Apollo Server Express + 订阅错误

Question

我正在开发一个 Express 后端项目 (Apollo Server + Express + GraphQL)，它的前端部分是用 React 制作的。

我想根据数据库更改在前端进行一些更改。例如，当创建用户时。我正在阅读一些文件，直到到达Apollo documentation regarding React subscriptions。

然后我读了Apollo Boost migration to set up client manually，因为它不支持订阅。然后我继续前进到setting up Express to support subscriptions，但我的代码不起作用。

这是我在控制台中遇到的错误：

app.use(process.env.GRAPHQL_PATH, _bodyParser["default"].json(), (0, _apolloServerExpress.graphqlExpress)({

TypeError: (0 , _apolloServerExpress.graphqlExpress) 不是函数 在对象。 (C:\Web\backend\src/index.js:83:5)

这是第 83 行：graphqlExpress({ schema })，我在下面的右侧做了评论。

首先我的快递是这样的：

import cors from 'cors';
import express from 'express';
import jwt from 'jsonwebtoken';
import mongoose from 'mongoose';
import { ApolloServer, AuthenticationError } from 'apollo-server-express';
import errorMessages from './mensajes/errors.json';
require('dotenv').config();

import schemas from './schemas';
import resolvers from './resolvers';

import userModel from './models/usuario';

const app = express();

app.use(cors());

const getUser = async (req) => {
    const token = req.headers.token;

    if (token) {
        try {
            return await jwt.verify(token, process.env.JWT_SECRET);
        } catch (e) {
            throw new AuthenticationError(mensajesError.sesionExpirada);
        }
    }
};

const server = new ApolloServer({
    typeDefs: schemas,
    resolvers,
    context: async ({ req }) => {
        if (req) {
            const me = await getUser(req);

            return {
                me,
                models: {
                    userModel
                },
            };
        }
    }
});

server.applyMiddleware({ app, path: process.env.GRAPHQL_PATH });

const options = { 
    useNewUrlParser: true, 
    useUnifiedTopology: true, 
    useCreateIndex: true 
};

app.listen(process.env.PORT, () => {
    console.clear();
    mongoose.connect('mongodb://.../sandbox', options)
    .then(() => {
        console.log(`Database and server running on port ${process.env.PORT}`);
    })
    .catch(error => {
        console.error(`The server or the database cannot start:`);
        console.error(error);
    });
});

然后我根据之前的 Apollo 文档把我的代码改成了：

import { graphqlExpress } from 'apollo-server-express';
import { createServer } from 'http';
import { execute, subscribe } from 'graphql';
import { PubSub } from 'graphql-subscriptions';
import { SubscriptionServer } from 'subscriptions-transport-ws';
require('dotenv').config();

import schema from './schemas';
import resolvers from './resolvers';

import userModel from './models/usuario';

const app = express();

app.use(
    process.env.GRAPHQL_PATH,
    bodyParser.json(),
    graphqlExpress({ schema }) // <-- Line 83
);

const pubsub = new PubSub();
const server = createServer(app);

server.listen(process.env.PORT, () => {
    new SubscriptionServer({
        execute,
        subscribe,
        schema,
    }, {
        server,
        path: '/subscriptions'
    });
});

当然缺少很多信息，但我想我仍然必须了解这一点。你明白那个错误吗？任何 cmets 都表示赞赏。

Answer 1

我也尝试过使用subscriptions-transport-ws 但由于这个issue，它不起作用。

这是一个适合我的配置。

const http = require('http');
const { ApolloServer } = require('apollo-server-express');
const express = require('express');
const graphQlSchema = require("./graphql/schema");
const grapgQlResolvers = require("./graphql/resolvers");

const PORT = 3000;
const app = express();

const server = new ApolloServer({ 
  typeDefs: graphQlSchema, 
  resolvers: grapgQlResolvers,
});

server.applyMiddleware({ app, cors: true })

const httpServer = http.createServer(app);
server.installSubscriptionHandlers(httpServer);

httpServer.listen(PORT, () => {
    console.log(`? Server ready at http://localhost:${PORT}${server.graphqlPath}`)
    console.log(`? Subscriptions ready at ws://localhost:${PORT}${server.subscriptionsPath}`)
})