I have multiple routes, split into different files (my app consists of different "modules", which I maintain in separate folders. For each folder, there is an index.js file in which I manage the routes per module, and I require these in the app.js file).
For every route, I will require to check the auth, and pass the loggedIn status to the header of every page:
//Default variables for the ejs template
var options = {
loggedIn: true
};
res.render("home/home", options);
If the logged in status is true, then the user's name will be displayed. If not, the login / signup labels are displayed.
What is the best way to centralise this, so that I don't need to require the auth script in every of these index.js (route) files?
I need to be able to pass the auth status to the view via the options object (see example).
In your auth, module, use a middleware function. That function can check and store res.locals.loggedIn which will be available for any view that will eventually be rendered. Just make sure the app.use call executes prior to your other routes and it will work properly.
app.use(function auth(req, res, next) {
res.locals.loggedIn = true; // compute proper value here
next();
});
From what I understand you need to do this for every request.One common thing is adding this as middleware so that all the request gets this .
For Example :
var http = require('http');
var connect = require('connect');
var app = connect();
app.use(function(req, res) {
res.end('Hello!');
});
http.createServer(app).listen(3000)
Now for every request , Hello is printed . You could extract this as a module and reuse it across projects. Check here for more details
Related
In my express application I have a module called helpers thats is required in almost all my routes and modules. This module has a logger method that logs to fluentd (but that's unimportant). While building the data to log I'd like to add a unique identifier of the request, so that all the logs written for the same request have the same unique ID. Using a global var in the app entry point app.use doesn't work because this var would be overwritten every time a new request hits, so the global uuid will change would obviously change in case of high load or long running tasks. The res.locals is not available outside routing, so I can't use it for this matter. Is there a way to create a var that would be unique per request and available in every module or maybe a way to access the res.locals data outside routing? Thank you
EDIT
Maybe an example will help understand better the question.
Suppose I have a module called helpers.js like this:
let helpers = {};
helpers.log = (logData, logName) => {
fluentLogger.emit('', {
name: logName,
//uuid: the needed uuid,
message: logData
});
}
module.exports = helpers;
Now obviously I can do this in my app.js entry point:
app.use(function (req, res, next) {
res.locals.uuid = uuid.v4();
next();
});
and then in every loaded middleware module that requires helpers(adding a new param to the helpers.log method):
const helpers = require('helpers');
router.post('/', (req, res, next) => {
helpers.log('my log message', 'myLogName', res.locals.uuid);
next();
});
and this will normally work. But suppose a big or middle size project where there are hundreds of custom modules and models (not middlewares) and a module may require other modules that require other modules that require finally the helpers module. In this case I should pass the res.locals.uuid as a parameter to every method of every method so that I have it available in the logger method. Not a very good idea. Suppose I have a new module called dbmodel.js that is required in a middleware function:
const helpers = require('helpers');
let dbmodel = {};
dbmodel.getSomeData = (someParam) => {
//some logic
helpers.log('my log message', 'myLogName');
}
module.exports = dbmodel;
The dbmodel has no idea about the res.locals data if I don't pass it from the middleware, so the helpers.log method will also have no idea about this.
In PHP one would normally write a GLOBAL var in the application's entry point so a hypothetical logger function would have access to this global on every method request from whichever class of the application.
Hope this explanation will help :) Thank you
EDIT 2
The solution for this kind of problems is CLS. Thanks to #robertklep for the hint. A good slideshare explaining exactly the same problem (logger with unique ID) and explaining the CLS solutions can be found here: https://www.slideshare.net/isharabash/cls-and-asynclistener
I answered a very similar question here which will solve this problem.
I used to solve the problem the libraries node-uuid and continuation-local-storage. Take a look to the answer of this question and see if it helps:
NodeJS Express - Global Unique Request Id
And you want a bigger explanation, take a look here:
Express.js: Logging info with global unique request ID – Node.js
Yes you can do so by one method .
