suppose I have a simple express js application like the following:
var express = require('express');
var app = express();
app.get('/', function(req, res) {
return res.json({ hello: 'world' });
});
module.exports = app;
I want to be able to go to the command line, require the app, start the server and simulate a request. Something like this:
var app = require('./app');
app.listen(3000);
app.dispatch('/') // => {hello:"world"}
You can use run-middleware module exactly for that. This is working by creating new Request & Response objects, and call your app using those objects.
app.runMiddleware('/yourNewRoutePath',{query:{param1:'value'}},function(responseCode,body,headers){
// Your code here
})
More info:
Module page in Github & NPM;
Examples of use run-middleware module
Disclosure: I am the maintainer & first developer of this module.
These two options worked for me without any error:
option 1
app.post('/one/route', (req, res, next) => {
req.url = '/another/route'
req.method = 'GET'
next();
});
app.get('/another/route', (req, res) => {
console.log("Hi, I am another route");
});
option 2
app.post('/one/route', (req, res, next) => {
req.url = '/another/route'
req.method = 'GET'
app._router.handle(req, res, next);
});
app.get('/another/route', (req, res) => {
console.log("Hi, I am another route");
});
Express : 4.15.4
No extra library or npm module is required
this solution works perfectly by using express 4.16
(and optionally -express promise router , which is great wrapper for error handling)
its straightforward, without using router inside a router nor re-write the request, like in the other suggested answers
just change the URL in the request and return it to router handle function
const router = require('express-promise-router')();
router.post('/signin', function(req, res , next) {
if (req.body.Username === 'admin') {
req.url = '/admin/signin'
router.handle(req, res, next)
}
else { // default doctor
req.url = '/doctors/signin'
router.handle(req, res, next)
}
});
router.post('/doctors/signin',someCallback1)
router.post('/admin/signin',someCallback1)
As far as I am aware, there isn't a way to switch to a specific route internally, but there is a way to flag the request, then move on to the next route:
app.use((req, res, next) => {
if("nextRouteCondition"){
req.skip = true;
return next();
}
})
This may allow you to accomplish what you want to do.
Related
I am executing the following code in node.js. The code runs fine, but the tutorial tells us that :
Now go back and add the Content-Type header with a value of application/json and run the request again. You will get the “You sent
JSON” message back from the server.
1) I am not able to understand how can I set headers for this program!
2) Also If I am running the program without setting headers, then the message 'Server requires application/json' should be displayed. I am not seeing it being displayed anywhere. Where should it be displayed?
const express = require('express');
const app = express();
const requireJsonContent = () => {
return (req, res, next) => {
if (req.headers['content-type'] !== 'application/json') {
res.status(400).send('Server requires application/json')
} else {
next()
}
}
}
app.get('/', (req, res, next) => {
res.send('Welcome Home');
});
app.post('/', requireJsonContent(), (req, res, next) => {
res.send('You sent JSON');
})
app.listen(3000);
What I see In Your code is that, the function requireJsonContent that you defined Does not have parameters. So, you should add (req, res, next) as params to your function. Besides, inside it, you return a function without execution. However, I think You don't need that function, and your code should be like this:
app.post('/', (req, res) => {
if (req.headers['content-type'] !== 'application/json') {
res.status(400).send('Server requires application/json')
} else {
res.send('You sent JSON');
}
})
With express 4.x, you can either use res.set() or res.append(). Read differences between both methods here.
