Node Interface

Gemfile

@@ -12,7 +12,7 @@ gem 'sqlite3'
 # Use Puma as the app server
 gem 'puma', '~> 3.0'
 # Use GraphQL!
-gem 'graphql', '~> 1.4.2'
+gem 'graphql', '~> 1.4.3'
 # GraphiQL Interface
 gem 'graphiql-rails', '~> 1.4.1'
 

Gemfile.lock

@@ -49,7 +49,7 @@ GEM
       activesupport (>= 4.1.0)
     graphiql-rails (1.4.1)
       rails
-    graphql (1.4.2)
+    graphql (1.4.3)
     i18n (0.8.0)
     listen (3.0.8)
       rb-fsevent (~> 0.9, >= 0.9.4)
@@ -130,7 +130,7 @@ PLATFORMS
 DEPENDENCIES
   byebug
   graphiql-rails (~> 1.4.1)
-  graphql (~> 1.4.2)
+  graphql (~> 1.4.3)
   listen (~> 3.0.5)
   puma (~> 3.0)
   rails (~> 5.0.1)

app/models/graph/schema.rb

@@ -1,8 +1,23 @@
 module Graph
   Schema = GraphQL::Schema.define do
     query Graph::Types::Query
+
     resolve_type ->(obj, ctx) do
       Graph::Schema.types.values.find { |type| type.name == obj.class.name }
     end
+
+    id_from_object ->(object, type_definition, query_ctx) do
+      URI::GID.build(app: GlobalID.app, model_name: type_definition.name, model_id: object.id)
+    end
+
+    object_from_id ->(id, query_ctx) do
+      gid = GlobalID.parse(id)
+      possible_types = query_ctx.warden.possible_types(GraphQL::Relay::Node.interface)
+
+      return unless possible_types.map(&:name).include?(gid.model_name)
+      return unless gid.app == GlobalID.app
+
+      Object.const_get(gid.model_name).find(gid.model_id)
+    end
   end
 end

app/models/graph/types/film.rb

@@ -4,7 +4,9 @@ module Types
       name "Film"
       description "A single film."
 
-      field :id, types.ID, "The ID of the Film."
+      interfaces [GraphQL::Relay::Node.interface]
+
+      global_id_field :id
 
       field :title, types.String, "The title of this film"
       field :episodeID, types.Int, "The episode number of this film.", property: :episode_id

app/models/graph/types/person.rb

@@ -4,7 +4,9 @@ module Types
       name "Person"
       description "An individual person or character within the Star Wars universe."
 
-      field :id, types.ID, "The ID of the person."
+      interfaces [GraphQL::Relay::Node.interface]
+
+      global_id_field :id
 
       field :birthYear, types.String,
         "The birth year of the person, using the in-universe standard of BBY or ABY"\

app/models/graph/types/planet.rb

@@ -4,7 +4,9 @@ module Types
       name "Planet"
       description "A large mass, planet or planetoid in the Star Wars Universe, at the time of 0 ABY."
 
-      field :id, types.ID, "The ID of the person."
+      interfaces [GraphQL::Relay::Node.interface]
+
+      global_id_field :id
 
       field :name, types.String, "The name of this planet."
       field :diameter, types.Int, "The diameter of this planet in kilometers."

app/models/graph/types/query.rb

@@ -4,6 +4,10 @@ module Types
       name "Query"
       description "The query root of this schema"
 
+      # Relay
+      field :node, GraphQL::Relay::Node.field
+      field :nodes, GraphQL::Relay::Node.plural_field
+
       field :person, Graph::Types::Person do
         argument :id, types.ID
         resolve ->(_, args, _) { ::Person.find_by(id: args['id']) }

app/models/graph/types/species.rb

@@ -4,7 +4,9 @@ module Types
       name "Species"
       description "A type of person or character within the Star Wars Universe."
 