Every request comes to his routes pass that request inside the middleware.
Suppose you have
app.get('/', function(req, res) {
res.sendFile(path.join(public + "index.html"));
});
a request.
Place Middleware in it .and edit req field coming , in this way you will get the unique variable values for each request
check out this .
https://expressjs.com/en/guide/writing-middleware.html
Like this
var requestTime = function (req, res, next) {
req.requestTime = Date.now()
next()
}
app.use(requestTime)
app.get('/', function (req, res) {
var responseText = 'Hello World!<br>'
responseText += '<small>Requested at: ' + req.requestTime + '</small>'
res.send(responseText)
})
Here req.requestTime is unique for each request.
I am working on a university project and we have decided to go for MEAN technology stack. To be honest I am a beginner with NodeJS and express, more precisely this is the first time I do sth with it.
I've found that is preferable to use express.Router rather than putting all routes to express instance e.g. app.post('path', function(req, res) { ... })
So this is what I have
var express = require('express');
var app = express();
function authorizationMiddleware(req, res, next) {
...
}
// handles login, doesn't meed autorizationMiddleware
var authRouter = express.Router();
authRouter.route('/login')
.post(function (req, res) {
...
});
// handles fetching of a single, all person(s), fetching of transactions for a person
var personRouter = require('./routes/personRoutes')(Person, Transaction, autorizationMiddleware);
//handles adding of a new transaction e.g. POST /api/transactions where params such as sender, recipient and amount are passed in body
var transactionRouther = require('./routes/transactionRoutes')(Person, Transaction, autorizationMiddleware);
app.use('/api', authRouter);
app.use('/api/persons', personRouter);
app.use('/api/transactions', transactionRoutes);
app.listen(8080, function () {
console.log('Listening on port: ' + 8080);
});
As you can see I have three routers (not even sure if I have gonne too far with them), authRouter is handling login only and I have also decided to separate persons logic from transactions logic too. (maybe I could have handled creation of new transaction in a way like /api/persons/:personId/transactions but I rather liked the idea of sending all required params in body).
I would like to ask if you agree with the solution I tried. As you can see I am passing authrizationMiddleware function (handles verification of JWT token) function to router modules and using it there.
Is there maybe a better way to use the same middleware with of multiple routers or is this a legit way?
Thx in advance
Cheers!
I don't get why you use 3 Routers. The "common" way to go (or at least the way I go) is to put all the routes in the same place, except when the path is very different or the purpose is different (for example I separate the error routes from the others).
For example, let's say I need to build a rest api for an app, I would probably have paths like:
/users/:userid
/users/:userid/comments/:commentid
/locations
...
All these routes can go in the same Router and if you want, you can apply specific authentication/authorization middlewares to them:
router.get("/users/:userid",
doAuthentication, authorizeOnUserId,
userController.getUserById);
router.get("/locations",
doAuthentication, authorizeLocations,
locationController.getAllLocations);
The middlewares are called in sequence and the request is passed on to the next middleware only if there are no errors (unauthenticaed/ unhauthorized).
Then you can simply import your routes like this:
app.use('/api', router);
Using this technique allows you to have a fine grain control over your routes.
Hope this helps.
I'm trying to add a new route (/profile) to my NodeJS Express web application. I've modified my app.js file like this:
var routes = require('./routes/index');
var profile = require('./routes/profile');
app.use('/', routes);
app.use('/profile', profile);
The '/' index path works fine, my issue is with '/profile'. Whenever I try to access it, I get a 404. This is profile.js:
var express = require('express');
var router = express.Router();
router.get('/profile', function(req, res) {
var username = req.session.username;
if(username) {
res.render('profile');
} else {
res.redirect('/login');
}
});
module.exports = router;
I don't understand what I'm doing wrong because in the example express application that is generated, '/users' works fine. I basically copied that format, but it's throwing a 404. Any ideas?
