Serve static files and app.get conflict using Express.js - node.js

I have this piece of code here:
var express = require('express')
, http = require('http')
var app = express();
var server = app.listen(1344);
var io = require('socket.io').listen(server);
app.use(express.static(__dirname + '/public'));
app.use(express.bodyParser());
app.use(express.cookieParser());
app.use(express.session({secret: 'secret'}));
app.get('/', function(req, res){
if(req.session){
console.log(req.session);
}
console.log('ok');
});
The code inside the app.get() callback is not being called. If I comment out the app.use(express.static(__dirname + '/public')) line, then the callaback works. I've tried changing the order, but its like a lottery! I would prefer to know whats going wrong here.
I'm sure this have to do with lack of knowledge from my part on how the middleware is called. Can someone help me understand this problem?
Basically I just want to perform some logic before the files are served and the index.html is load on the browser. By the way placing the app.get() before the app.use(express.static()) line, does not did the trick!

Your static file middleware should go first.
app.use(express.static(__dirname + '/public'));
app.use(express.bodyParser());
app.use(express.cookieParser());
app.use(express.session({secret: 'secret'}));
And you should be adding a use for app.router as well.
app.use(express.static(__dirname + '/public'));
app.use(express.bodyParser());
app.use(express.cookieParser());
app.use(express.session({secret: 'secret'}));
app.use(app.router);
Middleware is processed in order for each request. So if you have an index.html in your static files then requests for yourdomain.com/ will never make it to the app.router because they will get served by the static file handler. Delete index.html and then that request will flow through to your app.router.

Rename your index.html file to something else. It is that simple
app.use(express.static(__dirname + '/public'));
app.get('/', function(req, res){
if(req.session){
console.log(req.session);
}
console.log('ok');
res.sendfile(new_index_file);
});

I believe, you have 3 options here:
1) Mount your app.get('/') route (possibly, using app.router) before static middleware, so that they take precedence. Middleware that is mounted first, processes a matching request first.
2) Use a path prefix for your static paths like app.use('/static', express.static('public'));, so that statics is served from example.com/static/...
3) Want to act smart and shoot yourself in the leg? :) Sometimes people use Accept headers and content negotiation to serve 2 different content types from the same url in different circumstances. You can make your static middleware check for a specific content type in Accept header and process request, only if requests's Accept header wants a proper type. Otherwise, it will pass the processing down the stream to you / view. You can customise your static middleware content negotiation in req.accepts.

Related

express.js: Route Function not called express.js

My express.js configuration looks like this:
//app.js:
var routes = require('./routes/index');
app.use(express.static(path.join(__dirname, '../client/build'), {'index': false}));
app.use('/', routes);
//routes/index.js:
router.get('/', function(req, res) {
console.log("im never called");
});
My handler is NEVER called (should be called when requesting without path or just '/'), the browser just gets a 303 with Location //, what is wrong here?
Thanks in advance for help!
Try to add module.exports = router; to the end of routes/index.js
Edit:
There is a common practice to put all your static files in one directory (maybe you have done it already) and make all requests to static files start with /public:
app.use('/public', express.static(path.join(__dirname, '../client/build'));
Doing this way
http://yoursite.com/public/some/file.js
will be served with
../client/build/some/file.js
Instead of /public you may choose a path that will not intersect with your router.
I was having this same issue this morning and I thought I would share my solution.
The express.static method is running on all of your requests... when it cannot find a match, it can either run the next() function and continue to your desired handler or redirect to a trailing slash to check if the request is for a directory.
I fixed it by adding 'redirect:false' as follows:
app.use(express.static(
path.join(__dirname, '../client/build'),
{index: false, redirect: false}));
Reference: express.static(root, [options])

express.static middleware not looking in the specified directory (for serving static files)

I have a fairly simple setup
app.configure(function() {
app.use('/public', express.static(__dirname + '/public'));
app.use(app.router);
});
app.get('/', function(req, res) {
...
I request /somefile and expect express to look for it in /public/somefile.
But it doesn't look there.
But when I look for public/somefile directly, it does find it.
Is something wrong with my code?
It was just a cache issue. Force-reload fixed it.

