
    Memo1.Lines.Add(CkDns__lastErrorText(dns));
    Exit;
  end;

i := 0;
count_i := CkJsonObject_SizeOfArray(json,'answer.mx');
while i < count_i do
  begin
    CkJsonObject_putI(json,i);
    domain := CkJsonObject__stringOf(json,'answer.mx[i].domain');
    Memo1.Lines.Add(domain);
    i := i + 1;
  end;

CkMailMan_Dispose(mailman);
CkDns_Dispose(dns);
CkJsonObject_Dispose(json);

end;