graphql-yoga

Fully-featured GraphQL Server with focus on easy setup, performance & great developer experience

Overview

Easiest way to run a GraphQL server: Sensible defaults & includes everything you need with minimal setup.
Includes Subscriptions: Built-in support for GraphQL subscriptions using WebSockets.
Compatible: Works with all GraphQL clients (Apollo, Relay...) and fits seamless in your GraphQL workflow.

graphql-yoga is based on the following libraries & tools:

express/apollo-server: Performant, extensible web server framework
graphql-subscriptions/subscriptions-transport-ws: GraphQL subscriptions server
graphql.js/graphql-tools: GraphQL engine & schema helpers
graphql-playground: Interactive GraphQL IDE

Features

GraphQL spec-compliant
File upload
GraphQL Subscriptions
TypeScript typings
GraphQL Playground
Extensible via Express middlewares
Schema directives
Apollo Tracing
Accepts both application/json and application/graphql content-types
Runs everywhere: Can be deployed via now, up, AWS Lambda, Heroku etc.
Supports middleware out of the box.

Install

yarn add graphql-yoga

Usage

Quickstart (Hosted demo)

import { GraphQLServer } from 'graphql-yoga'
// ... or using `require()`
// const { GraphQLServer } = require('graphql-yoga')

const typeDefs = `
  type Query {
    hello(name: String): String!
  }
`

const resolvers = {
  Query: {
    hello: (_, { name }) => `Hello ${name || 'World'}`,
  },
}

const server = new GraphQLServer({ typeDefs, resolvers })
server.start(() => console.log('Server is running on localhost:4000'))

To get started with graphql-yoga, follow the instructions in the READMEs of the examples.

API

`GraphQLServer`

`constructor(props: Props): GraphQLServer`

The props argument accepts the following fields:

Key	Type	Default	Note
`typeDefs`	`String` or `Function` or `DocumentNode` or `array` of previous	`null`	Contains GraphQL type definitions in SDL or file path to type definitions (required if `schema` is not provided *)
`resolvers`	Object	`null`	Contains resolvers for the fields specified in `typeDefs` (required if `schema` is not provided *)
`resolverValidationOptions`	Object	`null`	Object which controls the resolver validation behaviour (see "Generating a schema") for more information
`schema`	Object	`null`	An instance of `GraphQLSchema` (required if `typeDefs` and `resolvers` are not provided *)
`mocks`	Object or Boolean	`null`	Applies mocks to schema. Setting this to true will apply a default mock, however you can pass an object to customize the mocks similar to the resolvers map.
`context`	Object or Function	`{}`	Contains custom data being passed through your resolver chain. This can be passed in as an object, or as a Function with the signature `(req: ContextParameters) => any` **
`schemaDirectives`	Object	`null`	`Apollo Server schema directives` that allow for transforming schema types, fields, and arguments
`middlewares`	`array` of Middleware	`[]`	A list of `GraphQLMiddleware` middleware.

(*) There are two major ways of providing the schema information to the constructor:

Provide typeDefs and resolvers and omit the schema, in this case graphql-yoga will construct the GraphQLSchema instance using makeExecutableSchema from graphql-tools.

Provide the schema directly and omit typeDefs and resolvers.

(**) Notice that the req argument is an object of the shape { request, response, connection } which either carries a request: Request property (when it's a Query/Mutation resolver), response: Response property (when it's a Query/Mutation resolver), or a connection: SubscriptionOptions property (when it's a Subscription resolver). Request is imported from Express.js. Response is imported from Express.js aswell. SubscriptionOptions is from the graphql-subscriptions package. SubscriptionOptions are getting the connectionParams automatically injected under SubscriptionOptions.context.[CONNECTION_PARAMETER_NAME]

Here is example of creating a new server:

const typeDefs = `
  type Query {
    hello(name: String): String!
  }
`

const resolvers = {
  Query: {
    hello: (_, { name }) => `Hello ${name || 'World'}`,
  },
}

const server = new GraphQLServer({ typeDefs, resolvers })

`start(options: Options, callback: ((options: Options) => void) = (() => null)): Promise<void>`

Once your GraphQLServer is instantiated, you can call the start method on it. It takes two arguments: options, the options object defined above, and callback, a function that's invoked right before the server is started. As an example, the callback can be used to print information that the server has started.

The options object has the following fields:

Key	Type	Default	Note
`cors`	Object	`null`	Contains configuration options for cors
`tracing`	Boolean or TracingOptions	`'http-header'`	Indicates whether Apollo Tracing should be enabled or disabled for your server (if a string is provided, accepted values are: `'enabled'`, `'disabled'`, `'http-header'`)
`port`	Number or String	`4000`	Determines the port your server will be listening on (note that you can also specify the port by setting the `PORT` environment variable)
`endpoint`	String	`'/'`	Defines the HTTP endpoint of your server
`subscriptions`	Object or String or `false`	`'/'`	Defines the subscriptions (websocket) endpoint for your server; accepts an object with subscription server options `path`, `keepAlive`, `onConnect` and `onDisconnect`; setting to `false` disables subscriptions completely
`playground`	String or `false`	`'/'`	Defines the endpoint where you can invoke the Playground; setting to `false` disables the playground endpoint
`uploads`	UploadOptions or `false` or `undefined`	`null`	Provides information about upload limits; the object can have any combination of the following three keys: `maxFieldSize`, `maxFileSize`, `maxFiles`; each of these have values of type Number; setting to `false` disables file uploading
`https`	HttpsOptions or `undefined`	`undefined`	Enables HTTPS support with a key/cert
`getEndpoint`	String or Boolean	`false`	Adds a graphql HTTP GET endpoint to your server (defaults to `endpoint` if `true`). Used for leveraging CDN level caching.
`deduplicator`	Boolean	`true`	Enables graphql-deduplicator. Once enabled sending the header `X-GraphQL-Deduplicate` will deduplicate the data.
`bodyParserOptions`	BodyParserJSONOptions	BodyParserJSONOptions Defaults	Allows pass through of body-parser options

