Simple, session-persistent error handling

error.php

<?php
  class ErrorStack {
    private $errorPage;
    private $stack;

    function __construct($errorPage = 'showErrors.php') {
      $this->errorPage = $errorPage;
    }

    public function add($desc) {
      global $currentFile;

      if ($currentFile != $this->errorPage) {
        $this->stack[] = array('timestamp'   => time(),
                               'description' => $desc);
      }
    }

    public function show() {
      if (is_array($this->stack)) {
        return array_reverse($this->stack);
      } else {
        return false;
      }
    }

    public function complain() {
      global $currentFile;

      if (count($this->stack) > 0 && $currentFile != $this->errorPage) {
        $pickled = serialize($this);
        $_SESSION['err'] = $pickled;

        @header('Location: '.$this->errorPage);
        exit;
      }
    }
  }

  // Initialise
  // (n.b., Needs to be within a session)
  if (isset($_SESSION['err'])) {
    $err = unserialize($_SESSION['err']);
  } else {
    $err = new ErrorStack();
  }
?>

test.php

<?php
  session_destroy();
  session_start();

  $currentFile = end(explode('/', $_SERVER['PHP_SELF']));

  include "error.php";

  // I don't work after 5pm
  if (date("G") >= 17) {
    $err->add('Go away! Sleeping!');
  }

  $err->complain();
?>

This is a very simple error handling class: You add errors to the stack, as-and-when they occur, using the add('Error text') method; after everything that could have gone wrong, call complain(), which will redirect you to an error page (defaults to showErrors.php, but can be changed at construction) if there are any problems. The error page can then use show() to output the stack, which also includes UNIX timestamps.

To persist the error data across pages, you can simply serialise the class into a session variable (which, of course, requires you to do the session handling first). Also note that the global $currentFile indicates the filename of the currently running script. I know global state isn't cool, but fuck: it's PHP! What do you want!?

Forked into php-stack