Middleware

Hi John Esteban!

Hmm. I've never done this before, but yes, I think this is definitely doable. One of the things you need to have in any middleware is this line:

return $stack->next()->handle($envelope, $stack);

Example: https://github.com/symfony/symfony/blob/8e8207bb72d7f2cb8be355994ad2fcfa97c00f74/src/Symfony/Component/Messenger/Middleware/AddBusNameStampMiddleware.php#L37

This is literally what calls the NEXT item in the middleware. If you changed this, instead to:

return $envelope.

Then I'm pretty sure that the rest of the middleware change would not execute. So as long as your middleware is put before the "handle message" middleware (and this will happen automatically), then this should do the trick.

Let me know if you're successful.

Cheers!

Hey Jeff Groves !

I'm trying to figure out how to using the Symfony Messenger component in a non-Symfony application

Ah yes :). This is (as you correctly noticed) not the "first class citizen use case" in the docs - it's tricky, we have to write the docs primarily for the main audience. That, indeed, makes the "standalone component" usage trickier!

So let's talk about SendMessageMiddleware. This class itself is quite simple - the tricky part is the SendersLocatorInterface constructor argument, which normally Symfony handles creating for you. This is the concrete class that Symfony uses: https://github.com/symfony/symfony/blob/master/src/Symfony/Component/Messenger/Transport/Sender/SendersLocator.php

But, let's stop right there :). The full Symfony Framework Messenger is super feature rich and complex. And you may not need to hook up the same level of complexity and features in your legacy app. The simplest thing to do would be to create your own implementation of SendersLocatorInterface - it's a beautifully simple interface: https://github.com/symfony/symfony/blob/master/src/Symfony/Component/Messenger/Transport/Sender/SendersLocatorInterface.php

Inside, getSenders(), you could call $envelop->getMessage() and, if you want, just have a big map of which message class should go to which "SenderInterface". Or... maybe you only have one Sender/Transport. In that case, you could literally just return it:

public function getSenders(Envelope $envelope): iterable
{
    return [$this->myOneSender];
}

Let me know if that makes sense - or if there is something else tripping you up in this process :).

Cheers!