Add GraphiQL and GraphQL Controller

Gemfile

@@ -13,6 +13,8 @@ gem 'sqlite3'
 gem 'puma', '~> 3.0'
 # Use GraphQL!
 gem 'graphql', '~> 1.4.2'
+# GraphiQL Interface
+gem 'graphiql-rails', '~> 1.4.1'
 
 group :development, :test do
   # Call 'byebug' anywhere in the code to stop execution and get a debugger console

Gemfile.lock

@@ -47,6 +47,8 @@ GEM
     ffi (1.9.17)
     globalid (0.3.7)
       activesupport (>= 4.1.0)
+    graphiql-rails (1.4.1)
+      rails
     graphql (1.4.2)
     i18n (0.8.0)
     listen (3.0.8)
@@ -127,6 +129,7 @@ PLATFORMS
 
 DEPENDENCIES
   byebug
+  graphiql-rails (~> 1.4.1)
   graphql (~> 1.4.2)
   listen (~> 3.0.5)
   puma (~> 3.0)

app/controllers/graphql_controller.rb

@@ -0,0 +1,20 @@
+class GraphqlController < ApplicationController
+  def execute
+    query_string = params[:query].to_s
+    variables = ensure_hash(params[:variables])
+    result = ::Graph::Schema.execute(query_string, variables: variables)
+    render json: result
+  end
+
+  private
+
+  def ensure_hash(variables)
+    if variables.blank?
+      {}
+    elsif variables.is_a?(String)
+      JSON.parse(variables)
+    else
+      variables
+    end
+  end
+end

app/models/graph/query.rb

@@ -0,0 +1,9 @@
+module Graph
+  Query = GraphQL::ObjectType.define do
+    name "Query"
+    description "The query root of this schema"
+
+    # TODO(xuorig) Populate with real fields (GraphiQL crashes with no fields on root)
+    field :test, types.String, resolve: ->(_, _, _) { 'test' }
+  end
+end

config/application.rb

@@ -21,6 +21,5 @@ class Application < Rails::Application
     # Settings in config/environments/* take precedence over those specified here.
     # Application configuration should go into files in config/initializers
     # -- all .rb files in that directory are automatically loaded.
-    config.autoload_paths << Rails.root.join('app', 'graph')
   end
 end

config/routes.rb

@@ -1,3 +1,7 @@
 Rails.application.routes.draw do
-  # For details on the DSL available within this file, see http://guides.rubyonrails.org/routing.html
+  if Rails.env.development?
+    mount GraphiQL::Rails::Engine, at: "/graphiql", graphql_path: "/graphql"
+  end
+
+  post '/graphql', to: 'graphql#execute'
 end