I am trying to learn Express for NodeJS but I came across this:
I am trying to add 2 middlewares depeding on url, so on the /user to do something and on root to do something different. However the root middleware is always called even if i dont use next() and if i access the "/" url, the root middleware is called twice.
const express = require('express');
const app = express();
app.use('/user', (req, res, next) => {
console.log('In user middleware ');
res.send('<h1>Hello from User page</h1>');
});
app.use('/', (req, res, next) => {
console.log('In slash middleware !');
res.send('<h1>Hello from Express !</h1>');
});
app.disable('etag');
app.listen(3000);
it should be get or post not use
-get or post are routes
-use is middleware function
check this
const express = require('express');
const app = express();
app.get('/user', (req, res, next) => {
console.log('In user middleware ');
res.send('<h1>Hello from User page</h1>');
});
app.get('/', (req, res, next) => {
console.log('In slash middleware !');
res.send('<h1>Hello from Express !</h1>');
});
app.disable('etag');
app.listen(3000);
From an issue at GitHub.com
https://github.com/expressjs/express/issues/3260
Hi #davidgatti my "root path middlware" I assume you are talking about
nr_one. If so, yes, of course it is executed on every request; app.use
is a prefix-match system. Every URL starts with /, so anything mounted
at / will of course get executed :)
Okay, I can't confirm this but I suspect from the tutorial you are following you might be missing a line.
As you said, app.use is a middleware which will be added to all the route
So when you load say some url where you expect the middleware then it won't know about the request type (post, put, delete or get request).
Any alternate for this could be to try something like this
app.use('/user', (req, res, next) => {
if (req.method === 'GET') {
console.log('In user middleware ');
res.send('<h1>Hello from User page</h1>');
}
});
Again, Just check and compare his code thoroughly
Adding this link from Justin's answer for reference
In order to avoid such a problem, you have to use the return keyword.
When you send a file to the server, use return.
Try the following code,
const express = require('express');
const app = express();
app.use('/user', (req, res, next) => {
console.log('In user middleware ');
return res.send('<h1>Hello from User page</h1>');
});
app.use('/', (req, res, next) => {
console.log('In slash middleware !');
return res.send('<h1>Hello from Express !</h1>');
});
app.disable('etag');
app.listen(3000);
At line 13 and 8, I used the return keyword.
So when you make http://localhost:3000/ request, you will receive
Hello from Express !
And whenever you make http://localhost:3000/user request, you will receive
Hello from User page
I am trying to define one global middleware which will work for all routes of my app. I tried some ways but still got some issues.
var _gMDLW = function (req, res, next) {
if(req.route) console.log('Called route ', req.route.path);
next();
}
// Working fine and result on _gMDLW is /route1
app.get('/route1', _gMDLW, function (req, res, next) { return res.sendStatus(200); })
var globalRouter = new express.Router()
// Working fine and result on _gMDLW is /view
globalRouter.route('/view')
.get(_gMDLW, function (req, res, next) { return res.sendStatus(200);})
app.use(globalRouter);
But problem is here
// Error in _gMDLW and getting /list instead of /items/list
var itemRouter = new express.Router()
itemRouter.route('/list')
.get(_gMDLW, function (req, res, next) { return res.sendStatus(200);})
app.use('/items', itemRouter)
Second Question is is there any way to define/add _gMDLW inside app instead of adding in each route something like app.use(_gMDLW) ?
Thank you
You can use app.all() to resolve this issue
Example
app.all('*', _gMDLW);
function _gMDLW(req, res, next) {
if (req.path == '/') return next();// redirect to homepage for guest
next();//authenticated user
}
You can modify it as your requirement
I want to just verify something but have't been able to find anything in the Express docs or online regarding this (although I know it's a feature).
I could just test this out but I don't really have a nice template and would like to hear from the community.
If I define a route in express like such:
app.get('/', function (req, res) {
res.send('GET request to homepage');
});
I can also define a middleware and load it directly, such as
middleware = function(req, res){
res.send('GET request to homepage');
});
app.get('/', middleware)
However, I can also chain at least one of these routes to run extra middleware, such as authentication, as such:
app.get('/', middleware, function (req, res) {
res.send('GET request to homepage');
});
Are these infinitely chainable? Could I stick 10 middleware functions on a given route if I wanted to? I want to see the parameters that app.get can accept but like mentioned I can't find it in the docs.
