index.md

Fmasa/Messenger

The usage is nearly identical to Symfony implementation. There is difference in convention - this integration uses camelCase everywhere instead of snake_case.

Register extension in your config file using:

extensions:
    messenger: Fmasa\Messenger\DI\MessengerExtension

Buses

By default there is no default bus. You can define your named buses as follows:

messenger:
    buses:
      commandBus:
      eventBus:

This will create services @messenger.commandBus.bus and @messenger.eventBus.bus of type MessageBusInterface in your container. You can wrap those using custom class to provide autowiring.

Middleware

By default only registered middleware is the one that passes message to handlers.

There are more of these you might want to use. You can register them like via middleware option:

messenger:
    buses:
        commandBus:
            middleware:
                - MyCustomMiddleware()
                - @registeredServiceMiddleware

See more about middleware in Symfony docs.

Handlers

Valid handler is callable class with __invoke() method. The invoke method musts take exactly one required parameter with class/interface typehint.

Extension automatically registers all services implementing Symfony\Component\Messenger\Handler\MessageHandlerInterface or using tag messenger.messageHandler as message handlers (this tag is used for all additional handler configuration.

Handlers are by default registered to all buses. This can be changed via bus option. In this example, RegisterUserHandler will be registered only to bus called commandBus:

messenger:
    buses:
        commandBus:
        queryBus:

services:
    - class: RegisterUserHandler
      tags:
          messenger.messageHandler:
              bus: commandBus

Handler aliases

By default different services of same class are treated as unique handlers. In this case, both handler @a and @b will be called:

services:
    a:
        class: RegisterUserHandler
        tags: [messenger.messageHandler]
    b:
        class: RegisterUserHandler
        tags: [messenger.messageHandler]

This can be changed using handler aliases. Now only first defined handler will be called.

    a:
        class: RegisterUserHandler
        tags: [messenger.messageHandler]
    b:
        class: RegisterUserHandler
        tags:
            messenger.messageHandler:
                alias: a # Default value is current service name

Your aliases don't need to match service names, these can be arbitrary strings.

Debugger panel

The extension automatically registers panel to Tracy bar. This allows you to see all handled messages in current request with responses.

Debugger can be disabled on per-bus basis:

messenger:
    buses:
        commandBus: # Has panel
        queryBus: # Does not have panel
            panel: false

Recommended usage

• Message bus wrappers