Using GraphQL in Foxx

const createGraphQLRouter = require('@arangodb/foxx/graphql');

Foxx bundles the graphql-sync module, which is a synchronous wrapper for the official JavaScript GraphQL reference implementation, to allow writing GraphQL schemas directly inside Foxx.

Additionally the @arangodb/foxx/graphql lets you create routers for serving GraphQL requests, which closely mimicks the behaviour of the express-graphql module.

For more information on graphql-sync see the graphql-js API reference (note that graphql-sync always uses raw values instead of wrapping them in promises).

For an example of a GraphQL schema in Foxx that resolves fields using the database see the GraphQL example service (also available from the Foxx store).

Examples

const graphql = require('graphql-sync');
const graphqlSchema = new graphql.GraphQLSchema({
  // ...
});

// Mounting a graphql endpoint directly in a service:
module.context.use('/graphql', createGraphQLRouter({
  schema: graphqlSchema,
  graphiql: true
}));

// Or at the service's root URL:
module.context.use(createGraphQLRouter({
  schema: graphqlSchema,
  graphiql: true
}));

// Or inside an existing router:
router.get('/hello', function (req, res) {
  res.write('Hello world!');
});
router.use('/graphql', createGraphQLRouter({
  schema: graphqlSchema,
  graphiql: true
}));

Note: ArangoDB aims for stability which means bundled dependencies will generally not be updated as quickly as their maintainers make updates available on GitHub or NPM. Starting with ArangoDB 3.2, if you want to use a newer release of graphql-sync than the one bundled with your target version of ArangoDB, you can provide your own version of the library by passing it via the graphql option:

const graphql = require('graphql-sync');
const graphqlSchema = new graphql.Schema({
  //...
});
module.context.use(createGraphQLRouter({
  schema: graphqlSchema,
  graphiql: true,
  graphql: graphql
}))

This makes sure Foxx uses the graphql-sync module bundled in your service's node_modules folder (if available) instead of the built-in version. If you find graphql-sync itself lagging behind the official graphql module, consider opening an issue on its GitHub repository.

Creating a router

createGraphQLRouter(options): Router

This returns a new router object with POST and GET routes for serving GraphQL requests.

Arguments

• options: object

  An object with any of the following properties:

  • schema: GraphQLSchema

    A GraphQL Schema object from graphql-sync.

  • context: any (optional)

    The GraphQL context that will be passed to the graphql() function from graphql-sync to handle GraphQL queries.

  • rootValue: object (optional)

    The GraphQL root value that will be passed to the graphql() function from graphql-sync to handle GraphQL queries.

  • pretty: boolean (Default: false)

    If true, JSON responses will be pretty-printed.

  • formatError: Function (optional)

    A function that will be used to format errors produced by graphql-sync. If omitted, the formatError function from graphql-sync will be used instead.

  • validationRules: Array<any> (optional)

    Additional validation rules queries must satisfy in addition to those defined in the GraphQL spec.

  • graphiql: boolean (Default: false)

    If true, the GraphiQL explorer will be served when loaded directly from a browser.

  • graphql: object (optional)

    If you need to use your own copy of the graphql-sync module instead of the one bundled with ArangoDB, here you can pass it in directly.

If a GraphQL Schema object is passed instead of an options object it will be interpreted as the schema option.

Generated routes

The router handles GET and POST requests to its root path and accepts the following parameters, which can be provided either as query parameters or as the POST request body:

• query: string

  A GraphQL query that will be executed.

• variables: object | string (optional)

  An object or a string containing a JSON object with runtime values to use for any GraphQL query variables.

• operationName: string (optional)

  If the provided query contains multiple named operations, this specifies which operation should be executed.

• raw: boolean (Default: false)

  Forces a JSON response even if graphiql is enabled and the request was made using a browser.

The POST request body can be provided as JSON or as query string using application/x-www-form-urlencoded. A request body passed as application/graphql will be interpreted as the query parameter.