Doctrine allows you to register listeners and subscribers that are notified when different events occur inside Doctrine's ODM. For more information, see Doctrine's Event Documentation.
Each connection in Doctrine has its own event manager, which is shared with document managers tied to that connection. Listeners and subscribers may be registered with all event managers or just one (using the connection name).
In Symfony, you can register a listener or subscriber by creating a service and then tagging it with a specific tag.
doctrine_mongodb.odm.event_listener tag to
register a listener. The
event attribute is required and should denote
the event on which to listen. By default, listeners will be registered with
event managers for all connections. To restrict a listener to a single
connection, specify its name in the tag's
priority attribute, which defaults to
0 if omitted, may be used
to control the order that listeners are registered. Much like Symfony's
event dispatcher, greater numbers will result in the listener executing
first and listeners with the same priority will be executed in the order that
they were registered with the event manager.
lazy attribute, which defaults to
false if omitted, may
be used to request that the listener be lazily loaded by the event manager
when its event is dispatched.
to register a subscriber. Subscribers are responsible for implementing
Doctrine\Common\EventSubscriber and a method for returning the events
they will observe. For this reason, this tag has no
lazy attributes are
Unlike Symfony event listeners, Doctrine's event manager expects each
listener and subscriber to have a method name corresponding to the observed
event(s). For this reason, the aforementioned tags have no