Module: ViewModel::ActiveRecord::AssociationManipulation

Extended by:
ActiveSupport::Concern
Included in:
ViewModel::ActiveRecord
Defined in:
lib/view_model/active_record/association_manipulation.rb

Overview

Mix-in for VM::ActiveRecord providing direct manipulation of directly-associated entities. Avoids loading entire collections.

Instance Method Summary collapse

Instance Method Details

#append_associated(association_name, subtree_hash_or_hashes, references: {}, before: nil, after: nil, deserialize_context: self.class.new_deserialize_context) ⇒ Object

Create or update members of a associated collection. For an ordered collection, the items are inserted either before ‘before`, after `after`, or at the end.

Raises:

  • (ArgumentError) 


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# File 'lib/view_model/active_record/association_manipulation.rb', line 116

def append_associated(association_name, subtree_hash_or_hashes, references: {}, before: nil, after: nil, deserialize_context: self.class.new_deserialize_context)
  if self.changes.changed?
    raise ArgumentError.new('Invalid call to append_associated on viewmodel with pending changes')
  end

  association_data = self.class._association_data(association_name)
  direct_reflection = association_data.direct_reflection
  raise ArgumentError.new("Cannot append to single association '#{association_name}'") unless association_data.collection?

  ViewModel::Utils.wrap_one_or_many(subtree_hash_or_hashes) do |subtree_hashes|
    model_class.transaction do
      ViewModel::Callbacks.wrap_deserialize(self, deserialize_context: deserialize_context) do |hook_control|
        association_changed!(association_name)
        deserialize_context.run_callback(ViewModel::Callbacks::Hook::BeforeValidate, self)

        if association_data.through?
          raise ArgumentError.new('Polymorphic through relationships not supported yet') if association_data.polymorphic?

          direct_viewmodel_class = association_data.direct_viewmodel
          root_update_data, referenced_update_data = construct_indirect_append_updates(association_data, subtree_hashes, references)
        else
          raise ArgumentError.new('Polymorphic STI relationships not supported yet') if association_data.polymorphic?

          direct_viewmodel_class = association_data.viewmodel_class
          root_update_data, referenced_update_data = construct_direct_append_updates(association_data, subtree_hashes, references)
        end

        update_context = ViewModel::ActiveRecord::UpdateContext.build!(root_update_data, referenced_update_data, root_type: direct_viewmodel_class)

        # Set new parent
        new_parent = ViewModel::ActiveRecord::UpdateOperation::ParentData.new(direct_reflection.inverse_of, self)
        update_context.root_updates.each { |update| update.reparent_to = new_parent }

        # Set place in list.
        if association_data.ordered?
          new_positions = select_append_positions(association_data,
                                                  direct_viewmodel_class._list_attribute_name,
                                                  update_context.root_updates.count,
                                                  before: before, after: after)

          update_context.root_updates.zip(new_positions).each do |update, new_pos|
            update.reposition_to = new_pos
          end
        end

        # Because append_associated can take from other parents, edit-check previous parents (other than this model)
        unless association_data.through?
          inverse_assoc_name = direct_reflection.inverse_of.name

          previous_parent_ids = Set.new
          update_context.root_updates.each do |update|
            update_model    = update.viewmodel.model
            parent_model_id = update_model.read_attribute(update_model
                                                            .association(inverse_assoc_name)
                                                            .reflection.foreign_key)

            if parent_model_id && parent_model_id != self.id
              previous_parent_ids << parent_model_id
            end
          end

          if previous_parent_ids.present?
            previous_parents = self.class.find(previous_parent_ids.to_a, eager_include: false)

            previous_parents.each do |parent_view|
              ViewModel::Callbacks.wrap_deserialize(parent_view, deserialize_context: deserialize_context) do |pp_hook_control|
                changes = ViewModel::Changes.new(changed_associations: [association_name])
                deserialize_context.run_callback(ViewModel::Callbacks::Hook::OnChange, parent_view, changes: changes)
                pp_hook_control.record_changes(changes)
              end
            end
          end
        end

        child_context = self.context_for_child(association_name, context: deserialize_context)
        updated_viewmodels = update_context.run!(deserialize_context: child_context)

        # Propagate changes and finalize the parent
        updated_viewmodels.each do |child|
          child_changes = child.previous_changes

          if association_data.nested?
            nested_children_changed!     if child_changes.changed_nested_tree?
            referenced_children_changed! if child_changes.changed_referenced_children?
          elsif association_data.owned?
            referenced_children_changed! if child_changes.changed_owned_tree?
          end
        end

        final_changes = self.clear_changes!

        if association_data.through?
          updated_viewmodels.map! do |direct_vm|
            direct_vm._read_association(association_data.indirect_reflection.name)
          end
        end

        # Could happen if hooks attempted to change the parent, which aren't
        # valid since we're only editing children here.
        unless final_changes.contained_to?(associations: [association_name.to_s])
          raise ViewModel::DeserializationError::InvalidParentEdit.new(final_changes, blame_reference)
        end

        deserialize_context.run_callback(ViewModel::Callbacks::Hook::OnChange, self, changes: final_changes)
        hook_control.record_changes(final_changes)

        updated_viewmodels
      end
    end
  end
end

#delete_associated(association_name, associated_id, type: nil, deserialize_context: self.class.new_deserialize_context) ⇒ Object

Removes the association between the models represented by this viewmodel and the provided associated viewmodel. The associated model will be garbage-collected if the assocation is specified with ‘dependent: :destroy` or `:delete_all`



