获取公网IP

unit PublicIPGetter;

interface

function GetPublicIP: string;

implementation

uses
  SysUtils, Windows, Classes, UrlMon;

const
  cPublicIPQueryUrl: string = ‘http://city.ip138.com/ip2city.asp‘;

var
  _FileName: string;

function PublicIPFromPageText(const S: string): string;
const
  cIPStartToken = ‘[‘;
  cIPEndToken   = ‘]‘;
var
  I, J: Integer;
begin
  I := Pos(cIPStartToken, S);
  if I > 0 then
  begin
    J := Pos(cIPEndToken, S);
    if (J > 0) and (J > I) then
    begin
      Result := Copy(S, I + 1, J - I - 1);
      Exit;
    end;
  end;

  Result := ‘‘;
end;

function GetPublicIP: string;
var
  L: TStringList;
begin
  URLDownloadToFile(nil, PChar(cPublicIPQueryUrl), PChar(_FileName), 0, nil);
  L := TStringList.Create;
  L.LoadFromFile(_FileName);
  Result := PublicIPFromPageText(L.Text);
  FreeAndNil(L);
  DeleteFile(PChar(_FileName));
end;

initialization
  _FileName := ExtractFilePath(ParamStr(0)) + ‘_ip_addr_tmp_.txt‘;

end.