The static method Zend_Loader::loadFile() loads a PHP file. The file loaded may contain any PHP code. The method is a wrapper for the PHP function include(). This method throws Zend_Exception on failure, for example if the specified file does not exist.

<?php

Zend_Loader::loadFile($filename, $dirs=null, $once=false)

?>

The $filename argument specifies the filename to load, which must not contain any path information. A security check is performed on $filename. The $filename may only contain alphanumeric characters, dashes ("-"), underscores ("_"), or periods ("."). No such restriction is placed on the $dirs argument.

The $dirs argument specifies directories to search for the file. If NULL, only the include_path is searched. If a string or an array, the directory or directories specified will be searched, and then the include_path.

The $once argument is a boolean. If TRUE, Zend_Loader::loadFile() uses the PHP function include_once() for loading the file, otherwise the PHP function include() is used.

The static method Zend_Loader::loadClass($class, $dirs) loads a PHP file and then checks for the existance of the class.

<?php

Zend_Loader::loadClass('Container_Tree',
    array(
        '/home/production/mylib',
        '/home/production/myapp'
    )
);

?>

The string specifying the class is converted to a relative path by substituting directory separates for underscores, and appending '.php'. In the example above, 'Container_Tree' becomes 'Container/Tree.php'.

If $dirs is a string or an array, Zend_Loader::loadClass() searches the directories in the order supplied. The first matching file is loaded. If the file does not exist in the specified $dirs, then the include_path for the PHP environment is searched.

If the file is not found or the class does not exist after the load, Zend_Loader::loadClass() throws a Zend_Exception.

Zend_Loader::loadFile() is used for loading, so the class name may only contain alphanumeric characters and the hyphen ('-'), underscore ('_'), and period ('.').

The static method Zend_Loader::isReadable($pathname) returns TRUE if a file at the specified pathname exists and is readable, FALSE otherwise.

<?php

if (Zend_Loader::isReadable($filename)) {
    // do something with $filename
}

?>

The $filename argument specifies the filename to check. This may contain path information. This method is a wrapper for the PHP function is_readable(). The PHP function does not search the include_path, while Zend_Loader::isReadable() does.

The Zend_Loader class contains a method you can register with the PHP SPL autoloader. Zend_Loader::autoload() is the callback method. As a convenience, Zend_Loader provides the registerAutoload() function register its autoload() method. If the spl_autoload extension is not present in your PHP environment, then registerAutoload() method throws a Zend_Exception.

<?php

Zend_Loader::registerAutoload();

?>

After registering the Zend Framework autoload callback, you can reference classes from the Zend Framework without having to load them explicitly. The autoload() method uses Zend_Loader::loadClass() automatically when you reference a class.

If you have extended the Zend_Loader class, you can give an optional argument to registerAutoload(), to specify the class from which to register an autoload() method.

<?php

class My_Loader extends Zend_Loader
{
    // custom functionality
}

Zend_Loader::registerAutoload('My_Loader');

?>