I am new with node and am trying to figure out dynamic routing. I have routes already set up such as
app.route('/users')
.get(dbController.collect)
.post(dbController.insert);
app.route('/users/:userId')
.get(dbController.read)
.put(dbController.update)
.delete(dbController.delete);
I want to be able to do something similar for routes that I have not defined in my code while still letting the routes I have defined work as usual. For example if someone was to send a get request to https://example.com/books/12 it would dynamically run the read function as it does for users.
Express routing allows you to do catch-all routes:
app.all('*', (req, res) => {
console.log('Route is unknown')
// Do something here...
})
Related
I've created a NodeJS Express app. But my express route is invocking multiple routes function, one after another, but I only need one at a time.
My express app.js
app.use(routes)
Express router:
const router = express.Router();
router.post("/product", controller.productFunction)
router.post("/user", controller.userFunction)
router.get("/:id", idController.getId)
Whenever I create a post request for "/product" route, first the productFunction is invocked, but then the "/:id" routes getId function is also get invocked. Same thing happen for /user route as well. Always /:id route is getting invocked.
Is there any way to prevent this?
I even tried this way, but after the homepage loading then again it invockes getId function.
app.get("/", (req, res, next) => {
res.sendFile(..........);
});
app.use(routes);
I am sure that this is not an issue with the router itself.
You can't skip from POST to GET handling. So invocations are caused by different requests.
router.get("/:id", idController.getId) kind of wild card, and <server_url>/favicon.ico will trigger it
If you check it via browser it tries to get favicon or smth else and invokes this handler.
Try to make POST request via curl/Postman and idController.getId should not be called.
It is risky to serve static and process requests on a same level.
You can add some prefix to all your request, like that app.use('/api', routes); then static file will be available on /<file_name> and all server logic will be under /api/<request>
In my NodeJs/express based application, I am authorizing calls to all the endpoints by using the following middleware.
app.use(restrictByCookieMiddleware);
I want to authorize all endpoints except one i.e. I don't want "restrictByCookieMiddleware" middleware to run for "/metrics" endpoint. Is there a way to escape one endpoint?
Here, I found some examples that matches endpoint for which middleware should run, I am looking for a solution that skips one.
Your have a couple of choices:
First, you can just define the one exception route handler BEFORE the middleware. Then, it will handle that route and the routing will never get to the middleware.
app.get("/login", (req, res) => {
// handle that one special route here
});
// all other routes will get this middleware
app.use(restrictByCookieMiddleware);
Second, you can make a wrapper for the middleware that compares to the one specific route and skips the middleware if it's that route:
app.use((req, res, next) => {
// shortcircuit the /login path so it doesn't call the middleware
if (req.path === "/login") {
next();
} else {
restrictByCookieMiddleware(req, res, next);
}
});
// then, somewhere else in your code would be the /login route
app.get("/login", ...);
Third, if you have multiple routes that you want to skip the middleware for, you can segment things by router. Create a router for the non-middleware routes and put all of them on that router. Hook that router into the app object first.
Then, create a second router that contains the middleware and has all your other routes on it.
Place that specific route, you want to exclude, before this line:
app.use(restrictByCookieMiddleware);
So this will solve your problem.
I have a Node.js restful API. The problem I am having is that I am not sure why I am not able to see the request headers inside the middleware route.use(), however, it is visible inside get method router.get('/',function(req,res){}).
Can you someone please why is this case or what do I have to do get it visible inside
router.use(function(req,res,next){ next();});
Try something like his
router.use(function (req, res, next) {
console.log(req.headers['header_name']);
if (!req.headers['header_name']) return next('router')
next()
})
To skip the rest of the router’s middleware functions, call next('router') to pass control back out of the router instance.
I'm doing an API in nodejs with express as router.
Now i'm trying to implement an client-id and an apikey to add some security to the API, and the problem that i'm facing is the next:
One of my API call is like this:
router.get("roles/get-objects/:mail/:filter*?")
So this means, that i can request an object like this:
/roles/get-objects/mail#mail.com/customer
Now the tricky part begins... when I needed to stablish a middleware to read an client-id and an apikey to verify that the client is authorized to se the API, so I did this:
In the declaration of the middleware, I use this wildcard:
router.all('/*', function (req, res, next) {
XXXX})
The thing is, I have tried in the middleware, as a wildcard everything...
I want that any API call is filtered thru that middleware, but apparently I can't find the right wildcard for it...
When I use /roles/* as wildcard, if I do a request to /roles it does work, but when I use the complete URL like: /roles/get-objects/mail#mail.com/customer it doesn't go thru my middleware.
