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I have been reading documents/urls and really not understand about app.use and its usage. I understand that it is part of connect but I am really not getting that.

Example:

// ignore GET /favicon.ico app.use(express.favicon()); // add req.session cookie support app.use(express.cookieSession()); // do something with the session app.use(count);

can you please explain me all these 3 . what they mean? does this mean based on (1) that app.use is noting but => app.get? app.use(count) what and when is this count be executed (or) called/

Looks Basic but did not get the answers

// ignore GET /favicon.ico app.use(express.favicon()); // pass a secret to cookieParser() for signed cookies app.use(express.cookieParser('manny is cool')); // add req.session cookie support app.use(express.cookieSession()); // do something with the session app.use(count); // custom middleware function count(req, res) {
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When you call app.use(), you pass in a function to handle requests. As requests come in, Express goes through all of the functions in order until the request is handled.

express.favicon is a simple function that returns favicon.ico when it is requested. It's actually a great example for how to get started with this pattern. You can view the source code by looking at its source: node_modules/express/node_modules/connect/lib/middleware/favicon.js

express.cookieSession is some more middleware for supporting session data, keyed from the client by a cookie.

I don't know what count does... is that your own code? In any case, let me know if this is not clear.

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Thank you for the explanation. so "app.use(), you pass in a function to handle requests" so in my examples I have no request only the function to be called . so it will take it default "GET"??? ..yes count is a userdefined function as function count(req, res). can you please explain when app.use(express.cookieSession()); is called? my question here is there is no req. so on what basies that will be called
What do you mean? You're not using Express to handle HTTP requests? Middleware loaded up with app.use will be called no matter what the request is. That doesn't mean it will always act on the request... it's up to the middleware to decide whether to handle the request or let the next function handle it.
I have updated the question with a sample program. my question is when a Request comes which "app.use" should be called. I see that in my case it always calls app.use(count) . I am asking why not : app.use(express.cookieSession());
They are all called, in order that they were set up with app.use, until one piece of middleware decides to handle the request. Your express.cookieSession is being called if you are reaching count. See also: stackoverflow.com/a/8711139/362536
Yes, that's correct. It is up to the middleware to decide whether or not to call the next function. Middleware, such as the cookie handlers you have, will always call the next function.
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