Apollo RESTDataSource 调用其他 RESTDataSource？

Question

假设我有 2 个扩展 RESTDataSource 的 API 类：

class MoviesAPI extends RESTDataSource {

async getMovies() {}

}

class SongsAPI extends RESTDataSource {

async getSongs() {}

}

如何getSongs从getMovies现有的 Apollo 服务器上下文中调用？

Answer 1

this.context您可以通过在数据源类中获取 apollo 服务器上下文并dataSources通过this.context.dataSources.例如server.ts:import { ApolloServer, gql } from 'apollo-server';import { MoviesAPI } from './MoviesAPI';import { SongsAPI } from './SongsAPI';const typeDefs = gql`  type Query {    movies: String  }`;const resolvers = {  Query: {    movies: (_, __, { dataSources }) => {      return dataSources.moviesAPI.getMovies();    },  },};const server = new ApolloServer({  typeDefs,  resolvers,  dataSources: () => {    return {      moviesAPI: new MoviesAPI(),      songsAPI: new SongsAPI(),    };  },});server.listen().then(({ url }) => {  console.log(`Apollo server is listening on ${url}`);});MoviesAPI.ts:import { RESTDataSource } from 'apollo-datasource-rest';export class MoviesAPI extends RESTDataSource {  async getMovies() {    const songs = await this.context.dataSources.songsAPI.getSongs();    const movies = ['a', 'b'];    return JSON.stringify({ movies, songs });  }}SongsAPI.ts:import { RESTDataSource } from 'apollo-datasource-rest';export class SongsAPI extends RESTDataSource {  async getSongs() {    return ['x', 'y'];  }}从客户端发送 GraphQL 查询：query{  movies}响应负载：{  "data": {    "movies": "{\"movies\":[\"a\",\"b\"],\"songs\":[\"x\",\"y\"]}"  }}包版本："apollo-datasource-rest": "^0.8.1","apollo-server": "^2.12.0"源代码：https ://github.com/mrdulin/apollo-graphql-tutorial/tree/master/src/stackoverflow/61425326