So anybody has any idea? i'm starting to loose my mind
Thank you so much to all of you!
EDIT:
Now i'm using this middleware declaration:
router.use(function (req, res, next) {XXXX})
So when I call:
/roles/get-objects/
It's executed, the problem is when I add the email to the route:
/roles/get-objects/mail#mail.com
The app goes directly to the route that i have for that, but omits my middleware:
router.get("roles/get-objects/:mail",
I don't understand why is this happening, apparently everything should go thru my middleware first, or am I wrong?
If you want to establish a middleware to check all HTTP request whose URL starting with /roles/, the middleware should be placed before any other specific router definition:
router.use('/roles', function(req, res, next) {...});
...
router.get('/roles/get-objects/:mail', ...);
If the middleware is defined after specific route, when HTTP request comes in, the specific route is targeted and processed, the middleware won't be executed any more:
router.get('/roles/get-objects/:mail', ...);
...
router.use('/roles', function(req, res, next) {...}); // This middleware logic won't execute when request is sent to '/roles/get-objects/some-email', as the request has already been handled and response is already sent to browser.
I was just reading the documentation on express and found these two terms, app.use(); and router.use();
I know app.use(); is used in node for Mounting a middleware at a path, and we often use it in most of the node apps. but what is router.use(); are they both same? if not, whats the difference ?
I read about router here. I also found similar questions on SO What is the difference between "express.Router" and routing using "app.get"?
and Difference between app.all('*') and app.use('/'), but they do not really answer my question. Thanks.
router.get is only for defining subpaths. Consider this example:
var router = express.Router();
app.use('/first', router); // Mount the router as middleware at path /first
router.get('/sud', smaller);
router.get('/user', bigger);
If you open /first/sud, then the smaller function will get called.
If you open /first/user, then the bigger function will get called.
In short, app.use('/first', router) mounts the middleware at path /first, then router.get sets the subpath accordingly.
But if we instead use the following:
app.use('/first', fun);
app.get('/sud', bigger);
app.get('/user', smaller);
If you open /first in your browser, fun will get called,
For /sud, bigger will get called
For /user, smaller will get called
But remember for /first/sud, no function will get called.
This link may also help: http://expressjs.com/api.html#router
router.use(); mounts middleware for the routes served by the specific router, app.use(); mounts middleware for all routes of the app (or those matching the routes specified if you use app.use('/ANYROUTESHERE', yourMiddleware());).
Example use case could be an app with one router with standard routes and one router that handles api routes, which need a valid user.
You would then mount the authentication middleware for the api router only with router.use(yourAuthMiddleware());.
If you would have an app though that requires a valid user for all routes, mount the middleware for the app with app.use(yourAuthMiddleware());
app.use() used to Mounts the middleware function or functions at the specified path,the middleware function is executed when the base of the requested path matches path.
router.use() is used to middleware function or functions, The defaults mount path to “/”.
But in
app.use() you will have to give a specified path like that:
var adsRouter = require('./adsRouter.js');
app.use('/ads', adsRouter);
or
app.use('/ads', function(req, res, next) {
// write your callback code here.
});
But while using router.use() you can give only middleware, like this:
router.use(function(req, res, next) {
console.log('%s %s %s', req.method, req.url, req.path);
next();
});
or
router.use('/test', function(req, res, next) {
// write your callback code here.
next();
});
or
//in router.js
router.use('/admin', authUtil.verifySessionId, authUtil.verifyLisencee);
router.post('/admin', controllerIndex.ads.adListingAdmin);
In the above code when the end point is '/admin' then first it will call the authUtil.verifySessionId and authUtil.verifyLisencee then it will execute next line with 'admin' end point and according to controllerIndex.ads.adListingAdmin method.
app.use(middleware): application-level middleware.
router.use(middleware): router-level middleware.
("middleware" refers to methods/functions/operations that are called between processing the request and sending the response.)
See https://expressjs.com/en/guide/using-middleware.html for a comparison of different types of middleware used in an Express app.
When looking at the express js docs for Routing (https://expressjs.com/en/guide/routing.html#express-router):
Use the express.Router class to create modular, mountable route handlers. A Router instance is a complete middleware and routing system; for this reason, it is often referred to as a “mini-app”.
A Router created with express.Router() is no different than an app created with express() in terms of functionality; it's like a logical grouping of routes/handlers/services/databases/etc. The biggest difference is the scope that it affects. A router just affects its own scope while the app is like the master/global scope for your web/app server. You could have many routers or "apps" running on one main app/web server instance. This is why you could listen to requests on an app instance via app.listen(80) but not on a router.