Opening Page with Express

I have read around about this a lot and it seems like its an issue that confuses a lot people. I am doing a project with express and I dont want to you any tempting engines, I am using backbone with underscore and thats enough for me. I want to write plain HTML and render them..
app.configure(function(){
app.set('port', process.env.PORT || 3000);
app.set("view options", {layout: false});
app.use(express.static(__dirname + '/views'));
app.set('views', __dirname + '/views');
app.use(express.favicon());
app.use(express.logger('dev'));
app.use(express.bodyParser());
app.use(express.methodOverride());
app.use( express.cookieParser() );
app.use(express.session({ secret: 'topsecret' } ));
app.use(passport.initialize());
app.use(passport.session());
app.use(app.router);
app.use(express.static(path.join(__dirname, 'public')));
});
this is what I have so far.. I am having a hard time to understand how express knows to render the index.html file as my home page even though I have this:
app.get('/', function(req, res){
console.log("Heyyyyyy");
});
I would expect nothing to be rendered and "Heyyyy" to be printed but express renders the index.html and doesnt print "Heyyyy"
Express evaluates middleware in the order in which they are configured.
You have a static file handler before your app.router.
Take the index.html file out of the __dirname + '/views' directory.
You also have a static file handler at the bottom of your middleware stack. Static file handlers should be at the top of your middleware stack. When they're at the bottom of your middleware stack each request unnecessarily processes all of the stack. For example, you don't need to run express.bodyParser() when serving static files.

Node.js / Express.js - How does app.router work?

