Pimple for Ruby

This is the Ruby implementation of Pimple, originally a leightweight Dependancy Injection library written in PHP and created by Fabien Potencier.

Refer to the original documentation for more details about Pimple, you could found better explanations on the topic.

Installation

Install with RubyGems :

sudo gem install pimple

Then, create the container :

require 'pimple'
container = Pimple.new

Defining parameter

container[:foo] = 'bar'
container[:foo] # => bar

Defining services

Pimple is built to provide services on demand. Just wrap a return instance to pimple in a lambda and get your service later when you need its functionnalities.

See that example to inject a redis client with some parameters:

# Defining redis config in container as parameter before ...
container[:redis_config] = {:host => 'localhost', :port => 6379}

# Defining the redis client into Pimple
container[:redis] = lambda { |c| Redis.new(c[:redis_config]) }

# And get an instance
container[:redis] # => #<Redis client v2.1.1 connected to redis://localhost:6379/0 (Redis v2.2.2)>

Important! : Each time you get a service by its key, Pimple will call your defined lambda and then return a new instance.

Defining shared services (Singleton like)

Sometimes, you need to work with the same instance each time you access to your service. Use share method as shown as below :

container[:session_storage] = container.share { Redis.new }

Defining protected parameter (Wrap anonymous function as parameter)

Anonymous functions (lambda) can be passed to the container to provide a method that make something. To ensure the lambda will be not evaluated as a service, you need to use protect method. Then, when you get the value from the container, you just have to to access the container value to automatically call the function. Let me show you an example with a random function :

# First of all, we inject the random function
container[:random] = container.protect { rand(100) }

# ... and sometime in the future, we want a random number.
# So we call the function from the container by its key
container[:random] # => 12
# ... and get another one later !
container[:random] # => 48

Extend services

Not implemented

Contribute <3

I'm sure this library can be improved by many ways. If you want to improve some stuff, feel free to send a pull-request with your changes. One condition, ensure to test and document your code ;).

fmhun/ruby-pimple