Developer Area/Pagetop Constants
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Mahara uses a diverse range of PHP constants defined at the beginning of the script, to define the script's behavior or provide metadata. This page attempts to be a comprehensive list of these constants and what they do.
Note: By all means make use of the existing set of page-top constants, but please avoid creating new ones whenever possible. They're a form of global variable, and as such they bring all the associated problems with them. They also tend not to be well-documented, because there's no central place in the code where they have to be used.
INTERNAL
This backwards-named constant tells Mahara that it's okay to access this page externally.
Every Mahara script that is meant to be addressed directly by a web browser (or other HTTP client) should define it as its very first PHP statement, even before including init.php.
define('INTERNAL', 1);
Conversely, every "library" script which is not meant to be addressed directly by a web browser, should begin with this:
defined('INTERNAL') || die();