client VS msgpack.php

That was an example of a simple UUID extension. Similarly, you can add support for any other type used in your application: DateTime, Decimal, Money. Or you can write a versatile extension that allows serializing any object (as it was done in KPHP). However, this is not the only use for extensions. I'll now show you some interesting examples that demonstrate other advantages of using extension types.

That's enough theory, let's start coding! For these examples, we'll use the msgpack.php MessagePack library since it provides a convenient API to handle extension types. I hope you'll find these code examples easy to understand even if you use other libraries. Since I mentioned UUID, let's implement support for this data type as an example. To do so, we'll need to write an extension---a class to serialize and deserialize UUID values. We will use the symfony/uid library to make handling such values easier.

I recently encountered an interesting case. I was trying to optimize the MessagePack unpacking, but after testing the performance of the new faster (as I thought) version, it turned out to be slower than the original implementation. Trying to figure out which part of the code was causing the slowdown, I reran the tests with Blackfire and was surprised to see that the profiler reported a 30% improvement in the new version, which was the exact opposite of my results (read the comments on the linked issue to learn why). Note that this is not a problem with this particular profiler, most PHP profilers will do the same. So I decided to share this finding and encourage you not to blindly trust profilers and always do your own benchmarking, especially when you do such micro-optimizations.