Views

Blueprints can define views to provide different representations of the data. A view inherits everything from its parent but is free to override as needed. In addition to fields, views can define options, partials, formatters, extensions, and nested views.

class WidgetBlueprint < ApplicationBlueprint
  field :name
  object :category, CategoryBlueprint

  # The "with_parts" view inherits from "default" and adds a collection of parts
  view :with_parts do
    collection :parts, PartBlueprint
  end

  # Views can include other views
  view :full do
    use :with_parts
    field :description
  end
end

At the top level of every Blueprint is an implicit view called default. The default view is used when no other is specified. All other views in the Blueprint inherit from it.

Nesting views

You can nest views within views, allowing for a hierarchy of inheritance.

class WidgetBlueprint < ApplicationBlueprint
  field :name
  object :category, CategoryBlueprint

  view :extended do
    field :description
    collection :parts, PartBlueprint

    # The "extended.with_price" view adds a price field
    view :with_price do
      field :price
    end
  end

Excluding fields

Views can exclude select fields from parents, views they’ve included, or from partials.

class WidgetBlueprint < ApplicationBlueprint
  fields :name, :description, :price

  view :minimal do
    exclude :description, :price
  end
end

You can exclude and and all parent fields by creating an empty view:

class WidgetBlueprint < ApplicationBlueprint
  fields :name, :description, :price

  view :minimal, empty: true do
    field :the_only_field
  end
end

Referencing views

When defining an association, you can choose a view from its blueprint:

object :widget, WidgetBlueprint[:extended]

Nested views can be accessed with a dot syntax or a nested Hash syntax.

collection :widgets, WidgetBlueprint["extended.with_price"]
collection :widgets, WidgetBlueprint[:extended][:with_price]

Inheriting from views

You can inherit from another blueprint, or from one of its views:

class WidgetBlueprint < ApplicationBlueprint[:with_timestamps]
  # ...
end