Class: Junkfood::Ceb::BaseCommand

Inherits:
Object
  • Object
show all
Includes:
Bus, Mongoid::Document
Defined in:
lib/junkfood/ceb/base_command.rb

Overview

BaseCommand abstract class from which one defines and implements actual Commands to be run.

  • _id - The mongodb id of the created Command.

  • _type - The type of the command. Based off subclass Name.

  • created_at - When the event was created/saved to mongodb.

  • origin - A descriptive string about where this command originated. For example, from the main web application or a separate web service api.

Example:

##
# This is a simple command that creates a blog post, which is backed
# by an ActiveRecord based model.
#
class Post::CreateCommand < Junkfood::Ceb::BaseCommand

  def perform
    # The constructor is set to be a Mongoid document constructor,
    # so all of the fields passed become dynamic attributes.
    # We access such attributes with the read_attribute method.
    #
    # The following example reads specific attributes to be passed
    # on to the actual Post model for creation.
    params = {
      'user_id' => read_attribute(:author_id),
      'title' => read_attribute(:title),
      'body' => read_attribute(:body),
    }
    post = Post.new(params)
    # The BaseCommand object is an event_bus, so we can
    # use it to send off events... then return the sent event.
    if post.save
      event, result = send_event :post_created, post
    else
      event, result = send_event :post_failed, post
    end
    return event
  end
end

Instance Method Summary collapse

Instance Method Details

#perform ⇒ Object

This method is abstract.

implement the actual handler logic to execute the command.



84
85
 
# File 'lib/junkfood/ceb/base_command.rb', line 84

def perform
end