Resources DSL

Defining a Resource

Generate a resource for an existing model:

rails generate quail:resource Article

Or write one by hand in app/graphql/resources/:

class ArticleResource
  include Quail::Resource

  attributes :id, :title, :body, :published_at

  has_many :comments
  belongs_to :author

  writable_attributes :title, :body
end

That single file gives you:

• A ArticleType GraphQL type with all declared fields and associations
• article(id: ID!) and articles queries (with Relay connection pagination)
• articleCreate, articleUpdate, articleDelete mutations
• Writable attributes scoped to only what you allow

Resource Generator Options

rails generate quail:resource Article \
  --attributes=id title body \
  --skip-mutations=delete \
  --subscribe-on=create update

Associations

class ArticleResource
  include Quail::Resource

  attributes :id, :title

  has_many :comments
  has_one :featured_image
  belongs_to :author, resource: AuthorResource
end

Associations resolve through the Quail resource registry. If a resource exists for the associated model, the type is wired up automatically.

Polymorphic Associations

Rails polymorphic belongs_to associations are supported. Since GraphQL requires a concrete type, you declare the possible resource types explicitly and Quail generates a union type:

class CommentResource
  include Quail::Resource

  attributes :id, :body

  belongs_to :commentable, polymorphic: { types: [PostResource, ImageResource] }
end

This generates a CommentableUnion GraphQL union type that resolves to PostType or ImageType at runtime based on the record’s commentable_type column. You can customize the union name:

belongs_to :commentable, polymorphic: {
  types: [PostResource, ImageResource],
  union_name: "CommentableTarget"
}

Delegated types work without any special configuration since each delegate maps to a concrete ActiveRecord class.

Computed Attributes

class ArticleResource
  include Quail::Resource

  attributes :id, :title

  attribute :excerpt, type: GraphQL::Types::String, null: true do |article|
    article.body&.truncate(200)
  end
end