Sergey Zhuk has posted the third part of his series covering the creation of a Memcached client using ReactPHP has the base and allowing for asynchronous operations. In this latest part of the series (part three) he focuses on emitting events for various actions/results in the client code.
In the previous article, we have faced with a problem: how to deal with a broken connection. Now, when the connection is closed all pending requests are rejected with the ConnectionClosedException. If we want to handle this situation we need to attach onRejected handlers to all promises because we can’t guess in advance which one will be the problem.
This [example] code already looks too complex, but also there is no way to find out if the connection was broken or we have manually close it. So, it becomes clear that we need a completely different approach.
He then shows how to make use of this event library to emit events at certain points in the client's state. He includes code examples showing how to use the
emit method to throw the event focusing on handling when there's connection issues.