JSON with full hierarchy in Rails - ruby-on-rails

Question

I have an hierarchical structure in my app:
Environment has Containers
Container has Items
Item has expression
so my Model code looks like:
class Environment < ActiveRecord::Base
has_many :containers, :dependent => :destroy
def as_json(options = {})
super(options.merge(include: :containers))
end
end
class Container < ActiveRecord::Base
has_many :items, :dependent => :destroy
belongs_to :environment
def as_json(options = {})
super(options.merge(include: :items))
end
end
class Item < ActiveRecord::Base
has_many :expressions, :dependent => :destroy
belongs_to :container
def as_json(options = {})
super(options.merge(include: :expressions))
end
end
class Expression < ActiveRecord::Base
belongs_to :item
def as_json(options = {})
super()
end
end
In a regular get of a record I usually need only one hierarchy below the desired record, that's why in the as_json I merge only one hierarchy down (get Environment will return a collection of containers but those containers will not have Items)
My Question:
Now what I need is to add a method to the controller that allows full hierarchy response i.e. GET /environment/getFullHierarchy/3 will return: environment with id=3 with all its containers and for every container all it's Items & for every Item all it's expressions. without breaking the current as_json
I'm kinda new to Rails, wirking with Rails 4.2.6 & don't know where to start - can anyone help?

Answer 1

Sure it goes something like this hopefully you get the idea.
EnvironmentSerializer.new(environment) to get the hierarchy json.
lets say environments table has columns environment_attr1 , environment_attr2
class EnvironmentSerializer < ActiveModel::Serializer
attributes :environment_attr1, :environment_attr2 , :containers
# This method is called if you have defined a
# attribute above which is not a direct value like for
# a rectancle serializer will have attributes length and width
# but you can add a attribute area as a symbol and define a method
# area which returns object.length * object.width
def containers
ActiveModel::ArraySerializer.new(object.containers,
each_serializer: ContainerSerializer)
end
end
class ContainerSerializer < ActiveModel::Serializer
attributes :container_attr1, :container_attr2 , :items
def items
ActiveModel::ArraySerializer.new(object.items,
each_serializer: ItemSerializer)
end
end
class ItemSerializer < ActiveModel::Serializer
...
end
class ExpressionSerializer < ActiveModel::Serializer
...
end