[英]Error setting up simple server with middleware on node.js express
我对Node Express很陌生,并且正在尝试使用中间件设置一个简单的服务器来处理路由。 我得到的错误是TypeError: Router.use() requires a middleware function but got a Object
错误是由于app.get('/', require(routes));
线。 有人知道我需要把这里作为中间件功能吗?
//server.js
http = require('http');
let port = process.env.PORT || 3000;
let host = '127.0.0.1';
var express = require('express');
var app = express();
var routes = './api/routes/positions';
app.use('/', require(routes));
http.createServer(app).listen(port);
console.log('Listening at http://' + host + ':' + port);
//#########################
//positions.js
const express = require('express');
var router = express.Router();
router.get('/', (err, req, res, next) => {
res.status(200).json({
message: "hello from server"
});
});
module.exports.router;
#!/usr/bin/env node
/**
* Module dependencies.
*/
var app = require('../app');
var debug = require('debug')('ag:server');
var http = require('http');
/**
* Get port from environment and store in Express.
*/
var port = normalizePort(process.env.PORT || '3002');
app.set('port', port);
/**
* Create HTTP server.
*/
var server = http.createServer(app);
/**
* Listen on provided port, on all network interfaces.
*/
server.listen(port);
server.on('error', onError);
server.on('listening', onListening);
/**
* Normalize a port into a number, string, or false.
*/
function normalizePort(val) {
var port = parseInt(val, 10);
if (isNaN(port)) {
// named pipe
return val;
}
if (port >= 0) {
// port number
return port;
}
return false;
}
/**
* Event listener for HTTP server "error" event.
*/
function onError(error) {
if (error.syscall !== 'listen') {
throw error;
}
var bind = typeof port === 'string'
? 'Pipe ' + port
: 'Port ' + port;
// handle specific listen errors with friendly messages
switch (error.code) {
case 'EACCES':
console.error(bind + ' requires elevated privileges');
process.exit(1);
break;
case 'EADDRINUSE':
console.error(bind + ' is already in use');
process.exit(1);
break;
default:
throw error;
}
}
/**
* Event listener for HTTP server "listening" event.
*/
function onListening() {
var addr = server.address();
var bind = typeof addr === 'string'
? 'pipe ' + addr
: 'port ' + addr.port;
debug('Listening on ' + bind);
}
您正在从positions.js
文件中以错误的方式导出模块。
你需要写
module.exports = router
代替,
module.exports.router
您编写的内容会将一个新的密钥router
绑定到exports
对象,但尚未为其分配任何值,因此它将返回到默认的空对象{}
。
现在express期望功能,但是得到了对象,因此出现了错误。 您可以通过检查server.js
文件中的require(routes)
来验证它。
请研究此格式的代码。
const http = require('http');
const express = require('express');
const routes = require('./api/routes/positions');
const port = process.env.PORT || 3000;
const host = '127.0.0.1';
const app = express();
app.use('/', routes);
http.createServer(app).listen(port);
console.log('Listening at http://' + host + ':' + port);
如果您想阅读更多项目,可以阅读我写的这个样板 。 它有点旧,但可能会为您服务。
试试这个:
//server.js
let port = process.env.PORT || 3000;
let host = '127.0.0.1';
var express = require('express');
var app = express();
var routes = require('./api/routes/positions');
http.createServer(app).listen(port);
console.log('Listening at http://' + host + ':' + port);
//#########################
//positions.js
const express = require('express');
var router = express.Router();
router.use('/', routes);
app.use('/', routes);
router.get('/', (err, req, res, next) => {
res.status(200).json({
message: "hello from server"
});
});
module.exports = router;
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