Class: Fragmentary::Subscriber

Inherits:
Object
  • Object
show all
Defined in:
lib/fragmentary/subscriber.rb

Overview

Each fragment subclass has a unique Subscriber instance responsible for handling subscriptions to publishers. The subscriber is instantiated the first time it is referenced within the subscribe_to method called on the fragment. That method calls a method of the same name on the subscriber, which instantiates a new Subscription for each publisher it subscribes to and executes its block against the subscriber, thus defining handlers for each publisher event of interest on the subscriber, (rather than the fragment). Any other method invoked within a handler is delegated to the client, i.e. the Fragment subclass that the subscriber is responsible for.

A separate subscription exists for each combination of publisher and subscriber (and thus Fragment subclass). When a subscription is instantiated for a given publisher, it registers itself with a Subscription::Proxy for that publisher. The proxy, is instantiated the first time it is referenced by a subscription to a particular publisher, and it subscribes on behalf of all its registered subscriptions to Wisper events broadcast by that publisher.

The Proxy class contains the methods such as 'after_create', 'after_update' etc that are called automatically by Wisper when the publisher broacdcasts the corresponding events. These methods each invoke methods of the same name on each of proxy's registered subscriptions, and it is these that in turn invoke the methods defined by the subscribe_to blocks on the susbcriber associated with the subscription.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(client) ⇒ Subscriber

Returns a new instance of Subscriber.



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# File 'lib/fragmentary/subscriber.rb', line 26

def initialize(client)
  @client = client
  @subscriptions = Hash.new do |h, key|
    publisher = key.constantize  # Ensures that the model is loaded so that the const below is defined.
    if Object.const_defined?(key) and publisher < ActiveRecord::Base
      h[key] = Subscription.new(publisher, self)
    else
      nil
    end
  end
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(method, *args) ⇒ Object 



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# File 'lib/fragmentary/subscriber.rb', line 46

def method_missing(method, *args)
  @client.send(method, *args)
end

Instance Attribute Details

#client ⇒ Object (readonly)

Returns the value of attribute client.



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# File 'lib/fragmentary/subscriber.rb', line 24

def client
  @client
end

#subscriptions ⇒ Object (readonly)

Returns the value of attribute subscriptions.



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# File 'lib/fragmentary/subscriber.rb', line 24

def subscriptions
  @subscriptions
end

Instance Method Details

#subscribe_to(publisher, block) ⇒ Object 



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# File 'lib/fragmentary/subscriber.rb', line 38

def subscribe_to(publisher, block)
  if subscriptions[publisher.name]
    mod = Module.new
    mod.module_exec(&block)
    self.extend mod
  end
end