TOPIC:

uses
  Classes, SysUtils, FileUtil, IdHTTPServer, DaemonApp, Interfaces, IdCustomHTTPServer,
  IdContext, IdGlobal;

type

  { TDaemon1 }

  TDaemon1 = class(TDaemon)
    IdHTTPServer1: TIdHTTPServer;
    procedure DataModuleCreate(Sender: TObject);
    procedure DataModuleExecute(Sender: TCustomDaemon);
    procedure IdHTTPServer1CommandGet(AContext: TIdContext;
      ARequestInfo: TIdHTTPRequestInfo; AResponseInfo: TIdHTTPResponseInfo);
  private
    { private declarations }
  public
    { public declarations }
  end;

var
  Daemon1: TDaemon1;

implementation

procedure RegisterDaemon;
begin
  RegisterDaemonClass(TDaemon1)
end;

{$R *.lfm}

{ TDaemon1 }

procedure TDaemon1.DataModuleCreate(Sender: TObject);
begin
  IdHTTPServer1.Bindings.Add.IPVersion:=Id_IPv4;
  IdHTTPServer1.DefaultPort:=8081;
  IdHTTPServer1.Active:=true;
end;

procedure TDaemon1.DataModuleExecute(Sender: TCustomDaemon);
begin

end;

procedure TDaemon1.IdHTTPServer1CommandGet(AContext: TIdContext;
  ARequestInfo: TIdHTTPRequestInfo; AResponseInfo: TIdHTTPResponseInfo);
begin
  AResponseInfo.ContentType:='text/plain';
  AResponseInfo.ContentText:='Hello world!';
  AResponseInfo.WriteHeader;
  AResponseInfo.WriteContent;
end;

initialization
  RegisterDaemon;
end.