Question

I use the class below to route all requests for php on my web application. Can I improve upon this?

/*route*/

class route
  {
  function __construct($a) 
    {
    if(isset($_FILES['ufile']['tmp_name']))  // handles file uploads
      {
      new upload();
      }
    elseif(isset($_POST['a'])) // handles AJAX
      {
      $b=$_POST['a']; 
      switch($b) 
        {
        case '0': 
          new signin(); 
          break; 
        case '1': 
          new signup(); 
          break; 
        case '2': 
          session::finish(); 
          break; 
        case '3': 
          new bookmark('insert'); 
          break; 
        case '3a': 
          new bookmark('delete'); 
          break; 
        case '4': 
          new tweet(); 
          break;
        default:
          echo "ajax route not found";
          break;
        }
      } 
    elseif($a!=0)  // handles views
      {
      new view($a);
      }
    else
      {
      // route not found
      }
    }
  }

Verification(passes)

/*ROUTE
// Test Code - create entry
  new route(0);
  new route(1);
  $_FILES['ufile']['tmp_name']='test file';
  new route(0);
  unset($_FILES['ufile']['tmp_name']); 
  $_POST['a']=0;
  new route(0);
// Test Cases
  // Case 0:      echo "not routed: <br>";
  // Case 1:      echo "view created: $a <br>";
  // Case 2:      echo "file uploaded <br>";
  // Case 3:      echo "ajax responded: <br>";
*/

Answer 1

    public static function route($a)
    {
    // The first if statement is redundant this line will accomplish the
    // same as the if/else because if post[a] is not set it will become null
       $b=$_POST["a"];
    // now that b is a, it's really one switch statement
   if( $b==0 && $a==0 )
       switch( $b )
       {
         case '0':
           new signin();
           break;
         case '1':
           new signup();
           general::upload();
           break;
         case '2':
           session::finish();
           break;
         case '3':
           new bookmark('insert');
           break;
         case '3a':
           new bookmark('delete');
           break;
         case '4':
           new tweet();
           break;
         default:
           view::posts_all();
           break
       }
     }elseif( $a==1 )
         view::bookmarks();
     else
         view::posts_all();

Give that a go, Good luck. (A side note: the quotation marks on the numeric cases are optional, the 3a is not. I left them in there because they were in the original. You could reduce it further by getting rid of $b entirely and running the switch on $_POST[‘a’] )