Global event handler. More...

Collaboration diagram for ilAppEventHandler:

Public Member Functions
	__construct ()

	raise (string $a_component, string $a_event, array $a_parameter=[])
	Raise an event. More...

Protected Member Functions
	initListeners ()

Protected Attributes
ilDBInterface	$db

array	$listener

ilLogger	$logger

ilComponentRepository	$component_repository

ilComponentFactory	$component_factory

Detailed Description

Global event handler.

The event handler delegates application events (not gui events) between components that trigger events and components that listen to events. A component is a module or a service.

The component that triggers an event calls the raise function of the event handler through the global instance ilAppEventHandler:

E.g. in ilObjUser->delete(): $ilAppEventHandler->raise("Services/User", "deleteUser", array("id" => ..., ...))

A listener has to subscribe to the events of another component. This currently is done here in the constructor, e.g. if the News service listens to the User service, add a $this->listener["Services/User"] = array("Services/News"); This information will go to xml files in the future.

A component has to implement a listener class that implements Services/EventHandling/interfaces/interface.ilAppEventListener.php

The location must be <component>/classes/class.il<comp_name>AppEventListener.php, e.g. ./Services/News/classes/class.ilNewsAppEventListener.php

The class name must be il<comp_name>AppEventListener.

Author: Alex Killing alex..nosp@m.kill.nosp@m.ing@g.nosp@m.mx.d.nosp@m.e; Fabian Schmid fs@st.nosp@m.uder.nosp@m.-raim.nosp@m.ann..nosp@m.ch

Definition at line 51 of file class.ilAppEventHandler.php.

Constructor & Destructor Documentation

◆ __construct()

ilAppEventHandler::__construct ( )

Definition at line 59 of file class.ilAppEventHandler.php.

    {
        global $DIC;
 
        $this->db = $DIC->database();
        $this->component_repository = $DIC["component.repository"];
        $this->component_factory = $DIC["component.factory"];
        $this->initListeners();
 
        $this->logger = \ilLoggerFactory::getLogger('evnt');
    }

References $DIC, ilLoggerFactory\getLogger(), initListeners(), and ILIAS\Repository\logger().

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Member Function Documentation

◆ initListeners()

ilAppEventHandler::initListeners ( )

protected

Definition at line 71 of file class.ilAppEventHandler.php.

                                      : void
    {
        $ilGlobalCache = ilGlobalCache::getInstance(ilGlobalCache::COMP_EVENTS);
        $cached_listeners = $ilGlobalCache->get('listeners');
        if (is_array($cached_listeners)) {
            $this->listener = $cached_listeners;
 
            return;
        }
 
        $ilDB = $this->db;
 
        $this->listener = array();
 
        $sql = "SELECT * FROM il_event_handling" .
            " WHERE type = " . $ilDB->quote("listen", "text");
        $res = $ilDB->query($sql);
        while ($row = $ilDB->fetchAssoc($res)) {
            $this->listener[$row["id"]][] = $row["component"];
        }
 
        $ilGlobalCache->set('listeners', $this->listener);
    }

References $db, $ilDB, $res, ilGlobalCache\COMP_EVENTS, and ilGlobalCache\getInstance().

Referenced by __construct().

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◆ raise()

ilAppEventHandler::raise	(	string	$a_component,
		string	$a_event,
		array	$a_parameter = `[]`
	)

Raise an event.

The event is passed to all interested listeners.

Parameters

string	$a_component	component, e.g. "Modules/Forum" or "Services/User"
string	$a_event	event e.g. "createUser", "updateUser", "deleteUser", ...
array	$a_parameter	parameter array (assoc), array("name" => ..., "phone_office" => ...)

Definition at line 102 of file class.ilAppEventHandler.php.

     : void {
        $this->logger->debug(sprintf(
            "Received event '%s' from component '%s'.",
            $a_event,
            $a_component
        ));
 
        $parameter_formatter = static function ($value) use (&$parameter_formatter) {
            if (is_object($value)) {
                return get_class($value);
            }
 
            if (is_array($value)) {
                return array_map(
                    $parameter_formatter,
                    $value
                );
            }
 
            return $value;
        };
 
        $this->logger->debug('Event data: ' . var_export(array_map(
            $parameter_formatter,
            $a_parameter
        ), true));
 
        $this->logger->debug("Started event propagation for event listeners ...");
 
        if (is_array($this->listener[$a_component] ?? null)) {
            foreach ($this->listener[$a_component] as $listener) {
                // Allow listeners like Services/WebServices/ECS
                $last_slash = strripos($listener, '/');
                $comp = substr($listener, 0, $last_slash);
 
                // any kind of plugins with events in their plugin.xml
                if ($comp == 'Plugins') {
                    $name = substr($listener, $last_slash + 1);
 
 
                    foreach ($this->component_repository->getPlugins() as $pl) {
                        if ($pl->getName() !== $name || !$pl->isActive()) {
                            continue;
                        }
                        $plugin = $this->component_factory->getPlugin($pl->getId());
                        $plugin->handleEvent($a_component, $a_event, $a_parameter);
                    }
                } else {
                    $class = 'il' . substr($listener, $last_slash + 1) . 'AppEventListener';
                    $file = "./" . $listener . "/classes/class." . $class . ".php";
                    // if file exists, call listener
                    if (is_file($file)) {
                        include_once($file);
                        call_user_func(array($class, 'handleEvent'), $a_component, $a_event, $a_parameter);
                    }
                }
            }
        }
 
        $this->logger->debug("Finished event listener handling, started event propagation for event hook plugins ...");
 
        // get all event hook plugins and forward the event to them
        foreach ($this->component_factory->getActivePluginsInSlot("evhk") as $plugin) {
            $plugin->handleEvent($a_component, $a_event, $a_parameter);
        }
    }