Delphi ActiveX

DNS Query A Records

See more DNS Examples

Shows how to perform a DNS query to retrieve A records. Delphi ActiveX

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
success: Integer;
dns: TChilkatDns;
json: TChilkatJsonObject;
name: WideString;
ttl: Integer;
ipv4: WideString;
i: Integer;
count_i: Integer;

begin
success := 0;

dns := TChilkatDns.Create(Self);

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

success := dns.Query('A','microsoft.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..

// {
//   "answer": {
//     "a": [
//       {
//         "name": "microsoft.com",
//         "ttl": 1528,
//         "ipv4": "20.112.250.133"
//       },
//       {
//         "name": "microsoft.com",
//         "ttl": 1528,
//         "ipv4": "20.231.239.246"
//       },
//       {
//         "name": "microsoft.com",
//         "ttl": 1528,
//         "ipv4": "20.76.201.171"
//       },
//       {
//         "name": "microsoft.com",
//         "ttl": 1528,
//         "ipv4": "20.70.246.20"
//       },
//       {
//         "name": "microsoft.com",
//         "ttl": 1528,
//         "ipv4": "20.236.44.162"
//       }
//     ]
//   }
// }

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

i := 0;
count_i := json.SizeOfArray('answer.a');
while i < count_i do
  begin
    json.I := i;
    name := json.StringOf('answer.a[i].name');
    ttl := json.IntOf('answer.a[i].ttl');
    ipv4 := json.StringOf('answer.a[i].ipv4');
    i := i + 1;
  end;
end;