Module: ViewModel::ActiveRecord::AssociationManipulation

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 101

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
          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 direct_viewmodel_class._list_member?
          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 215

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
        # 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 6

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

  if direct_viewmodel._list_member?
    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) }

  if eager_include
    child_context = self.context_for_child(association_name, context: serialize_context)
    ViewModel.preload_for_serialization(vms, serialize_context: child_context)
  end

  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).



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# File 'lib/view_model/active_record/association_manipulation.rb', line 54

def replace_associated(association_name, update_hash, references: {}, deserialize_context: self.class.new_deserialize_context)
  association_data = self.class._association_data(association_name)

  if association_data.referenced?
    is_fupdate =
      association_data.collection? &&
      update_hash.is_a?(Hash) &&
      update_hash[ViewModel::ActiveRecord::TYPE_ATTRIBUTE] == ViewModel::ActiveRecord::FUNCTIONAL_UPDATE_TYPE

    if is_fupdate
      update_hash[ViewModel::ActiveRecord::ACTIONS_ATTRIBUTE].each_with_index do |action, i|
        action_type_name = action[ViewModel::ActiveRecord::TYPE_ATTRIBUTE]
        if action_type_name == ViewModel::ActiveRecord::FunctionalUpdate::Remove::NAME
          # Remove actions are always type/id refs; others need to be translated to proper refs
          next
        end

        association_references = convert_updates_to_references(
          action[ViewModel::ActiveRecord::VALUES_ATTRIBUTE],
          key: "#{action_type_name}_#{i}")
        references.merge!(association_references)
        action[ViewModel::ActiveRecord::VALUES_ATTRIBUTE] =
          association_references.each_key.map { |ref| { ViewModel::REFERENCE_ATTRIBUTE => ref } }
      end
    else
      update_hash = ViewModel::Utils.wrap_one_or_many(update_hash) do |sh|
        association_references = convert_updates_to_references(sh, key: 'replace')
        references.merge!(association_references)
        association_references.each_key.map { |ref| { ViewModel::REFERENCE_ATTRIBUTE => ref } }
      end
    end
  end

  root_update_hash = {
    ViewModel::ID_ATTRIBUTE   => self.id,
    ViewModel::TYPE_ATTRIBUTE => self.class.view_name,
    association_name.to_s     => update_hash,
  }

  root_update_viewmodel = self.class.deserialize_from_view(root_update_hash, references: references, deserialize_context: deserialize_context)

  root_update_viewmodel._read_association(association_name)
end