Dependency Injection in the upcoming Symfony 2.0
(I’ve previously written a post where I tried to take Martin Fowler’s essay and change some of the examples into PHP.)
Fabien Potencier writes:
During the first five articles of this series on Dependency Injection, we have progressively introduced the main concepts behind this simple and useful design pattern. We have also talked about the implementation of a lightweight PHP container that will be used for Symfony 2.
This looks like a series worth reading, especially as a glimpse of the future of Symfony:
- Part 1: What is Dependency Injection?
- Part 2: Do you need a Dependency Injection Container?
- Part 3: Introduction to the Symfony Service Container
- Part 4: Symfony Service Container: Using a Builder to create Services
- Part 5: Symfony Service Container: Using XML or YAML to describe Services
- Part 6: The Need for Speed
When creating software, you can get the greatest performance speed by getting rid of any framework and writing arbitrary, ad-hoc code that suits the particular problem you face today. But, of course, such code quickly becomes an unmanageable nightmare, which is why so many of us use a framework. But frameworks are slow. Having a formal system of dependency injection adds another layer of abstraction, providing greater flexibility, but even worse performance. Given that traditional trade-off, this sounds absolutely amazing:
How can you have the best of both world? That’s quite simply. The Symfony Dependency Injection component provides yet another built-in dumper: a PHP dumper. This dumper can convert any service container to plain PHP code. That’s right, it is able to generate the code you could have written by hand in the first place.