Class: Babik::Association::ForeignAssociationChain

Inherits:
Object
  • Object
show all
Defined in:
lib/babik/queryset/lib/association/foreign_association_chain.rb

Overview

Association chain for association paths An association chain is a chain of associations where the target model of association i is the origin model of association i + 1 Remember, an association path is of the form: zone::parent_zone, category::posts::tags

Direct Known Subclasses

SelectRelatedAssociationChain

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(model, association_path, selection_path) ⇒ ForeignAssociationChain

Construct the association chain

Parameters:

  • model (ActiveRecord::Base) —

    origin model

  • association_path (Array) —

    association path as an array.

  • selection_path (String, Symbol) —

    selection path used only to raise errors.



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# File 'lib/babik/queryset/lib/association/foreign_association_chain.rb', line 18

def initialize(model, association_path, selection_path)
  @model = model
  @association_path = association_path
  @selection_path = selection_path
  _init_associations
end

Instance Attribute Details

#associations ⇒ Object (readonly)

Returns the value of attribute associations.



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# File 'lib/babik/queryset/lib/association/foreign_association_chain.rb', line 12

def associations
  @associations
end

#model ⇒ Object (readonly)

Returns the value of attribute model.



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# File 'lib/babik/queryset/lib/association/foreign_association_chain.rb', line 12

def model
  @model
end

#selection_path ⇒ Object (readonly)

Returns the value of attribute selection_path.



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# File 'lib/babik/queryset/lib/association/foreign_association_chain.rb', line 12

def selection_path
  @selection_path
end

#target_model ⇒ Object (readonly)

Returns the value of attribute target_model.



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# File 'lib/babik/queryset/lib/association/foreign_association_chain.rb', line 12

def target_model
  @target_model
end

Instance Method Details

#_assert_association(association_model, association_name) ⇒ Association

Return an association or raise an exception if is not an allowed association

Returns:



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# File 'lib/babik/queryset/lib/association/foreign_association_chain.rb', line 76

def _assert_association(association_model, association_name)
  association = association_model.reflect_on_association(association_name.to_sym)

  # Check the association exists
  unless association
    raise "Bad selection path: #{@selection_path}. #{association_name} not found "\
          "in model #{association_model} when filtering #{@model} objects"
  end

  # Check the association is no a has-and belongs-to-many
  # These associations are discouraged by Rails Community
  if association.class == ActiveRecord::Reflection::HasAndBelongsToManyReflection
    raise "Relationship #{association.name} is has_and_belongs_to_many. Convert it to has_many-through"
  end

  # Valid association
  association
end

#_association_pass(association_i) ⇒ ActiveRecord::Base

Each one of the asssociation

Parameters:

  • association_i (AssociationReflection) —

    ith association.

Returns:

  • (ActiveRecord::Base) —

    target model of ith association.



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# File 'lib/babik/queryset/lib/association/foreign_association_chain.rb', line 47

def _association_pass(association_i)
  # To one relationship
  if association_i.belongs_to? || association_i.has_one?
    @associations << association_i
    return association_i.klass
  end

  # Many-to-many with through relationship
  # The has-and-belongs-to-many relationships have been detected and filtered in _construct_association

  # Add model-through association (active_record -> klass)
  if association_i.through_reflection
    @associations << association_i.through_reflection
    # Add through-target association (through -> target)
    target_name = association_i.source_reflection_name
    through_model = association_i.through_reflection.klass
    through_target_association = through_model.reflect_on_association(target_name)
    @associations << through_target_association
    # The next association comes from target model
    return through_target_association.klass
  end

  # Add direct has_many association
  @associations << association_i
  Object.const_get(association_i.class_name)
end

#_init_association(model, association_name) ⇒ ActiveRecord::Base

Initialize association by name

Parameters:

  • model (ActiveRecord::Base) —

    origin model of the association association_name

  • association_name (String, Symbol) —

    association name.

Returns:

  • (ActiveRecord::Base) —

    target model of ith association.



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# File 'lib/babik/queryset/lib/association/foreign_association_chain.rb', line 39

def _init_association(model, association_name)
  association = _assert_association(model, association_name)
  _association_pass(association)
end

#_init_associations ⇒ Object

Init associations



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# File 'lib/babik/queryset/lib/association/foreign_association_chain.rb', line 26

def _init_associations
  @associations = []
  associated_model_i = @model
  @association_path.each do |association_i_name|
    associated_model_i = _init_association(associated_model_i, association_i_name)
  end
  @target_model = associated_model_i
end