title: Laravel Route::get using where conditions
body: <p>I'm working on Laravel 5.1 and I have the following code:</p>
  
  <pre><code>//Routes.php
  Route::get('/listagem/{campo}','ControllerParque@listar');
  
  //ControllerParque.php
      public function listar($campo) {       
          $listagem = DB::SELECT("SELECT COUNT(x.".$campo.") AS nreg, x.* FROM (SELECT * FROM computadores ORDER BY id DESC) AS x GROUP BY ".$campo." ORDER BY ".$campo." ASC");  
          $dados = array('listagem' =&gt; $listagem, 'campo' =&gt; $campo);
          return view("ViewListagem")-&gt;with($dados);           
      }
  </code></pre>
  
  <p>I would like to restrict anything different of 'listagem/usuario' or 'listagem/tag'. I mean, if an user types in your navigator (URL bar) 'listagem/crap', it will be denied, because it's not 'listagem/usuario' or 'listagem/tag'.</p>
  
  <p>I've tried 'where' clause':</p>
  
  <pre><code>Routes.php
      Route::get('/listagem/{campo}','ControllerParque@listar')
  -&gt;where('campo', 'usuario');
  </code></pre>
  
  <p>But this way I'm restricting just the one condition, this case 'listagem/usuario'.</p>
  
  <p>Any idea?</p>