Module: Streamit::DSL::ClassMethods

Defined in:
lib/streamit/dsl.rb

Overview

A class method for ActiveRecord models

Sample usage:

stream :create, :actor => :watcher,

:receiver => :item

stream :update, :attributes => :image_url,

Instance Method Summary collapse

Instance Method Details

#stream(action, options = {}) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/streamit/dsl.rb', line 15

def stream(action, options={})
  options.assert_valid_keys(:actor, :subject, :receiver, :attributes)
  raise ArgumentError, ":create or :update required as first parameter" \
    unless [:create, :update].any? {|sym| sym == action }
  
  table_name = self.model_name.downcase.pluralize
  attributes = options[:attributes]
  
  attr_name = if action == :update
    case attributes
    when Array, nil
      :default
    when Symbol
      attributes
    end
  end
  
  stream_type = attr_name.nil? ? "streamit.#{table_name}.#{action}" :
                                 "streamit.#{table_name}.#{action}.#{attr_name}"
                                 
  method_name = :"_#{stream_type.gsub('.', '_')}"
  
  define_method(method_name) do
    stream_options = [:actor, :receiver, :subject].inject({}) do |memo, sym|
      memo[sym] = options[sym] ? send(options[sym]) : (sym == :actor ? self : nil)
      memo
    end.merge(:stream_type => stream_type, :started_at => Time.now)

    if (action != :update || instance_variable_get("@attr_changed"))
      Streamit.save_stream!(stream_options)
    end
      
    instance_variable_set("@attr_changed", false)
  end
  
  if action == :update
    before_update_method_name = "_before#{method_name}"
    define_method(before_update_method_name) do
      attr_changed = if action == :update
        case attributes
        when nil
          changed?
        when Array
          attributes.any? { |attr| send(:"#{attr}_changed?") }
        when Symbol
          send(:"#{attributes}_changed?")
        end
      end
      instance_variable_set("@attr_changed", attr_changed)
    end
    send(:"before_update", before_update_method_name)
  end
  
  send(:"after_#{action}", method_name)
end