84 lines
3.7 KiB
Ruby
84 lines
3.7 KiB
Ruby
module ActionController #:nodoc:
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module Dependencies #:nodoc:
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def self.append_features(base)
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super
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base.extend(ClassMethods)
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end
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# Dependencies control what classes are needed for the controller to run its course. This is an alternative to doing explicit
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# +require+ statements that bring a number of benefits. It's more succinct, communicates what type of dependency we're talking about,
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# can trigger special behavior (as in the case of +observer+), and enables Rails to be clever about reloading in cached environments
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# like FCGI. Example:
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#
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# class ApplicationController < ActionController::Base
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# model :account, :company, :person, :project, :category
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# helper :access_control
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# service :notifications, :billings
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# observer :project_change_observer
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# end
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#
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# Please note that a controller like ApplicationController will automatically attempt to require_dependency on a model of its
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# singuralized name and a helper of its name. If nothing is found, no error is raised. This is especially useful for concrete
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# controllers like PostController:
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#
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# class PostController < ApplicationController
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# # model :post (already required)
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# # helper :post (already required)
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# end
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#
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# Also note, that if the models follow the pattern of just 1 class per file in the form of MyClass => my_class.rb, then these
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# classes don't have to be required as Active Support will auto-require them.
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module ClassMethods #:nodoc:
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# Specifies a variable number of models that this controller depends on. Models are normally Active Record classes or a similar
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# backend for modelling entity classes.
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def model(*models)
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require_dependencies(:model, models)
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depend_on(:model, models)
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end
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# Specifies a variable number of services that this controller depends on. Services are normally singletons or factories, like
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# Action Mailer service or a Payment Gateway service.
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def service(*services)
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require_dependencies(:service, services)
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depend_on(:service, services)
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end
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# Specifies a variable number of observers that are to govern when this controller is handling actions. The observers will
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# automatically have .instance called on them to make them active on assignment.
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def observer(*observers)
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require_dependencies(:observer, observers)
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depend_on(:observer, observers)
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instantiate_observers(observers)
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end
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# Returns an array of symbols that specify the dependencies on a given layer. For the example at the top, calling
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# <tt>ApplicationController.dependencies_on(:model)</tt> would return <tt>[:account, :company, :person, :project, :category]</tt>
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def dependencies_on(layer)
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read_inheritable_attribute("#{layer}_dependencies")
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end
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def depend_on(layer, dependencies) #:nodoc:
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write_inheritable_array("#{layer}_dependencies", dependencies)
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end
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private
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def instantiate_observers(observers)
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observers.flatten.each { |observer| Object.const_get(Inflector.classify(observer.to_s)).instance }
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end
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def require_dependencies(layer, dependencies)
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dependencies.flatten.each do |dependency|
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begin
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require_dependency(dependency.to_s)
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rescue LoadError => e
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raise LoadError.new("Missing #{layer} #{dependency}.rb").copy_blame!(e)
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rescue Object => exception
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exception.blame_file! "=> #{layer} #{dependency}.rb"
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raise
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end
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end
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end
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end
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end
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end
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