Before I ask about app.router I think I should explain at least what I think happens when working with middleware. To use middleware, the function to use is app.use(). When the middleware is being executed, it will either call the next middleware by using next() or make it so no more middleware get called. That means that the order in which I place my middleware calls is important, because some middleware depends on other middleware, and some middleware near the end might not even be called.
Today I was working on my application and had my server running in the background. I wanted to make some changes and refresh my page and see the changes immediately. Specifically, I was making changes to my layout. I couldn't get it to work so I searched Stack Overflow for the answer and found this question. It says to make sure that express.static() is beneath require('stylus'). But when I was looking at that OP's code, I saw that he had his app.router call at the very end of his middleware calls, and I tried to figure out why that was.
When I made my Express.js application (version 3.0.0rc4), I used the command express app --sessions --css stylus and in my app.js file the code came setup with my app.router above both the express.static() and require('stylus') calls. So it seems like, if it comes already setup that way, then it should stay that way.
After re-arranging my code so I could see my Stylus changes, it looks like this:
app.configure(function(){
//app.set() calls
//app.use() calls
//...
app.use(app.router);
app.use(require('stylus').middleware(__dirname + '/public'));
app.use(express.static(__dirname + '/public', {maxAge: 31557600000}));
});
app.get('/', routes.index);
app.get('/test', function(req, res){
res.send('Test');
});
So I decided that the first step would be to find out why it is important to even have app.router in my code. So I commented it out, started my app and navigated to /. It displayed my index page just fine. Hmm, maybe it worked because I was exporting the routing from my routes file (routes.index). So next I navigated to /test and it displayed Test on the screen. Haha, OK, I have no idea what app.router does. Whether it is included in my code or not, my routing is fine. So I am definitely missing something.
So Here Is My Question:
Could somebody please explain what app.router does, the importance of it, and where I should place it in my middleware calls? It would also be nice if I got a brief explanation about express.static(). As far as I can tell, express.static() is a cache of my information, and if the application can't find the requested page, it will check the cache to see if it exists.
Note: This describes how Express worked in versions 2 and 3. See the end of this post for information about Express 4.
static simply serves files (static resources) from disk. You give it a path (sometimes called the mount point), and it serves the files in that folder.
For example, express.static('/var/www') would serve the files in that folder. So a request to your Node server for http://server/file.html would serve /var/www/file.html.
router is code that runs your routes. When you do app.get('/user', function(req, res) { ... });, it is the router that actually invokes the callback function to process the request.
The order that you pass things to app.use determines the order in which each middleware is given the opportunity to process a request. For example, if you have a file called test.html in your static folder and a route:
app.get('/test.html', function(req, res) {
res.send('Hello from route handler');
});
Which one gets sent to a client requesting http://server/test.html? Whichever middleware is given to use first.
If you do this:
app.use(express.static(__dirname + '/public'));
app.use(app.router);
Then the file on disk is served.
If you do it the other way,
app.use(app.router);
app.use(express.static(__dirname + '/public'));
Then the route handler gets the request, and "Hello from route handler" gets sent to the browser.
Usually, you want to put the router above the static middleware so that a accidentally-named file can't override one of your routes.
Note that if you don't explicitly use the router, it is implicitly added by Express at the point you define a route (which is why your routes still worked even though you commented out app.use(app.router)).
A commenter has brought up another point about the order of static and router that I hadn't addressed: the impact on your app's overall performance.
Another reason to use router above static is to optimize performance. If you put static first, then you'll hit the hard drive on every single request to see whether or not a file exists. In a quick test, I found that this overhead amounted to ~1ms on an unloaded server. (That number is much likely to be higher under load, where requests will compete for disk access.)
With router first, a request matching a route never has to hit the disk, saving precious milliseconds.
Of course, there are ways to mitigate static's overhead.
The best option is to put all of your static resources under a specific folder. (IE /static) You can then mount static to that path so that it only runs when the path starts with /static:
app.use('/static', express.static(__dirname + '/static'));
In this situation, you'd put this above router. This avoids processing other middleware/the router if a file is present, but to be honest, I doubt you'll gain that much.
You could also use staticCache, which caches static resources in-memory so that you don't have to hit the disk for commonly requested files. (Warning: staticCache will apparently be removed in the future.)
However, I don't think staticCache caches negative answers (when a file does not exist), so it doesn't help if you've put staticCache above router without mounting it to a path.
As with all questions about performance, measure and benchmark your real-world app (under load) to see where the bottlenecks really are.
Express 4
Express 4.0 removes app.router. All middleware (app.use) and routes (app.get et al) are now processed in precisely the order in which they are added.
In other words:
All routing methods will be added in the order in which they appear. You should not do app.use(app.router). This eliminates the most common issue with Express.
In other words, mixing app.use() and app[VERB]() will work exactly in the order in which they are called.
app.get('/', home);
app.use('/public', require('st')(process.cwd()));
app.get('/users', users.list);
app.post('/users', users.create);
Read more about changes in Express 4.
Routing means determining how an application responds to a client request to a particular endpoint, which is a URI (or path) and a specific HTTP request method (GET, POST, and so on).
Each route can have one or more handler functions, which are executed when the route is matched.
In Express 4.0 Router, we are given more flexibility than ever before in defining our routes.
express.Router() is use multiple times to define groups of routes.
route used as middleware to process requests.
route used as middleware to validate parameters using ".param()".
app.route() used as a shortcut to the Router to define multiple requests on a route
when we are using app.route(), we are attaching our app with that router.
var express = require('express'); //used as middleware
var app = express(); //instance of express.
app.use(app.router);
app.use(express.static(__dirname + '/public')); //All Static like [css,js,images] files are coming from public folder
app.set('views',__dirname + '/views'); //To set Views
app.set('view engine', 'ejs'); //sets View-Engine as ejs
app.engine('html', require('ejs').renderFile); //actually rendering HTML files through EJS.
app.get('/', function (req, res) {
res.render('index');
})
app.get('/test', function (req, res) {
res.send('test')
})
In express Version 4 we can easily define routes in the following manner:
server.js:
const express = require('express');
const app = express();
const route = require('./route');
app.use('/route', route);
// here we pass in the imported route object
app.listen(3000, () => console.log('Example app listening on port 3000!'));
route.js:
const express = require('express');
const router = express.Router();
router.get('/specialRoute', function (req, res, next) {
// route is now http://localhost:3000/route/specialRoute
});
router.get('/', function (req, res, next) {
// route is now http://localhost:3000/route
});
module.exports = router;
In server.js we imported the router object of the route.js file and apply it in the following manner in server.js:
app.use('/route', route);
Now all of the routes in the route.js have the following base URL:
http://localhost:3000/route
Why this approach:
The main advantage of taking this approach is that now our app is more modular. All the route handlers for a certain route now can be put into different files which makes everything more maintainable and easier to find.
An article by #kelyvinn from 2016, with the intent to demonstrate modularity, includes this code:
// controllers/apis/dogs/index.js
const
express = require('express'),
dogService = require('../../../services/dogs');
let router = express.Router();
router.get('/', dogService.getDogs);
router.get('/:id', dogService.getDogWithId);
module.exports = router;

Express.js: how to make express.static have higher priority than the rest of the app?

I have an express.js app set up like this:
app.use(express.static(__dirname + '/public'));
...
app.all('*', require('./routes/all'));
So when I try to load /stylesheets/style.css, request is dispatched to the routes. How do I make the app first try to use "static", and then - the catch-all route?
Middleware get executed in sequential order. Simply put the static middleware before the routing middleware.
app.configure(function() {
app.use(express.static(__dirname + '/public'));
app.use(app.router);
});

Resources