Install graphql gem & run install generator

Author: pgaspar

Gemfile

@@ -33,6 +33,8 @@ gem 'jbuilder', '~> 2.5'
 # Use Capistrano for deployment
 # gem 'capistrano-rails', group: :development
 
+gem 'graphql'
+
 group :development, :test do
   # Call 'byebug' anywhere in the code to stop execution and get a debugger console
   gem 'byebug', platforms: [:mri, :mingw, :x64_mingw]
@@ -52,3 +54,5 @@ end
 
 # Windows does not include zoneinfo files, so bundle the tzinfo-data gem
 gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]
+
+gem 'graphiql-rails', group: :development

Gemfile.lock

@@ -66,6 +66,9 @@ GEM
     ffi (1.9.18)
     globalid (0.4.0)
       activesupport (>= 4.2.0)
+    graphiql-rails (1.4.2)
+      rails
+    graphql (1.6.6)
     i18n (0.8.6)
     jbuilder (2.7.0)
       activesupport (>= 4.2.0)
@@ -177,6 +180,8 @@ DEPENDENCIES
   byebug
   capybara (~> 2.13)
   coffee-rails (~> 4.2)
+  graphiql-rails
+  graphql
   jbuilder (~> 2.5)
   listen (>= 3.0.5, < 3.2)
   puma (~> 3.7)

app/controllers/graphql_controller.rb

@@ -0,0 +1,33 @@
+class GraphqlController < ApplicationController
+  def execute
+    variables = ensure_hash(params[:variables])
+    query = params[:query]
+    operation_name = params[:operationName]
+    context = {
+      # Query context goes here, for example:
+      # current_user: current_user,
+    }
+    result = GraphqlTutorialSchema.execute(query, variables: variables, context: context, operation_name: operation_name)
+    render json: result
+  end
+
+  private
+
+  # Handle form data, JSON body, or a blank value
+  def ensure_hash(ambiguous_param)
+    case ambiguous_param
+    when String
+      if ambiguous_param.present?
+        ensure_hash(JSON.parse(ambiguous_param))
+      else
+        {}
+      end
+    when Hash, ActionController::Parameters
+      ambiguous_param
+    when nil
+      {}
+    else
+      raise ArgumentError, "Unexpected parameter: #{ambiguous_param}"
+    end
+  end
+end

app/graphql/graphql_tutorial_schema.rb

@@ -0,0 +1,4 @@
+GraphqlTutorialSchema = GraphQL::Schema.define do
+  mutation(Types::MutationType)
+  query(Types::QueryType)
+end

app/graphql/mutations/.keep

@@ -0,0 +1,5 @@
+Types::MutationType = GraphQL::ObjectType.define do
+  name "Mutation"
+
+  # TODO: Add Mutations as fields
+end

app/graphql/types/.keep

@@ -0,0 +1,13 @@
+Types::QueryType = GraphQL::ObjectType.define do
+  name "Query"
+  # Add root-level fields here.
+  # They will be entry points for queries on your schema.
+
+  # TODO: remove me
+  field :testField, types.String do
+    description "An example field added by the generator"
+    resolve ->(obj, args, ctx) {
+      "Hello World!"
+    }
+  end
+end

app/graphql/types/mutation_type.rb

@@ -1,3 +1,8 @@
 Rails.application.routes.draw do
+  if Rails.env.development?
+    mount GraphiQL::Rails::Engine, at: "/graphiql", graphql_path: "/graphql"
+  end
+
+  post "/graphql", to: "graphql#execute"
   # For details on the DSL available within this file, see http://guides.rubyonrails.org/routing.html
 end