Breaking DSL Changes

At a quick glance the DSL looks nearly identical, but don’t be fooled! See the docs of Blueprinter::V2::DSL for complete documentation of all new features.

Association syntax

Associations in V2 are more concise while conveying more information.

# A single object
association :category, CategoryBlueprint
association :category, CategoryBlueprint[:my_view]

# A collection (Enumerable) of objects
association :parts, [PartBlueprint]
association :parts, [PartBlueprint[:my_view]]

To dynamically reference the current view’s name, use view_name or view_path:

view :extended do
  # ...

  view :plus do
    # Looks for a view named 'plus'
    association :category, CategoryBlueprint[view_name]

    # Looks for a nested view named 'extended.plus'
    association :category, CategoryBlueprint[view_path]
  end
end

Learn more about nested views.

Second arg in field blocks

If you’re using the second argument in your field/association blocks, it’s no longer the render options. It’s now a Blueprinter::V2::Context::Field object, which contains the render options along with a lot more.

You can update your block in a single line:

field :description do |object, ctx|
  options = ctx.options
  # ...
end

Including a view

If you’re including a view in another view, replace include_view with use.

view :my_view do
  use :other_view
  # ...
end

This change may look superfluous, but it’s the result of a cool new feature: partials.

Transformers

Transforming a Blueprint’s output can be done using the around_blueprint extension hook. (See Blueprinter::Extension for full Extension API docs).

However, the LegacyTransformer extension offers compatibility with legacy/V1 transformer classes:

add Blueprinter::Extensions::LegacyTransformer.new(MyTransformer)

identifier

You can easily replicate legacy/V1’s identifier field and view in your base Blueprint:

class ApplicationBlueprint < Blueprinter::Extension
  # The id field will be added to all Blueprints and views
  field :id

  # All Blueprints will get an identifier view, and it will only ever contain id
  view :identifier do
    exclude fields: true
    field :id
  end
end