graphql

• Introduction
• API Documentation

Installation

Install from RubyGems by adding it to your Gemfile, then bundling.

# Gemfile
gem 'graphql'

$ bundle install

Overview

Declare types & build a schema

# Declare a type...
PostType = GraphQL::ObjectType.define do
  name "Post"
  description "A blog post"

  field :id, !types.ID
  field :title, !types.String
  field :body, !types.String
  field :comments, types[!CommentType]
end

# ...and a query root
QueryType = GraphQL::ObjectType.define do
  name "Query"
  description "The query root of this schema"

  field :post do
    type PostType
    argument :id, !types.ID
    resolve -> (obj, args, ctx) { Post.find(args["id"]) }
  end
end

# Then create your schema
Schema = GraphQL::Schema.new(query: QueryType)

See also:

• the test schema
• graphql-ruby-demo for an example schema on Rails

Execute queries

Execute GraphQL queries on a given schema, from a query string.

query = GraphQL::Query.new(Schema, query_string)
result_hash = query.result
# {
#   "data" => {
#     "post" => {
#        "id" => 1,
#        "title" => "GraphQL is nice"
#     }
#   }
# }

See also:

• query_spec.rb for an example of query execution.
• queries_controller.rb for a Rails example
• Try it on heroku

Use with Relay

If you're building a backend for Relay, you'll need:

• A JSON dump of the schema, which you can get by sending GraphQL::Introspection::INTROSPECTION_QUERY
• Relay-specific helpers for GraphQL like Connections, node fields, and global ids. Here's one example of those: graphql-relay

To Do

• To match spec:
  • Directives:
    • @skip has precedence over @include
    • directives on fragments: http://facebook.github.io/graphql/#sec-Fragment-Directives
  • Union
    • only require one type https://github.com/facebook/graphql/commit/972fd5aae01195b018d305c82e43f714f9a41679
• Field merging
  • if you were to request a field, then request it in a fragment, it would get looked up twice
  • graphql/graphql-js#19 (comment)
• Code clean-up
  • Accept native Ruby types in definitions, then convert them to GraphQL types
  • Remove deprecated params: keyword
  • Raise if you try to configure an attribute which doesn't suit the type
• Cook up some path other than "n+1s everywhere"
  • See Sangria's project approach (in progress)
  • Try debounced approach?

Goals

• Implement the GraphQL spec & support a Relay front end
• Provide idiomatic, plain-Ruby API with similarities to reference implementation where possible
• Support graphql-rails

Getting Involved

• Say hi & ask questions in the #ruby channel on Slack or on Twitter!
• Report bugs by posting a description, full stack trace, and all relevant code in a GitHub issue.
• Features & patches are welcome! Consider discussing it in an issue or in the #ruby channel on Slack to make sure we're on the same page.
• Run the tests with rake test or start up guard with bundle exec guard.

Other Resources

• GraphQL Spec
• Other implementations: graphql-links
• graphql-ruby + Rails demo (src / heroku)
• GraphQL Slack
• Example Relay support in Ruby

P.S.

• Thanks to @sgwilym for the great logo!
• Definition API heavily inspired by @seanchas's implementation of GraphQL