Basic graphql ruby implementation, using Query, Input, Resolvers, Types and Mutations

app-graphql-ruby.rb

require 'graphql'
require 'awesome_print'

#########
# TYPES #
#########

module Types
  class BaseObject < GraphQL::Schema::Object
  end
end

module Types
  class Item < Types::BaseObject
    description 'Resembles a Item Object Type'
    field :id, ID, null: false
    field :title, String, null: false
  end
end

##########
# INPUTS #
##########

module Inputs
  class ItemAttributes < GraphQL::Schema::InputObject
    description "Attributes for creating or updating a blog post"
    argument :title, String, required: true
  end
end

#############
# RESOLVERS #
#############

module Resolvers
  # resolvers base
  class Base < GraphQL::Schema::Resolver
    # argument_class Arguments::Base
  end
end

module Resolvers
  # item resolver
  class Item < GraphQL::Schema::Resolver
    type Types::Item, null: false

    argument :id, ID, required: true

    def resolve(id:)
      { title: id }
    end
  end
end

module Resolvers
  # item resolver
  class Items < GraphQL::Schema::Resolver
    type [Types::Item], null: false

    argument :page, Int, required: false

    def resolve(page: nil)
      [
        { title: page },
        { title: page }
      ]
    end
  end
end

#############
# MUTATIONS #
#############

module Mutations
  class BaseMutation < GraphQL::Schema::Mutation
  end
end

module Mutations
  class CreateItem < Mutations::BaseMutation
    description 'Creates an item'

    argument :item_attributes, ::Inputs::ItemAttributes, required: true

    field :item, ::Types::Item, null: false
    field :errors, [String], null: false

    def resolve(item_attributes:)
      {
        item: { title: item_attributes.dig(:title) },
        errors: [ 'a', 'b' ]
      }
    end
  end
end

########
# BASE #
########

class MutationType < GraphQL::Schema::Object
  description "The mutation root of this schema"

  field :createItem, mutation: Mutations::CreateItem
end

class QueryType < GraphQL::Schema::Object
  description "The query root of this schema"

  field :item, resolver: ::Resolvers::Item, description: 'ok item'
  field :items, resolver: ::Resolvers::Items, description: 'ok items'

  def speakers
    []
  end
end

##############
# ENTRYPOINT #
##############

class AppSchema < GraphQL::Schema
  query QueryType
  mutation MutationType
end


############
# EXECUTER #
############

def execute(query, variables)
  AppSchema.execute(
    query,
    variables: variables,
    context: { current_user: nil },
  )
end

#################
# TEST MUTATION #
#################

mutation_query = "
  mutation CreateItem($attributes: ItemAttributes!) {
    createItem(itemAttributes: $attributes) {
      item {
        title
      }
    }
  }
"
mutation_variables = { attributes: { title: 'cool' } }
ap execute(mutation_query, mutation_variables).to_h


#######################
# TEST RESOLVE (ITEM) #
#######################

item_query = "
  query ($id: ID!) {
    item(id: $id) {
      title
    }
  }
"
item_variables = { id: 'xyz' }
ap execute(item_query, item_variables).to_h


########################
# TEST RESOLVE (ITEMS) #
########################

items_query = "
  query ($page: Int) {
    items(page: $page) {
      title
    }
  }
"
items_variables = { page: 2 }
ap execute(items_query, items_variables).to_h

run.sh

#!/bin/sh

FILE="./Gemfile"
/bin/cat <<EOM >$FILE
# frozen_string_literal: true
source 'https://rubygems.org'
git_source(:github) { |repo| "https://github.com/#{repo}.git" }
ruby '2.5.1'
gem 'graphql'
gem 'awesome_print'
EOM

bundle install && ruby app.rb