Detect an HTTP proxy from an Opera installation

Problem/Question/Abstract:

Detect an HTTP proxy from an Opera installation

Answer:

For the uncommon situation that a user does not have IE installed, one could try to retrieve the proxy information from an Opera installation.

Opera software stores in the registry the directory in that the Opera browser is installed.

In this directory there is a configuration file "Opera.ini" that contains a [PROXY] section. This section holds the required information.
The following handy routine shows how to code it:

procedure TForm1.FormCreate(Sender: TObject);
var
  OperaDir: string;
  sResult: string;
begin
  // get Proxy host info from an Opera installation!
  with TRegistry.Create do
  begin
    sResult := '';
    RootKey := HKEY_CURRENT_USER;
    if OpenKey('\Software\Opera Software', false) then
    begin
      if ValueExists('Last Directory') then
      begin
        OperaDir := ReadString('Last Directory');
        SetLength(sResult, 128);
        SetLength(sResult,
          GetPrivateProfileString(
          'PROXY',
          'HTTP Server',
          '',
          @sResult[1],
          Length(sResult),
          PChar(OperaDir + '\opera.ini')));
      end;
    end;
    Free;
    if sResult <> '' then
      ShowMessage('Your http proxy is ' + sResult)
    else
      ShowMessage('Opera is not installed or no proxy found.');
  end;
end;