GraphQL::Extras

A collection of utilities for building GraphQL APIs.

Table of Contents

• Installation
• Usage
  • GraphQL::Extras::Controller
  • GraphQL::Extras::Preload
  • GraphQL::Extras::PreloadSource
  • GraphQL::Extras::Types
    • Date
    • DateTime
    • Decimal
    • Upload
  • GraphQL::Extras::Test
• Development
• Contributing

Installation

Add this line to your application's Gemfile:

gem 'graphql-extras'

And then execute:

$ bundle

Usage

GraphQL::Extras::Controller

The graphql gem will generate a controller for you with a bunch of boilerplate. This module will encapsulate that boilerplate:

class GraphqlController < ApplicationController
  include GraphQL::Extras::Controller

  def execute
    graphql(schema: MySchema, context: { current_user: current_user })
  end
end

GraphQL::Extras::Preload

This allows you to preload associations before resolving fields.

class Schema < GraphQL::Schema
  use GraphQL::Dataloader
end

class BaseField < GraphQL::Schema::Field
  prepend GraphQL::Extras::Preload
end

class BaseObject < GraphQL::Schema::Object
  field_class BaseField
end

class PostType < BaseObject
  field :author, AuthorType, preload: :author, null: false
  field :author_posts, [PostType], preload: {author: :posts}, null: false
  field :depends_on_author, Integer, preload: :author, null: false

  def author_posts
    object.author.posts
  end
end

GraphQL::Extras::PreloadSource

This is a subclass of GraphQL::Dataloader::Source that performs eager loading of Active Record associations.

loader = dataloader.with(GraphQL::Extras::PreloadSource, :blog)
loader.load(Post.first)
loader.load_many(Post.all)

GraphQL::Extras::Types

In your base classes, you should include the GraphQL::Extras::Types.

class BaseObject < GraphQL::Schema::Object
  include GraphQL::Extras::Types
end

class BaseInputObject < GraphQL::Schema::InputObject
  include GraphQL::Extras::Types
end

Date

This scalar takes a Date and transmits it as a string, using ISO 8601 format.

field :birthday, Date, required: true

DateTime

This scalar takes a DateTime and transmits it as a string, using ISO 8601 format.

field :created_at, DateTime, required: true

Note: This is just an alias for the ISO8601DateTime type that is included in the graphql gem.

Decimal

This scalar takes a BigDecimal and transmits it as a string.

field :weight, BigDecimal, required: true

Upload

This scalar is used for accepting file uploads.

field :image, Upload, required: true

It achieves this by passing in all file upload parameters through context. This will work out of the box if you're using GraphQL::Extras::Controller.

Here's an example using CURL:

$ curl -X POST \
    -F query='mutation { uploadFile(image: "image") }' \
    -F image=@cats.png \
    localhost:3000/graphql

Take note of the correspondence between the value "image" and the additional HTTP parameter called -F image=@cats.png.

See apollo-link-upload for the client-side implementation.

GraphQL::Extras::Test

This module makes it really easy to test your schema.

First, create a test schema:

# spec/support/test_schema.rb
require "graphql/extras/test"

class TestSchema < GraphQL::Extras::Test::Schema
  configure schema: Schema, queries: "spec/**/*.graphql"
end

Now, you can run tests like so:

require "support/test_schema"

RSpec.describe "hello" do
  let(:context) { { name: "Ray" } }
  let(:schema)  { TestSchema.new(context) }

  it "allows easily executing queries" do
    query = schema.hello

    expect(query).to be_successful
    expect(query.data["hello"]).to eq("world")
  end

  it "parses errors" do
    query = schema.kaboom

    expect(query).not_to be_successful
    expect(query.errors[0].message).to eq("Invalid")
    expect(query.errors[0].code).to eq("VALIDATION_ERROR")
  end
end

Development

To install dependencies:

$ bundle install

To run the test suite:

$ bundle exec rspec

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/rzane/graphql-extras.

License

GraphQL::Extras is released under the MIT License.