Error: You must `await server.start()` before calling `server.applyMiddleware()`

Question

将 apollo-server 更新到版本 3 后，控制台中显示以下错误

C:\projects\my_project\node_modules\apollo-server-core\src\ApolloServer.ts:554
      throw new Error(
            ^
Error: You must `await server.start()` before calling `server.applyMiddleware()`
    at ApolloServer.assertStarted (C:\projects\my_project\node_modules\apollo-server-core\src\ApolloServer.ts:554:13)
    at ApolloServer.applyMiddleware (C:\projects\my_project\node_modules\apollo-server-express\src\ApolloServer.ts:60:10)
    at Object.<anonymous> (C:\projects\my_project\src\index.ts:17:14)
    at Module._compile (internal/modules/cjs/loader.js:1063:30)
    at Module.m._compile (C:\projects\my_project\node_modules\ts-node\src\index.ts:1225:23)
    at Module._extensions..js (internal/modules/cjs/loader.js:1092:10)
    at Object.require.extensions.<computed> [as .ts] (C:\projects\my_project\node_modules\ts-node\src\index.ts:1228:12)
    at Module.load (internal/modules/cjs/loader.js:928:32)
    at Function.Module._load (internal/modules/cjs/loader.js:769:14)
    at Function.executeUserEntryPoint [as runMain] (internal/modules/run_main.js:72:12)
[nodemon] app crashed - waiting for file changes before starting...

在 server.applyMiddleware() 之前添加 server.start() 并不能解决问题。有什么建议吗？

Answer 1

我按照文档中的 this guide 解决了这个问题。

此示例是从文档中复制粘贴的

import { ApolloServer } from 'apollo-server-express';
import express from 'express';

async function startApolloServer(typeDefs, resolvers) {
  // Same ApolloServer initialization as before
  const server = new ApolloServer({ typeDefs, resolvers });

  // Required logic for integrating with Express
  await server.start();

  const app = express();

  server.applyMiddleware({
     app,

     // By default, apollo-server hosts its GraphQL endpoint at the
     // server root. However, *other* Apollo Server packages host it at
     // /graphql. Optionally provide this to match apollo-server.
     path: '/'
  });

  // Modified server startup
  await new Promise(resolve => app.listen({ port: 4000 }, resolve));
  console.log(` Server ready at http://localhost:4000${server.graphqlPath}`);
}

Answer 2

在 apollo server 3 中，您只包含您需要的内容。要将所需的逻辑与 Express 集成，您需要在实例化服务器后调用 await server.start()。

示例：

...

const apolloServer = new ApolloServer({
  schema,
  ... // other config
});

// without this, apollo will throw an error.
await apolloServer.start();

const app = express();

apolloServer.applyMiddleware({
  app,
  ... // other config
});

...

检查新的 apollo 文档以了解更改 here

Answer 3

这对我有用，可以替代 await server.start()

server.start().then(res => {
  server.applyMiddleware({ app, path: '/' });
  app.listen({ port }, () => 
    console.log(`Gateway API running at port: ${port}`)
  );  
});

这个 post 让我找到了答案。