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# File 'lib/view_model/active_record/association_manipulation.rb', line 232

def delete_associated(association_name, associated_id, type: nil, deserialize_context: self.class.new_deserialize_context)
  if self.changes.changed?
    raise ArgumentError.new('Invalid call to delete_associated on viewmodel with pending changes')
  end

  association_data = self.class._association_data(association_name)
  direct_reflection = association_data.direct_reflection

  unless association_data.collection?
    raise ArgumentError.new("Cannot remove element from single association '#{association_name}'")
  end

  check_association_type!(association_data, type)
  target_ref = ViewModel::Reference.new(type || association_data.viewmodel_class, associated_id)

  model_class.transaction do
    ViewModel::Callbacks.wrap_deserialize(self, deserialize_context: deserialize_context) do |hook_control|
      association_changed!(association_name)
      deserialize_context.run_callback(ViewModel::Callbacks::Hook::BeforeValidate, self)

      association = self.model.association(direct_reflection.name)
      association_scope = association.scope

      if association_data.through?
        raise ArgumentError.new('Polymorphic through relationships not supported yet') if association_data.polymorphic?

        direct_viewmodel = association_data.direct_viewmodel
        association_scope = association_scope.where(association_data.indirect_reflection.foreign_key => associated_id)
      else
        raise ArgumentError.new('Polymorphic STI relationships not supported yet') if association_data.polymorphic?

        # viewmodel type for current association: nil in case of empty polymorphic association
        direct_viewmodel = association.klass.try { |k| association_data.viewmodel_class_for_model!(k) }

        if association_data.pointer_location == :local
          # If we hold the pointer, we can immediately check if the type and id match.
          if target_ref != ViewModel::Reference.new(direct_viewmodel, model.read_attribute(direct_reflection.foreign_key))
            raise ViewModel::DeserializationError::AssociatedNotFound.new(association_name.to_s, target_ref, blame_reference)
          end
        else
          # otherwise add the target constraint to the association scope
          association_scope = association_scope.where(id: associated_id)
        end
      end

      models = association_scope.to_a

      if models.blank?
        raise ViewModel::DeserializationError::AssociatedNotFound.new(association_name.to_s, target_ref, blame_reference)
      elsif models.size > 1
        raise ViewModel::DeserializationError::Internal.new(
                "Internal error: encountered multiple records for #{target_ref} in association #{association_name}",
                blame_reference)
      end

      child_context = self.context_for_child(association_name, context: deserialize_context)
      child_vm = direct_viewmodel.new(models.first)

      ViewModel::Callbacks.wrap_deserialize(child_vm, deserialize_context: child_context) do |child_hook_control|
        changes = ViewModel::Changes.new(deleted: true)
        child_context.run_callback(ViewModel::Callbacks::Hook::OnChange, child_vm, changes: changes)
        child_hook_control.record_changes(changes)

        association.delete(child_vm.model)
      end

      if association_data.nested?
        nested_children_changed!
      elsif association_data.owned?
        referenced_children_changed!
      end

      final_changes = self.clear_changes!

      unless final_changes.contained_to?(associations: [association_name.to_s])
        raise ViewModel::DeserializationError::InvalidParentEdit.new(final_changes, blame_reference)
      end

      deserialize_context.run_callback(ViewModel::Callbacks::Hook::OnChange, self, changes: final_changes)
      hook_control.record_changes(final_changes)

      child_vm
    end
  end
end

#load_associated(association_name, scope: nil, eager_include: true, serialize_context: self.class.new_serialize_context) ⇒ Object 



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# File 'lib/view_model/active_record/association_manipulation.rb', line 8

def load_associated(association_name, scope: nil, eager_include: true, serialize_context: self.class.new_serialize_context)
  association_data = self.class._association_data(association_name)
  direct_reflection = association_data.direct_reflection

  association = self.model.association(direct_reflection.name)
  association_scope = association.scope

  if association_data.through?
    raise ArgumentError.new('Polymorphic through relationships not supported yet') if association_data.polymorphic?

    associated_viewmodel = association_data.viewmodel_class
    direct_viewmodel     = association_data.direct_viewmodel
  else
    raise ArgumentError.new('Polymorphic STI relationships not supported yet') if association_data.polymorphic?

    associated_viewmodel = association.klass.try { |k| association_data.viewmodel_class_for_model!(k) }
    direct_viewmodel     = associated_viewmodel
  end

  if association_data.ordered?
    association_scope = association_scope.order(direct_viewmodel._list_attribute_name)
  end

  if association_data.through?
    association_scope = associated_viewmodel.model_class
                          .joins(association_data.indirect_reflection.inverse_of.name)
                          .merge(association_scope)
  end

  association_scope = association_scope.merge(scope) if scope

  vms = association_scope.map { |model| associated_viewmodel.new(model) }

  ViewModel.preload_for_serialization(vms) if eager_include

  if association_data.collection?
    vms
  else
    if vms.size > 1
      raise ViewModel::DeserializationError::Internal.new("Internal error: encountered multiple records for single association #{association_name}", self.blame_reference)
    end

    vms.first
  end
end

#replace_associated(association_name, update_hash, references: {}, deserialize_context: self.class.new_deserialize_context) ⇒ Object

Replace the current member(s) of an association with the provided hash(es). Only mentioned member(s) will be returned.

This interface deals with associations directly where reasonable, with the notable exception of referenced+shared associations. That is to say, that owned associations should be presented in the form of direct update hashes, regardless of their referencing. Reference and shared associations are excluded to ensure that the update hash for a shared entity is unique, and that edits may only be specified once.



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# File 'lib/view_model/active_record/association_manipulation.rb', line 64

def replace_associated(association_name, update_hash, references: {}, deserialize_context: self.class.new_deserialize_context)
  _updated_parent, changed_children =
    self.class.replace_associated_bulk(
      association_name,
      { self.id => update_hash },
      references: references,
      deserialize_context: deserialize_context
    ).first

  changed_children
end