为什么快递中间件不能在单独的文件中工作

Question

我想将我的路由器分解为单独的文件，而不是将所有 API 路由保存在一个文件中。因此，我尝试使用中间件识别用户 URL，并根据您在下面看到的 url 调用 api，但中间件功能不起作用。如何解决？

//这里是 INDEX.jS 文件代码

const express = require("express");
const dotenv = require("dotenv");

const app = express();

const PORT = process.env.PORT || 7000;
app.listen(PORT);

app.use("/users", require("./routes/users/users"));

//=============================================== ==============

//这里是 users.js 文件代码

const express = require("express");`enter code here`
const router = require("express").Router();


express().use(selectApi);

  function selectApi(req, res, next) {

console.log("this line also not executing") 


  switch(req.originalUrl){
      case '/':
          // calling api here from a nother separate file

      case '/user/:id'
         // calling api here from a nother separate file
  }
}



module.exports = router;

Answer 1

Express.js Routing Guide 中有一个示例。我已经稍微修改了它以适合您的示例。

users.js

var express = require('express')
var router = express.Router()

// middleware that is specific to this router
router.use(function timeLog (req, res, next) {
  console.log('Time: ', Date.now())
  next()
})
// define the home page route
router.get('/', function (req, res) {
  // calling api here from a nother separate file
})

router.get('/user/:id', function (req, res) {
  // calling api here from a nother separate file
})

module.exports = router

index.js

const express = require("express");
const dotenv = require("dotenv");

const app = express();

const PORT = process.env.PORT || 7000;
app.listen(PORT);

app.use("/users", require("./routes/users/users"));