为什么Express / node.js中的路由器返回404

Question

I just generated Express app and added custom route (/configuration). But if I try to open http://localhost:3000/configuration , server returns 404 Not Found error. I checked the code and don't understand where is error.

app.js

var express = require('express');
var path = require('path');
var favicon = require('serve-favicon');
var logger = require('morgan');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');

var index = require('./routes/index');
var config_page = require('./routes/configuration');

var app = express();

// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'pug');

app.use(logger('dev'));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: false }));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));

app.use('/', index);
app.use('/configuration', config_page);

// catch 404 and forward to error handler
app.use(function(req, res, next) {
  var err = new Error('Not Found');
  err.status = 404;
  next(err);
});

// error handler
app.use(function(err, req, res, next) {
  // set locals, only providing error in development
  res.locals.message = err.message;
  res.locals.error = req.app.get('env') === 'development' ? err : {};

  // render the error page
  res.status(err.status || 500);
  res.render('error');
});

module.exports = app;

routes/configuration.js (routes/index.js is similar)

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

/* GET configuration page. */
router.get('/configuration', function(req, res, next) {
  res.render('configuration', { title: 'My App | Configuration' });
});

module.exports = router;

Answer 1

This code is the problem

// catch 404 and forward to error handler
app.use(function(req, res, next) {
  var err = new Error('Not Found');
  err.status = 404;
  next(err);
});

Also the current Url which is generated by your application is http://localhost:3000/configuration/configuration . If you make a query on this then it will work. Now if you wan to use it with http://localhost:3000/configuration . then you need to remove on path from anywhere. May be you can change in main file like this

app.use(logger('dev'));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: false }));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));

app.use('/', index);
app.use('/',config_page); //-----------> this is the line you need to change

How can it be used for error handling. Remove it and add this code to catch any error in application.

process.on('uncaughtException', function (err) {
  // This should not happen
  logger.error("Pheew ....! Something unexpected happened. This should be handled more gracefully. I am sorry. The culprit is: ", err);
});