roda-container
A plugin for Roda which turns your application into a (IoC) container
Installation
gem 'roda-container', '0.0.3'
Usage
class MyApplication < Roda
plugin :container
end
class UserRepository
def self.first
{ name: 'Jack' }
end
end
MyApplication.register(:user_repository, UserRepository)
MyApplication.resolve(:user_repository).first
# => {:name=>"Jack"}
class PersonRepository
def first
{ name: 'Gill' }
end
end
MyApplication.register(:person_repository, -> { PersonRepository.new })
MyApplication.resolve(:person_repository).first
# => {:name=>"Gill"}
If you want to register a proc, or anything that responds to call, without calling when resolving it, you can pass the call: false option:
class MyApplication < Roda
plugin :container
end
MyApplication.route do |r|
# Roda responds to the instance method #call, with the call: false
# option, calling MyApplication.instance.resolve(:app) will not attempt to call
# it, without the option, the application would error
MyApplication.instance.register(:app, self, call: false)
end
Thread safety
Please note the use of MyApplication.instance.register and MyApplication.instance.resolve above, without the calls to Roda.instance there is a high possiblilty of a thread safety issue when registering anything at runtime. For example:
class MyApplication < Roda
plugin :container
end
MyApplication.route do |r|
# DO NOT DO THIS, SEE ABOVE ^^^
MyApplication.register(:app, self, call: false)
r.on 'users' do
# ...
r.get :id do |user_id|
MyApplication.resolve(:app)
end
r.post do
sleep(5)
MyApplication.resolve(:app)
end
end
end
Immagine a user hitting POST /users, then another user hitting GET /users/{id} in quick succession; the first user registers their instance of app with the container, then hits the 5 second sleep, then the second user comes along, registers their instance of app with the container, the request executes and they go on their merry way.
A few seconds later the 5 second sleep is complete, and the first user resolves :app from the container, only to find the instance that was registered by the user hitting GET /users/{id}, they have just spent 5 minutes meticulously filling out your webform to create their user account, only for their payload to lost in a race condition, needless to say, you don't want this to happen.
Contributing
- Fork it ( https://github.com/AMHOL/roda-container )
- Create your feature branch (
git checkout -b my-new-feature) - Commit your changes (
git commit -am 'Add some feature') - Push to the branch (
git push origin my-new-feature) - Create a new Pull Request