apollo-datasource-http

Apollo HTTP Data Source

Optimized HTTP Data Source for Apollo Server

• JSON by default
• HTTP/1 Keep-alive agents for socket reuse
• HTTP/2 support (requires Node.js 15.10.0 or newer)
• Uses Got a modern HTTP Client shipped with:
  • Retry mechanism
  • Request cancellation
  • Timeout handling
  • RFC 7234 compliant HTTP caching
• Request Deduplication and a Resource Cache
• Support AbortController to manually cancel all running requests
• Support for Apollo Cache Storage backend

Documentation

View the Apollo Server documentation for data sources for more details.

Usage

To get started, install the apollo-datasource-http package:

npm install apollo-datasource-http

To define a data source, extend the HTTPDataSource class and implement the data fetching methods that your resolvers require. Data sources can then be provided via the dataSources property to the ApolloServer constructor, as demonstrated in the section below.

const server = new ApolloServer({
  typeDefs,
  resolvers,
  dataSources: () => {
    return {
      moviesAPI: new MoviesAPI(),
    }
  },
})

Your implementation of these methods can call on convenience methods built into the HTTPDataSource class to perform HTTP requests, while making it easy to pass different options and handle errors.

import { HTTPDataSource } from "apollo-datasource-http";

const datasource = new (class MoviesAPI extends HTTPDataSource {
  constructor() {
    // global client options
    super({
      requestOptions: {
        timeout: 2000,
        http2: true,
        headers: {
          "X-Client": "client",
        },
      },
    });
    this.baseURL = "https://movies-api.example.com";
  })

  onCacheKeyCalculation(requestOptions: RequestOptions): string {
    // return different key based on request options
  }
  onRequest(requestOptions: RequestOptions): void {
    // manipulate request
  }
  onResponse<TResult = unknown>(
    request: Request,
    response: Response<TResult>,
  ): void {
    // manipulate response or handle unsuccessful response in a different way
    return super.onResponse(request, response)
  }
  onError(
    error: RequestError
  ): void {
    // log errors
  }

  async getMovie(id) {
    return this.get(`/movies/${id}`, {
      headers: {
        "X-Foo": "bar",
      },
      timeout: 3000,
    });
  }
}

// cancel all running requests e.g when request is closed prematurely
datasource.abort()

Hooks

• onCacheKeyCalculation - Returns the cache key for request memoization.
• onRequest - Is executed before a request is made. This can be used to intercept requests (setting header, timeouts ...).
• onResponse - Is executed when a response has been received. This can be used to alter the response before it is passed to caller or to log errors.
• onError - Is executed for any error.

Error handling

The http client throws for unsuccessful responses (statusCode >= 400). In case of an request error onError is executed. By default the error is rethrown as an instance of ApolloError.