Class: Hyrax::Actors::AbstractActor

Inherits:
Object
  • Object
show all
Defined in:
app/actors/hyrax/actors/abstract_actor.rb

Overview

Hyrax::Actors::AbstractActor implements the base (no-op) case for Hyrax Actor middleware. Concrete implementations may override any or all of the three primary actions:

  • #create
  • #update
  • #destroy

Each of these should accept a Hyrax::Actor::Environment and return true to communicate to middleware further up the stack that execution below this point may be regarded as successful, and false to indicate that it has not. In the general case, returning false will pop out of the stack--though middleware further up may perform actions or even return true in response.

The next_actor attribute represents the actor immediately down in the stack from the current actor. This variable should be set as an argument to the initializer, but implementations may behave differently, e.g. to insert an actor into the stack at runtime.

In order to continue the stack actors must instantiate the next actor in the chain and call the corresponding action method.

Examples:

A simple actor that does work on create

class SimpleActor < AbstractActor
  def create(env)
    # act! is contingent on `next_actor` reporting success
    next_actor.create(env) && act!(env.curation_concern)
  end

  ##
  # @param work [Hyrax::Work]
  # @return [Boolean] truthy if the work succeeds
  def act!(work)
    # do some things with work here
    true
  end
end

A complex actor that you probably don't want to write.

class ComplexActor < AbstractActor
  def create(env)
    manipulate_env!(env)
    before! # do this regardless of what happens lower in the stack

    result = next_actor.create(env) # invoke the next actor

    # do after! only if next_actor reported a healthy state, set result
    # to reflect this actor's output.
    result && (result = after!)

    ensure! # do this after next_actor, even in the failure case

    result
  end
  # ...
end

Using an actor with an ActionDispatch stack

class MyMiddleware < AbstractActor
end

stack = ActionDispatch::MiddlewareStack.new.tap do |middleware|
  # middleware.use OtherMiddleware
  middleware.use MyActor
  # middleware.use MoreMiddleware
end

env = Hyrax::Actors::Environment.new(object, ability, attributes)
last_actor = Hyrax::Actors::Terminator.new

stack.build(last_actor).create(env) # or `#update/#destroy`

See Also:

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(next_actor) ⇒ AbstractActor

Returns a new instance of AbstractActor.

Parameters:



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# File 'app/actors/hyrax/actors/abstract_actor.rb', line 88

def initialize(next_actor)
  @next_actor = next_actor
end

Instance Attribute Details

#next_actor ⇒ Object (readonly)

Returns the value of attribute next_actor.



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# File 'app/actors/hyrax/actors/abstract_actor.rb', line 84

def next_actor
  @next_actor
end