jmikola/wildcard-event-dispatcher-bundle

Enhances the Symfony2 event dispatcher with support for wildcard patterns inspired by AMQP topic exchanges.

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v1.0.2 2014-06-26 16:04 UTC

README

Build Status

This bundle integrates the WildcardEventDispatcher library with Symfony2 and allows event listeners to be assigned using a wildcard pattern inspired by AMQP topic exchanges.

Symfony2's event dispatcher component and the framework's existing convention for event names (dot-separated words) is already quite similar to AMQP message routing keys. This bundle is intended to be used sparingly, where wildcards may replace verbose configuration for central listeners, such as an activity logging service.

Some background info for this bundle may be found on the symfony-devs mailing list.

Compatibility

This bundle's master branch maintains compatibility with Symfony2's master branch. The 1.0.x tag for this bundle tracks its master branch.

There is no support for Symfony 2.0.x.

Configuration

There are no configuration options. Symfony2 will load the bundle's dependency injection extension automatically.

The extension will create a service that composes the existing event_dispatcher service and assumes its service ID. Depending on whether debug mode is enabled, this bundle may wrap an instance of FrameworkBundle's ContainerAwareEventDispatcher or TraceableEventDispatcher class.

Listening on Wildcard Event Patterns

This bundle enables you to use the single-word * and multi-word # wildcards when assigning event listeners. The wildcard operators are described in greater detail in the documentation for WildcardEventDispatcher.

Single-word Wildcard

Consider the scenario where the acme.listener service is currently listening on multiple core events:

<!-- Acme/MainBundle/Resources/config/listener.xml -->

<service id="acme.listener" class="Acme/MainBundle/Listener">
    <tag name="kernel.listener" event="core.exception" method="onCoreEvent" />
    <tag name="kernel.listener" event="core.request" method="onCoreEvent" />
    <tag name="kernel.listener" event="core.response" method="onCoreEvent" />
</service>

You could refactor the above configuration to use the single-word * wildcard:

<!-- Acme/MainBundle/Resources/config/listener.xml -->

<service id="acme.listener" class="Acme/MainBundle/Listener">
    <tag name="kernel.listener" event="core.*" method="onCoreEvent" />
</service>

This listener will now observe all events starting with core. and followed by another word. An event named core would also be matched by this pattern.

Multi-word Wildcard

Suppose there was an event in your application named core.foo.bar. The aforementioned core.* pattern would not match this event. You could use:

<!-- Acme/MainBundle/Resources/config/listener.xml -->

<service id="acme.listener" class="Acme/MainBundle/Listener">
    <tag name="kernel.listener" event="core.*.*" method="onCoreEvent" />
</service>

This syntax would match core.foo and core.foo.bar, but core would no longer be matched (assuming there was such an event); however, the multi-word # wildcard would allow all of these event names to be matched:

<!-- Acme/MainBundle/Resources/config/listener.xml -->

<service id="acme.listener" class="Acme/MainBundle/Listener">
    <tag name="kernel.listener" event="core.#" method="onCoreEvent" />
</service>

The # wildcard could also be used to listen to all events in the application:

<!-- Acme/MainBundle/Resources/config/listener.xml -->

<service id="acme.listener" class="Acme/MainBundle/Listener">
    <tag name="kernel.listener" event="#" method="onAnyEvent" />
</service>