Apollo Server 作为 Nuxt 服务器中间件

Question

我已经设法在 Nuxtjs 中拥有一个 express + Apollo 后端作为 serverMiddleware。 一切正常（身份验证、缓存、数据源、查询、突变），但现在我正试图让订阅（websockets）运行，这让我很难过。

我试过这个例子https://www.apollographql.com/docs/apollo-server/data/subscriptions/#subscriptions-with-additional-middleware，但即使让httpServer监听也没有用。

这是我通过 nuxt.config.js 使用 '~/api/index' 需要的 API 文件：

module.exports = async () => {
  const app = require('express')()
  const server = await require("./apollo")() // apollo-server-express w/ typeDefs and resolvers

  // apply Apollo to Express
  server.applyMiddleware({ app });
  console.log(`???? ApolloServer ready at ${server.graphqlPath}`);

  const httpServer = http.createServer(app);
  server.installSubscriptionHandlers(httpServer);
  console.log(`???? ApolloSubscriptions ready at ${server.subscriptionsPath}`);

  return {
    path: '/api',
    handler: httpServer
  }
}

现在我的游乐场给了我这个错误："Could not connect to websocket endpoint ws://192.168.150.98:3000/api/graphql. Please check if the endpoint url is correct."

类型定义：

type Subscription {
  postAdded: Post
}
type Post {
  author: String
  comment: String
}
type Query {
  posts: [Post]
}
type Mutation {
  addPost(author: String, comment: String): Post
}

解析器：

Query: {
  posts(root, args, context) {
    return Posts;
  }
}
Mutation: {
  addPost(root, args, context) {
    pubsub.publish(POST_ADDED, { postAdded: args });
    return Posts.add(args);
  }
},
Subscription: {
  postAdded: {
    // Additional event labels can be passed to asyncIterator creation
    subscribe: () => pubsub.asyncIterator([POST_ADDED]),
  },
}

这里的第一个问题，提前谢谢你！ :)

Answer 1

也可以轻松一点

1.

yarn add apollo-server-express

或

npm install apollo-server-express

1. 创建文件 ./server/index.js

import { ApolloServer, gql } from 'apollo-server-express'

    // Construct a schema, using GraphQL schema language
const typeDefs = gql`
  type Query {
    hello: String
  }
`

// Provide resolver functions for your schema fields
const resolvers = {
  Query: {
    hello: () => 'Hello world!',
  },
}

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

export default server

1. 添加您的 nuxt.config.js

import server from './server'

export default {
// ... your nuxt config stuff
// ...
  hooks: {
    render: {
      async before({
        nuxt: {
          server: { app },
        },
      }) {
        await server.applyMiddleware({ app, path: '/api' })
        console.log(`? ApolloServer ready at /api`)
      },
    },
  }
}

Answer 2

我找到了一个 hacky 方法来实现它，将代码导入为 nuxt 模块：

import http from 'http'

export default function () {
  this.nuxt.hook('render:before', async () => {
    const server = require("./apollo")()
    
    // apply Apollo to Express
    server.applyMiddleware({ app: this.nuxt.renderer.app });
    console.log(`? ApolloServer ready at ${server.graphqlPath}`);
    
    const httpServer = http.createServer(this.nuxt.renderer.app);
    
    // apply SubscriptionHandlers to httpServer
    server.installSubscriptionHandlers(httpServer);
    console.log(`? ApolloSubscriptions ready at ${server.subscriptionsPath}`);

    // overwrite nuxt.server.listen()
    this.nuxt.server.listen = (port, host) => new Promise(resolve => httpServer.listen(port || 3000, host || 'localhost', resolve))
    
    // close this httpServer on 'close' event
    this.nuxt.hook('close', () => new Promise(httpServer.close))
  })
}

尽管我现在使用一种可能更稳定的方式，using nuxt programmatically！ 使用 hapi 而不是 express，因为 express 给我编译和不显示加载屏幕（构建进度）带来了麻烦。 只需使用 npx create-nuxt-app 并创建一个带有 hapi 服务器后端的应用程序。

带有 hapi 的代码如下所示：

const consola = require('consola')
const Hapi = require('@hapi/hapi')
const HapiNuxt = require('@nuxtjs/hapi')

async function start () {
  const server = require('./apollo/index')()
  const app = new Hapi.Server({
    host: process.env.HOST || '127.0.0.1',
    port: process.env.PORT || 3000
  })

  await app.register({
    plugin: HapiNuxt
  })
  
  app.route(await require('./routes')())
  
  await server.applyMiddleware({
    app,
    path: '/graphql'
  });
  console.log(`? ApolloServer ready at ${server.graphqlPath}`);
  await server.installSubscriptionHandlers(app.listener)
  console.log(`? ApolloSubscriptions ready at ${server.subscriptionsPath}`);

  await app.start()

  consola.ready({
    message: `Server running at: ${app.info.uri}`,
    badge: true
  })
}
process.on('unhandledRejection', error => consola.error(error))
start().catch(error => console.log(error))

也许我可以帮助别人

Answer 3

更简单的方法是使用 Apollo Server Express 的getMiddleware() 方法：

在./api/index.js下创建一个文件：

const { ApolloServer, gql } = require('apollo-server-express')
const express = require('express')

const typeDefs = gql`
  type Query {
    hello: String
  }
`

const resolvers = {
  Query: {
    hello: () => 'Hello world!',
  },
}

const server = new ApolloServer({ typeDefs, resolvers })
const app = express()

app.use(express.json())
app.use(express.urlencoded({ extended: true }))
app.use(server.getMiddleware())

module.exports = app

然后在./nuxt.config.js注册：

{
  // other nuxt config ...
  serverMiddleware: [{ path: '/api', handler: '~/api/index.js' }],
}