如何在express.js中发送无效路径的自定义消息？

Question

The below method in express.js

var express = require('express'), app = express();
app.get('/users', function (req, res) {
    //Some logic
}

can be accessed using URL

http://<host-name>:<port>/users

If invalid path such as http://:/invalid-path, I get the following response

Cannot GET /invalid-path

Is there a way to send customized messages for invalid paths in express.js?

Answer 1

One way we can achieve this is with app.all eg

app.all('/*,function(req,res){
    var path = req.url;
    switch(path){
    case '/login':
      //logic
    default:
      res.send("Invalid");
    }
})

Answer 2

Yes, you are talking about a 404 not found page if I am not mistaking.

The way you do this with express, is actually very easy. Express matches routes in the order they are defined, which means, if you try to access a route that is not defined, it will try all the previous routes, until there are no more. So what you need is a route defined to catch any request not already matched.

How?

Easy, as the very last route defined(So no more routes are defined in the code after this route), you define the following route:

app.all(function(req, res, next) {
    // Your 404 logic here
}

Answer 3

You can create a middleare error, somelike this..

/middleware/error.js

exports.notFound = function(req, res, next) {
  res.status(404);
  res.render('not-found');
};

The not-found can be specific page with message of not found status.

Answer 4

After your routes you need to catch all the 404 (urls which are not served by any route) and then make some middlewares for error handling depending on the /path:

// 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 handlers
app.use('/api', function (err, req, res, next) {
    res.status(err.status || 500);
    res.json({
        message: err.message,
        error: err
    })
});

app.use(function (err, req, res, next) {
    res.status(err.status || 500);
    res.render('error', {
        message: err.message,
        error: err
    });
});

I made a custom error handler which shows a custom error page (you can modify the template in /views/error.jade), while for requests starting with /api (/api/something, etc..) I return a json error message.

This is /views/error.jade:

extends layout

block content
  h1= message
  h2= error.status
  pre #{error.stack}