Does dependency injection exist in Rails?
Ruby on-RailsRubySpringDependency InjectionRuby on-Rails Problem Overview
Does the fact that Rails have an MVC approach mean that is has dependency injection?
Or is there a reason that we don't talk about dependency injection in Rails?
If Rails does have dependency injection, what does it consist of?
Ruby on-Rails Solutions
Solution 1 - Ruby on-Rails
IoC is the big hammer, but DI happens everyday in Ruby / Rails. Whenever you do:
def initialize(model_klass)
@model_klass = model_klass
end
This is DI. This paradigm is also used in various places in Rails source code. For example, the Railties gem itself is mostly a DI Engine. You can inject your favoriate ORM, various plugin configs, and generators.
Dependency Injection has a big and scary name, but what it boils down to is just decoupling class dependencies by ways of injecting the dependencies during runtime.
It doesn't matter what language you use, as long as you need to plug behavior / code in somewhere, you are probably using it.
Solution 2 - Ruby on-Rails
Dependency Injection is a paradigm, so it exists in every object-oriented language.
Whether there are DI frameworks for Ruby - check https://stackoverflow.com/questions/283466/ruby-dependency-injection-libraries">this question
Solution 3 - Ruby on-Rails
I'd say that you don't need such a thing with ruby... but if you really want to, some people have workarounds.
Solution 4 - Ruby on-Rails
I use this IoC https://github.com/alexeypetrushin/micon in my Web Framework, most of time it stays hidden and silently solves issues of dependencies and component initializtion that otherwise should be solved manually.
You can see it in action here http://ruby-lang.info (this site powered with Rad, my web framework https://github.com/alexeypetrushin/rad_core ).
Solution 5 - Ruby on-Rails
Dependency injection is usually unnecessary with Ruby. Jamis Buck blogged extensively about the reasons why. Well worth a read.