Additionally, the options object exposes these apollo-server options:

Key	Type	Note
`cacheControl`	Boolean	Enable extension that returns Cache Control data in the response
`formatError`	Number	A function to apply to every error before sending the response to clients. Defaults to defaultErrorFormatter. Please beware, that if you override this, `requestId` and `code` on errors won't automatically be propagated to your yoga server
`logFunction`	LogFunction	A function called for logging events such as execution times
`rootValue`	any	RootValue passed to GraphQL execution
`validationRules`	Array of functions	Additional GraphQL validation rules to be applied to client-specified queries
`fieldResolver`	GraphQLFieldResolver	Specify a custom default field resolver function
`formatParams`	Function	A function applied to each query in a batch to format parameters before execution
`formatResponse`	Function	A function applied to each response after execution
`debug`	boolean	Print additional debug logging if execution errors occur

const options = {
  port: 8000,
  endpoint: '/graphql',
  subscriptions: '/subscriptions',
  playground: '/playground',
}

server.start(options, ({ port }) =>
  console.log(
    `Server started, listening on port ${port} for incoming requests.`,
  ),
)

`PubSub`

See the original documentation in graphql-subscriptions.

`mocking`

Mocking the schema is straight forward, along wit

import { GraphqlServer, MockList } from 'graphql-yoga';

const typeDefs = `
  type Query {
    hello(name: String): String!
    listOfStrings: [String]
  }
`

const mocks = {
  Query: () => ({
    hello: () => 'Hello World',
    listOfStrings: () => new MockList([2,6]),
  }),

}

const server = new GraphQLServer({ typeDefs, mocks })

Endpoints

Examples

There are three examples demonstrating how to quickly get started with graphql-yoga:

hello-world: Basic setup for building a schema and allowing for a hello query.
subscriptions: Basic setup for using subscriptions with a counter that increments every 2 seconds and triggers a subscription.
fullstack: Fullstack example based on create-react-app demonstrating how to query data from graphql-yoga with Apollo Client 2.0.

Workflow

Once your graphql-yoga server is running, you can use GraphQL Playground out of the box – typically running on localhost:4000. (Read here for more information.)

Deployment

`now`

To deploy your graphql-yoga server with now, follow these instructions:

Download Now Desktop
Navigate to the root directory of your graphql-yoga server
Run now in your terminal

Heroku

To deploy your graphql-yoga server with Heroku, follow these instructions:

Download and install the Heroku Command Line Interface (previously Heroku Toolbelt)
Log in to the Heroku CLI with heroku login
Navigate to the root directory of your graphql-yoga server
Create the Heroku instance by executing heroku create
Deploy your GraphQL server by executing git push heroku master

`up` (Coming soon 🔜 )

AWS Lambda (Coming soon 🔜 )

FAQ

How does `graphql-yoga` compare to `apollo-server` and other tools?

As mentioned above, graphql-yoga is built on top of a variety of other packages, such as graphql.js, express and apollo-server. Each of these provides a certain piece of functionality required for building a GraphQL server.

Using these packages individually incurs overhead in the setup process and requires you to write a lot of boilerplate. graphql-yoga abstracts away the initial complexity and required boilerplate and lets you get started quickly with a set of sensible defaults for your server configuration.

graphql-yoga is like create-react-app for building GraphQL servers.

Can't I just setup my own GraphQL server using `express` and `graphql.js`?

graphql-yoga is all about convenience and a great "Getting Started" experience by abstracting away the complexity that comes when you're building your own GraphQL server from scratch. It's a pragmatic approach to bootstrap a GraphQL server, much like how create-react-app removes friction when first starting out with React.

Whenever the defaults of graphql-yoga are too tight a corset for you, you can simply eject from it and use the tooling it's built upon - there's no lock-in or any other kind of magic going on preventing you from doing this.

How to eject from the standard `express` setup?

The core value of graphql-yoga is that you don't have to write the boilerplate required to configure your express.js application. However, once you need to add more customized behaviour to your server, the default configuration provided by graphql-yoga might not suit your use case any more. For example, it might be the case that you want to add more custom middleware to your server, like for logging or error reporting.

For these cases, GraphQLServer exposes the express.Application directly via its express property:

server.express.use(myMiddleware())

Middlewares can also be added specifically to the GraphQL endpoint route, by using:

server.express.post(server.options.endpoint, myMiddleware())

Any middlewares you add to that route, will be added right before the apollo-server-express middleware.

Help & Community

Join our Slack community if you run into issues or have questions. We love talking to you!

ChrBach/graphql-yoga