Consider following example:
const middleware = {
requireAuthentication: function(req, res, next) {
console.log('private route list!');
next();
},
logger: function(req, res, next) {
console.log('Original request hit : '+req.originalUrl);
next();
}
}
Now you can add multiple middleware using the following code:
app.get('/', [middleware.requireAuthentication, middleware.logger], function(req, res) {
res.send('Hello!');
});
So, from the above piece of code, you can see that requireAuthentication and logger are two different middlewares added.
It's not saying "infinitely", but it does say that you can add multiple middleware functions (called "callbacks" in the documentation) here:
router.METHOD(path, [callback, ...] callback)
...
You can provide multiple callbacks, and all are treated equally, and behave just like middleware, except that these callbacks may invoke next('route') to bypass the remaining route callback(s). You can use this mechanism to perform pre-conditions on a route then pass control to subsequent routes when there is no reason to proceed with the route matched.
As you can see, there's not distinction between a middleware function and the function that commonly handles the request (the one which is usually the last function added to the list).
Having 10 shouldn't be a problem (if you really need to).
Express version "express": "^4.17.1" or above
From the document: Series of Middleware
var r1 = express.Router();
r1.get('/', function (req, res, next) {
next();
});
var r2 = express.Router();
r2.get('/', function (req, res, next) {
next();
});
app.use(r1, r2);
Let's try a real life example:
tourController.js
exports.checkBody = (req, res, next)=>{ // middleware 1
if (!req.body.price){
return res.status(400).json({
status:'fail',
message:'Missing price!!!'
})
}
next();
}
exports.createTour = (req, res) => { // middleware 2
tours.push(req.body);
fs.writeFile(
`${__dirname}/dev-data/data/tours-simple.json`,
JSON.stringify(tours),
(err) => {
res.status(201).json({
status: 'success',
data: {
tour: newTour,
},
});
}
);
};
tourRouter.js
const express = require('express');
const tourController = require('./../controller/tourController')
const router = express.Router();
router.route('/')
.get(tourController.getAllTours)
.post(tourController.checkBody, tourController.createTour);
//muliple Middleware in post route
module.exports = router //need this or the following step will break
app.js
const express = require('express');
const tourRouter = require('./route/tourRouter');
const app = express();
app.use(express.json());
app.use('/api/v1/tours', tourRouter);
module.exports = app;
I want my logger middleware to log each matched route when response is sent. But there may be any number of nested subroutes. Let's suppose I have this:
var app = express();
var router = express.Router();
app.use(function myLogger(req, res, next)
{
res.send = function()
{
//Here I want to get matched route like this: '/router/smth/:id'
//How can I do this?
});
}
app.use('/router', router);
router.get('/smth/:id', function(req, res, next)
{
res.send(response);
});
Is it possible?
Because app-level middleware has no knowledge of routes, this is impossible. However, if you use your logger middleware as route middleware like:
router.get('/smith/:id', logger, function (req, res) { ... });
You can use a combination of two parameters on the request object:
req.route.path => '/smth/:id'
req.originalUrl => '/router/smth/123'
I'll leave it up to you how you want to combine both into one string.
Here's the code (in express 2.x)
// npm -v express
// 2.14.2
var app = express();
var router = express.Router();
app.use(function(req, res, next) {
var routes = app.routes; // See Reference 1.
for(var method in routes) {
if(routes.hasOwnProperty(method)) {
for(var route in routes[method]) {
if(req.url.toString().match(routes[method][route].regexp)) {
console.log('Route Debugger: ' + routes[method][route].path);
}
}
}
}
next();
});
app.use('/router', router);
router.get('/smth/:id', function(req, res, next)
{
res.send(response);
});
What does this do?
It queries the app.routes object. Now we have access to all the routes defined in our application.
We match the current url req.url with the regular expression of each route.
Since this is a application level middleware, it runs for every request. So you get logging like Route Debugger: /router/smth/:id, if you hit a url like /router/smith/123
Reference 1 : http://thejackalofjavascript.com/list-all-rest-endpoints/
Reference 2 : How to get all registered routes in Express?