Delphi DLL

Resolve Domain to IP Address

See more DNS Examples

Demonstrates how to perform a DNS query to obtain A records for resolving a domain name to an IPv4 address. Delphi DLL

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

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Boolean;
dns: HCkDns;
json: HCkJsonObject;
name: PWideChar;
ttl: Integer;
ipv4: PWideChar;
i: Integer;
count_i: Integer;

begin
success := False;

dns := CkDns_Create();

json := CkJsonObject_Create();
CkJsonObject_putEmitCompact(json,False);

success := CkDns_Query(dns,'A','microsoft.com',json);
if (success = False) then
  begin
    Memo1.Lines.Add(CkDns__lastErrorText(dns));
    Exit;
  end;

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

// 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 := CkJsonObject_SizeOfArray(json,'answer.a');
while i < count_i do
  begin
    CkJsonObject_putI(json,i);
    name := CkJsonObject__stringOf(json,'answer.a[i].name');
    ttl := CkJsonObject_IntOf(json,'answer.a[i].ttl');
    ipv4 := CkJsonObject__stringOf(json,'answer.a[i].ipv4');
    i := i + 1;
  end;

CkDns_Dispose(dns);
CkJsonObject_Dispose(json);

end;