(Delphi ActiveX) DNS Query MX Records

See more DNS Examples

Shows how to perform a DNS query to retrieve MX records.

Note: This example requires Chilkat v9.5.0.96 or later.

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
dns: TChilkatDns;
json: TChilkatJsonObject;
success: Integer;
name: WideString;
ttl: Integer;
pref: Integer;
domain: WideString;
i: Integer;
count_i: Integer;

begin
dns := TChilkatDns.Create(Self);

json := TChilkatJsonObject.Create(Self);
json.EmitCompact := 0;

success := dns.Query('MX','somebody@gmail.com',json.ControlInterface);
if (success = 0) then
  begin
    Memo1.Lines.Add(dns.LastErrorText);
    Exit;
  end;

Memo1.Lines.Add(json.Emit());

// Sample response.
// Parsing code below..

// -------------------------------------------------------------------------------
// Note: Chilkat will return the results sorted by "pref" from lowest to highest.
// -------------------------------------------------------------------------------

// {
//   "answer": {
//     "mx": [
//       {
//         "name": "gmail.com",
//         "ttl": 491,
//         "pref": 5,
//         "domain": "gmail-smtp-in.l.google.com"
//       },
//       {
//         "name": "gmail.com",
//         "ttl": 491,
//         "pref": 10,
//         "domain": "alt1.gmail-smtp-in.l.google.com"
//       },
//       {
//         "name": "gmail.com",
//         "ttl": 491,
//         "pref": 20,
//         "domain": "alt2.gmail-smtp-in.l.google.com"
//       },
//       {
//         "name": "gmail.com",
//         "ttl": 491,
//         "pref": 30,
//         "domain": "alt3.gmail-smtp-in.l.google.com"
//       },
//       {
//         "name": "gmail.com",
//         "ttl": 491,
//         "pref": 40,
//         "domain": "alt4.gmail-smtp-in.l.google.com"
//       }
//     ]
//   }
// }

// Use this online tool to generate parsing code from sample JSON: 
// Generate Parsing Code from JSON

i := 0;
count_i := json.SizeOfArray('answer.mx');
while i < count_i do
  begin
    json.I := i;
    name := json.StringOf('answer.mx[i].name');
    ttl := json.IntOf('answer.mx[i].ttl');
    pref := json.IntOf('answer.mx[i].pref');
    domain := json.StringOf('answer.mx[i].domain');
    i := i + 1;
  end;
end;