In my profile.js, I had to change my GET request path to this:
router.get('/', function(req, res) {
//code
});
Otherwise, the router would be looking for /profile/profile. When I change it to /, it's just looking for the root of `/profile', or at least that's how I understand it.
To understand what you are doing wrong you should know that Node.js uses middleware functions to route your requests. To simplify you can think about it as a chain of functions.
Middleware is like a plumbing pipe, requests start at the first middleware you define and work their way “down” the middleware stack processing for each path they match.
So with the following statement you added a middleware function to handle any request starting with the root path /profile, and it is a common pattern in Node to use the use method to define the root paths.
app.use('/profile', profile);
The use method is doing part of the routing in your scenario and the statement above will match any route starting with that path, including /profile/all or /profile/12 or even /profile/go/deeper/inside.
However, you want to narrow down that routing to something more specific, so that is why you pass a router middleware function (profile in your case) to match more specific routes instead of all routes starting with /profile.
The profile middleware function is actually the next step in the chain of functions to execute, and it will start from the root path specified in the use statement, which is the reason why you need to start again with / and not with /profile. If you wanted to match a profile by ID you would do:
router.get('/:id', ...)
Which would be concatenated with the base URL (from the /use statement) and would match a request like /profile/2 or /profile/abc.
I am very new to Node.js, and I was wondering if that, except for session(), I could use a "storage" to store variables for the current request?
I have an API which is based on an Authorization header, and a pool of valid tokens stored in Redis.
Therefore I don't have a session and don't want to.
But I would like to store variables for further use during this request. For example, I would like to store the user_id corresponding to the token found in Redis, so that I can use it wherever I want.
If I do something like:
app = express();
app.user_id = 1;
Is it ok, or will my user_id become global to all requests handled by the app? (in short: is the app instanciated for each request handled by the server, or is it persistent?)
If this is not ok, how could I achieve something like this without sessions?
Thank you for any help :)
The app handles all requests, and would only be created once on startup, but req lives for only the lifetime of the request. Keep in mind that the req in Express is just an object, and as such, can be assigned values. So if you wanted to allow the controller to have access to some value (similar to sessions), you could do something like this:
var express = require('express');
var app = express();
// middleware that assigns a value '123' to 'req.user_id'
app.use(function(req, res, next) {
req.user_id = 123;
next();
});
// controller which responds with the 'req.user_id'
app.get('/hello', function(req, res){
res.send('req.user_id: ' + req.user_id); // responds with req.user_id: 123
});
app.listen(3000, function() {
console.log('Listening on port 3000');
});
In the above example, the middleware that I created assigns a value to the request, called user_id. This value lives for the life of the request. You could do a similar thing to assign a dynamic value to the req so that you can access it via your controllers.
With an express app running on a node server, how would I go about recursively searching for a render file from the full path right back to the beginning of the supplied URL.
For example, if someone was to hit my server with www.somewebsite.com/shop/products/product, the render engine would first check that there is an index.jade file in shop/products/product/. If none is found it would then check shop/products/, and subsequently shop/.
var express = require('express');
var app = express();
app.get('/*', function(req, res){
res.render(req.path + '/index.jade', function(err, html){
// some loopback code which alters the path and recalls the render method
})
});
The problem is that the response object is not passed to the render callback, so I'm unable to recall render on the response. I'm looking to create a loop because the URL paths may be any number of directories deep, so I can't just assume I only need to cascade for a definitive number of times.
Anyone see a way round this?
You should be able to use the response object from the closure. I think (assuming express allows you to call res.render a second time) you could use code like this answer to achieve what you want:
var express = require('express');
var app = express();
app.get('/*', tryRender);
function tryRender(req, res){
res.render(req.path + '/index.jade', function(err, html){
if (err) {
req.path = 'mynewpath';
tryRender(req, res);
}
})
}
Note: You will need to add a base case or this function will recurse infinitely if it doesn't find a view that works :D
In the event that express doesn't allow a subsequent call to res.render, you'll probably need to find out if the file exists on the file system yourself.