graphql

A Ruby implementation of GraphQL.

• Guides

  • Introduction
  • Defining Your Schema
  • Executing Queries
  • Testing
  • Code Reuse
  • Security
  • Relay

• 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,
  max_depth: 8,
)

Execute queries

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

result_hash = Schema.execute(query_string)
# {
#   "data" => {
#     "post" => {
#        "id" => 1,
#        "title" => "GraphQL is nice"
#     }
#   }
# }

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, see GraphQL::Relay

Goals

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

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.

Related Projects

Code

• graphql-ruby + Rails demo (src / heroku)
• graphql-batch, a batched query execution strategy
• graphql-libgraphqlparser, bindings to libgraphqlparser, a C-level parser.

Blog Posts

• Building a blog in GraphQL and Relay on Rails Introduction, Part 1, Part 2
• https://medium.com/@khor/relay-facebook-on-rails-8b4af2057152
• https://blog.jacobwgillespie.com/from-rest-to-graphql-b4e95e94c26b#.4cjtklrwt
• http://mgiroux.me/2015/getting-started-with-rails-graphql-relay/
• http://mgiroux.me/2015/uploading-files-using-relay-with-rails/

To Do

• StaticValidation improvements
  • Use catch-all type/field/argument definitions instead of terminating traversal
  • Reduce ad-hoc traversals?
  • Validators are order-dependent, is this a smell?
  • Tests for interference between validators are poor
  • Maybe this is a candidate for a rewrite? Can it somehow work more closely with query analysis? Somehow support the Query#perform_validation refactor?
• Add Rails-y argument validations, eg less_than: 100, max_length: 255, one_of: [...]
  • Must be customizable
• Refactor Query#perform_validation, how can that be organized better?
• Relay:
  • GlobalNodeIdentification.to_global_id should receive the type name and object, not id. (Or, maintain the "type_name, id in, type_name, id out" pattern?)
  • Reduce duplication in ArrayConnection / RelationConnection
  • Improve API for creating edges (better RANGE_ADD support)
  • If the new edge isn't a member of the connection's objects, raise a nice error