title: How to ignore specific attributes in Laravel's ConvertEmptyStringsToNull?
body: <p>Laravel includes a global middleware called <a href="https://github.com/laravel/framework/blob/f578bbce25843492fc996ac96797e0395e16cf2e/src/Illuminate/Foundation/Http/Middleware/ConvertEmptyStringsToNull.php" rel="nofollow noreferrer"><code>ConvertEmptyStringsToNull</code></a></p>
  
  <p>With the middleware, a request to <code>GET /somewhere?something</code> results in <code>something === null</code></p>
  
  <p>Without the middleware, this request results in <code>something === ''</code></p>
  
  <p><strong>How can I disable it for specific attribute names?</strong></p>
  
  <p>For example, if you look at another globally included middleware <a href="https://github.com/laravel/framework/blob/a67aeeb68bad370efa91eaa9825db9abdae7c72c/src/Illuminate/Foundation/Http/Middleware/TrimStrings.php" rel="nofollow noreferrer"><code>TrimStrings</code></a> you'll notice it contains an <code>except</code> property.</p>
  
  <pre><code>/**
   * The attributes that should not be trimmed.
   *
   * @var array
   */
  protected $except = [
      //
  ];
  </code></pre>
  
  <p>In this case, the middleware is applied to every attribute except those named here. I tried extending <code>ConvertEmptyStringsToNull</code> in the same manner, but it doesn't work. I feel like I'm missing something basic.</p>
  
  <p>I would like to be able to add exceptions for this middleware so that I get the empty string only for specific attribute names. e.g. except <code>exemption</code></p>
  
  <ul>
  <li><code>GET /somewhere?something</code> : <code>something === null</code></li>
  <li><code>GET /somewhere?exemption</code> : <code>exemption === ''</code></li>
  <li><code>GET /somewhere?everything</code> : <code>everything === null</code></li>
  </ul>