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node.js - 使用 AWS Lambda 的快速函数中的异步中间件 (TypeError)

问题描述

我想async在我的中间件中使用一个函数来提取我的 AWS Lambda 函数中的用户。

这是代码：

const bodyParser = require('body-parser');
const awsServerlessExpressMiddleware = require('aws-serverless-express/middleware');
const AWS = require('aws-sdk');

const asyncHandler = fn => (req, res, next) =>
  Promise.resolve(fn(req, res, next)).catch(next);

const pipe = (...fns) => x => fns.reduce((y, f) => f(y), x);
const tapRoute = f => route => {
  route.use(f);
  return route;
};

const configureCors = route => {
  route.use(function(req, res, next) {
    res.header('Access-Control-Allow-Origin', '*');
    res.header(
      'Access-Control-Allow-Headers',
      'Origin, X-Requested-With, Content-Type, Accept'
    );
    next();
  });
};
const injectUser = route => {
  route.use(async function(req, res, next) {
    try {
      const IDP_REGEX = /.*\/.*,(.*)\/(.*):CognitoSignIn:(.*)/;
      const authProvider =
        req.apiGateway.event.requestContext.identity
          .cognitoAuthenticationProvider;
      const [, , , userId] = authProvider.match(IDP_REGEX);
      console.log(userId);
      console.log('Got user id');

      const cognito = new AWS.CognitoIdentityServiceProvider();
      const listUsersResponse = await cognito
        .listUsers({
          UserPoolId: process.env.AUTH_LAMBDAUSERB2E6BC69_USERPOOLID,
          Filter: `sub = "${userId}"`,
          Limit: 1,
        })
        .promise();
      console.log('ListedUsers');
      const user = listUsersResponse.Users[0];
      req.user = user;
      next();
    } catch (error) {
      console.log(error);
      next(error);
    } finally {
      return route;
    }
  });
};

const applyMiddleware = (route, ...middleware) =>
  pipe(
    tapRoute(bodyParser.json()),
    tapRoute(awsServerlessExpressMiddleware.eventContext()),
    configureCors,
    injectUser,
    ...middleware
  )(route);

module.exports = {
  applyMiddleware,
};

代码在此行中引发错误：

route.use(async function(req, res, next) {

这是错误：

module initialization error: TypeError
at injectUser (/var/task/middleware.js:25:9)
at fns.reduce (/var/task/middleware.js:8:52)
at Array.reduce (<anonymous>)
at x (/var/task/middleware.js:8:35)
at applyMiddleware (/var/task/middleware.js:63:4)
at Object.<anonymous> (/var/task/app.js:13:1)
at Module._compile (module.js:652:30)
at Object.Module._extensions..js (module.js:663:10)
at Module.load (module.js:565:32)
at tryModuleLoad (module.js:505:12)

通常，我稍后会像这样使用这个中间件：

const express = require('express');
const applyMiddleware = require('./middleware').applyMiddleware;

const app = express();
applyMiddleware(app);

app.get( // ... rest of the code

但有时我也会在每条路由的基础上注入中间件。

到底是怎么回事？为什么会抛出这个 TypeError？有没有办法可以使用将用户注入管道的异步中间件，这样我就可以减少我的样板文件？如果我注释掉injectUser中间件的工作......

编辑：

使用app.use(async function // ...作品，但我想在我的pipeaka 中有异步功能。在applyMiddleware.

标签： node.jsexpressaws-lambdamiddlewareaws-serverless

解决方案

问题是你的configureCors功能。你不会在那里返回任何东西，所以链会被破坏并injectUser得到一个undefined route变量。它应该像下面这样更新

const configureCors = route => {
  route.use(function(req, res, next) {
    res.header('Access-Control-Allow-Origin', '*');
    res.header(
      'Access-Control-Allow-Headers',
      'Origin, X-Requested-With, Content-Type, Accept'
    );
    next();

  });
  return route;
};

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