Class: MailyHerald::Context

Inherits:
Object
  • Object
show all
Defined in:
lib/maily_herald/context.rb

Overview

Abstraction layer for accessing collections of Entities and their attributes. Information provided by scope is used while sending mailings.

Context defines following:

  • Entity scope - ActiveRecord::Relation, list of Entities that will be returned by Context.

  • Entity model name - deducted automatically from scope.

  • Entity attributes - Defined as procs that can be evaluated for every item of the scope (single Entity).

  • Entity email - defined as proc or string/symbol (email method name).

Defined Under Namespace

Classes: Attributes, Drop

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(name) ⇒ Context

Creates MailyHerald::Context and sets its name.



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# File 'lib/maily_herald/context.rb', line 99

def initialize name
  @name = name
end

Instance Attribute Details

#destination(&block) ⇒ Object

Entity email address.

Can be eitner Proc or attribute name (string, symbol).

If block passed, it is saved as destination proc. Block has to:

  • accept single Entity object,
  • return Entity email.

If no block given, destination attribute is returned (a string, symbol or proc).



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# File 'lib/maily_herald/context.rb', line 132

def destination &block
  if block_given?
    @destination = block
  else
    @destination
  end
end

#name ⇒ Object (readonly)

Identification name of the MailyHerald::Context.

This can be then used in MailyHerald.context method to fetch the MailyHerald::Context.

See Also:



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# File 'lib/maily_herald/context.rb', line 94

def name
  @name
end

#title ⇒ Object

Friendly name of the MailyHerald::Context.

Displayed ie. in the Web UI.



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# File 'lib/maily_herald/context.rb', line 87

def title
  @title
end

Instance Method Details

#attributes(&block) ⇒ Object

Sepcify or return MailyHerald::Context attributes.

Defines Entity attributes that can be accessed using this Context. Attributes defined this way are then accesible in Liquid templates in Generic Mailer (Mailer#generic).

If block passed, it is used to create Context Attributes.

If no block given, current attributes are returned.



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# File 'lib/maily_herald/context.rb', line 202

def attributes &block
  if block_given?
    @attributes = Attributes.new block
  else
    @attributes
  end
end

#attributes_list ⇒ Object

Obtains MailyHerald::Context attributes in a form of (nested) Hash which values are procs each returning single Entity attribute value.



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# File 'lib/maily_herald/context.rb', line 212

def attributes_list
  return {} unless @attributes

  attributes = @attributes.dup
  attributes.setup 
  attributes.for_drop
end

#destination_attribute ⇒ Object

Returns Entity email attribute name only if it is not defined as a proc.



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# File 'lib/maily_herald/context.rb', line 141

def destination_attribute
  @destination unless @destination.respond_to?(:call)
end

#destination_for(entity) ⇒ Object

Fetches Entity's email address based on MailyHerald::Context destination definition.



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# File 'lib/maily_herald/context.rb', line 146

def destination_for entity
  destination_attribute ? entity.send(@destination) : @destination.call(entity)
end

#drop_for(entity, subscription) ⇒ Object

Returns Liquid drop created from Context attributes.



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# File 'lib/maily_herald/context.rb', line 221

def drop_for entity, subscription
  return {} unless @attributes

  attributes = @attributes.dup
  attributes.setup entity, subscription
  Drop.new(attributes.for_drop)
end

#model ⇒ Object

Fetches the Entity model class based on scope.



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# File 'lib/maily_herald/context.rb', line 118

def model
  @model ||= @scope.call.klass
end

#scope(&block) ⇒ Object

Defines or returns Entity scope - collection of Entities.

If block passed, it is saved as scope proc. Block has to return ActiveRecord::Relation containing entity objects that will belong to scope.

If no block given, scope proc is called and entity collection returned.



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# File 'lib/maily_herald/context.rb', line 109

def scope &block
  if block_given?
    @scope = block
  else
    @scope.call
  end
end

#scope_like(query) ⇒ ActiveRecord::Relation

Simply filter Entity scope by email.

If destination is provided in form of Entity attribute name (not the proc), this method creates the scope filtered by query email using SQL LIKE.

Parameters:

  • query (String) —

    email address which is being searched.

Returns:

  • (ActiveRecord::Relation) —

    collection filtered by email address



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# File 'lib/maily_herald/context.rb', line 157

def scope_like query
  if destination_attribute
    scope.where("#{model.table_name}.#{destination_attribute} LIKE (?)", "%#{query}%")
  end
end

#scope_with_subscription(list, mode = :inner) ⇒ Object

Returns Entity collection scope with joined Subscription.

Parameters:

  • list (List, Fixnum, String) —

    List reference

  • mode (:inner, :outer) (defaults to: :inner) —

    SQL JOIN mode



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# File 'lib/maily_herald/context.rb', line 167

def scope_with_subscription list, mode = :inner
  list_id = case list
            when List
              list.id
            when Fixnum
              list
            when String
              list.to_i
            else
              raise ArgumentError
            end

  join_mode = case mode
              when :outer
                "LEFT OUTER JOIN"
              else
                "INNER JOIN"
              end

  subscription_fields_select = Subscription.columns.collect{|c| "#{Subscription.table_name}.#{c.name} AS maily_subscription_#{c.name}"}.join(", ")

  scope.select("#{model.table_name}.*, #{subscription_fields_select}").joins(
    "#{join_mode} #{Subscription.table_name} ON #{Subscription.table_name}.entity_id = #{model.table_name}.id AND #{Subscription.table_name}.entity_type = '#{model.base_class.to_s}' AND #{Subscription.table_name}.list_id = '#{list_id}'"
  )
end