-      field :id, types.ID, "The ID of this species."
+      interfaces [GraphQL::Relay::Node.interface]
+
+      global_id_field :id
 
       field :name, types.String, "The name of this species."
       field :classification, types.String, "The classification of this species, such as \"mammal\" or \"reptile\"."

app/models/graph/types/starship.rb

@@ -4,9 +4,9 @@ module Types
       name "Starship"
       description "A single transport craft that has hyperdrive capability."
 
-      interfaces [Graph::Types::TransportInterface]
+      interfaces [GraphQL::Relay::Node.interface, Graph::Types::TransportInterface]
 
-      field :id, types.ID, "The ID of this starship."
+      global_id_field :id
 
       # Starship Specific Fields
 

app/models/graph/types/vehicle.rb

@@ -4,9 +4,9 @@ module Types
       name "Vehicle"
       description "A single transport craft that has hyperdrive capability."
 
-      interfaces [Graph::Types::TransportInterface]
+      interfaces [GraphQL::Relay::Node.interface, Graph::Types::TransportInterface]
 
-      field :id, types.ID, "The ID of this vehicle."
+      global_id_field :id
 
       # Vehicle Specific Fields
 

test/controllers/graphql_controller_test.rb

@@ -13,15 +13,15 @@ class GraphQLControllerTest < ActionDispatch::IntegrationTest
           "homeworld" => {
             "name" => "Tatooine"
           },
-          "id" => "242320449",
+          "id" => "gid://swapi/Person/242320449",
           "mass" => 77,
           "name" => "Luke Skywalker",
           "skinColor" => "fair",
         },
         "film" => {
           "director" => "George Lucas",
           "episodeID" => 4,
-          "id" => "846649883",
+          "id" => "gid://swapi/Film/846649883",
           "producers" => ["Gary Kurtz", "Rick McCallum"],
           "releaseDate" => "1977-05-25",
           "title" => "A New Hope"
@@ -30,7 +30,7 @@ class GraphQLControllerTest < ActionDispatch::IntegrationTest
           "climate" => "temperate",
           "diameter" => 12500,
           "gravity" => "1 standard",
-          "id" => "688730903",
+          "id" => "gid://swapi/Planet/688730903",
           "name" => "Alderaan",
           "orbitalPeriod" => 364,
           "population" => 2000.0,
@@ -46,13 +46,13 @@ class GraphQLControllerTest < ActionDispatch::IntegrationTest
           "eyeColors" => ["yellow", "red"],
           "hairColors" => ["n/a"],
           "homeworld" => { "name" => "Nal Hutta" },
-          "id" => "299344798",
+          "id" => "gid://swapi/Species/299344798",
           "language" => "Huttese",
           "name" => "Hutt",
           "skinColors" => ["green", "brown", "tan"],
         },
         "starship" => {
-          "id" => "113504200",
+          "id" => "gid://swapi/Starship/113504200",
           "name" => "Millennium Falcon",
           "model" => "YT-1300 light freighter",
           "MGLT" => 75,
@@ -79,7 +79,7 @@ class GraphQLControllerTest < ActionDispatch::IntegrationTest
           "starshipClass" => "Light freighter"
         },
         "vehicle" => {
-          "id" => "82948950",
+          "id" => "gid://swapi/Vehicle/82948950",
           "name" => "Snowspeeder",
           "model" => "t-47 airspeeder",
           "cargoCapacity" => 10.0,
@@ -105,6 +105,26 @@ class GraphQLControllerTest < ActionDispatch::IntegrationTest
     assert_equal expected, JSON.parse(response.body)
   end
 
+  test '#execute can execute node queries' do
+    starship = starships(:"millennium-falcon")
+
+    query = "
+      query {
+        node(id: \"#{starship.to_global_id.to_s}\") {
+           ... on Starship {
+             name
+           }
+        }
+      }
+    "
+
+    expected = { "data" => { "node" => { "name" => "Millennium Falcon" } } }
+
+    post graphql_url, params: { query: query }
+
+    assert_equal expected, JSON.parse(response.body)
+  end
+
   private
 
   def full_graphql_query