QueryPath extensions should call the QueryPath::ExtensionRegistry::extend()
function to register their extension classes. The QueryPath library then
uses this information to determine what QueryPath extensions should be loaded and
executed.
Extensions are attached to a Query object.
To enable an extension (the easy way), use QueryPath::enable().
This class provides lower-level interaction with the extension
mechanism.
/**
* @expectedException \QueryPath\Exception
*/
public function testAutoloadExtensions()
{
// FIXME: This isn't really much of a test.
ExtensionRegistry::autoloadExtensions(FALSE);
try {
qp()->stubToe();
} catch (Exception $e) {
ExtensionRegistry::autoloadExtensions(TRUE);
throw $e;
}
}
/**
* Get a list of all of the enabled extensions.
*
* This example dumps a list of extensions to standard output:
* @code
* <?php
* $extensions = QueryPath::enabledExtensions();
* print_r($extensions);
* ?>
* @endcode
*
* @retval array
* An array of extension names.
*
* @see QueryPath::ExtensionRegistry
*/
public static function enabledExtensions()
{
return \QueryPath\ExtensionRegistry::extensionNames();
}
/**
* Call extension methods.
*
* This function is used to invoke extension methods. It searches the
* registered extenstensions for a matching function name. If one is found,
* it is executed with the arguments in the $arguments array.
*
* @throws QueryPath::Exception
* An exception is thrown if a non-existent method is called.
*/
public function __call($name, $arguments)
{
if (!ExtensionRegistry::$useRegistry) {
throw new \QueryPath\Exception("No method named {$name} found (Extensions disabled).");
}
// Loading of extensions is deferred until the first time a
// non-core method is called. This makes constructing faster, but it
// may make the first invocation of __call() slower (if there are
// enough extensions.)
//
// The main reason for moving this out of the constructor is that most
// new DOMQuery instances do not use extensions. Charging qp() calls
// with the additional hit is not a good idea.
//
// Also, this will at least limit the number of circular references.
if (empty($this->ext)) {
// Load the registry
$this->ext = ExtensionRegistry::getExtensions($this);
}
// Note that an empty ext registry indicates that extensions are disabled.
if (!empty($this->ext) && ExtensionRegistry::hasMethod($name)) {
$owner = ExtensionRegistry::getMethodClass($name);
$method = new \ReflectionMethod($owner, $name);
return $method->invokeArgs($this->ext[$owner], $arguments);
}
throw new \QueryPath\Exception("No method named {$name} found. Possibly missing an extension.");
}