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app.set and then TypeError: app.get is not a function

While using express 4.x, I am setting the port in my server.js like in the following.
var express = require('express');
var app = express();
...
var port = process.env.PORT || 8080;
app.set('port', port);
...
module.exports = app;
But when I try to access it within my routes file, like the following...
// path to routes file is app/models, hence the '../../'
var app = require('../../server');
// default route
router.get('/', function (req, res) {
res.send('Hello! The API is at http://localhost:' + app.get('port') + '/api');
});
... I get the following error.
TypeError: app.get is not a function
What on earth is going on?

Okay, I have finally figured it out. The app was not properly being set within the routes file because we were previously doing module.exports = app after require('./app/models/routes'); within server.js. So as soon as I moved the exporting of the app to happen before the requiring of the routes file... everything worked!

I don't know exactly what's going on and I don't know if you would like this solution. I had a similar problem as this once.
in the main file i did something like
var express = require('express');
var app = express();
....
var routes = require("./routes/path")
routes(app);
and in routes i did something like
in where you have "./routes/path" file:
module.exports = function(app){
//I got access to app.locals
}
you see I passed along the express app .
basically routes is a function that takes app as a parameter.
I tried app.set("app", app) and I don't think that worked.

It looks like app is not being defined. you could also try something like this.
router.get('/', function (req, res) {
var app =req.app.get("app")
res.send('Hello! The API is at http://localhost:' + app.get("port") + '/api');
});
https://stackoverflow.com/a/15018006/1893672

In your route handling for GET, POST, etc, you should be receiving the 'req' dependency. App should be attached to this so just reference req.app:
router.get('/',function(req,res,next){
console.log(app.get('secret'));
}
No require statement should be necessary.

app.post is not a function express node

I had all my routes in server.js but I wanted to make it modular and put into a folder called routes. I created a file called apis.js in routes folder but as I did that I get TypeError: app.post is not a function
server.js:
var express = require('express');
var app = express();
var bodyParser = require('body-parser');
var urlencode = bodyParser.urlencoded({ extended: true});
app.use(express.static('public'));
var apis = require('./routes/apis');
app.use('/', apis);
module.exports = app;
apis.js:
module.exports = function(app){
app.get('/', function(req, res) {
res.send('OK');
});
app.post('/idea', function(req, res) {
...
});
};
Also, having module.exports = app in server.js is important as I have tests running and I want a instance of app everytime.
What am I missing?

Better approach :-
server.js
var express = require('express');
var app = express();
var bodyParser = require('body-parser');
var urlencode = bodyParser.urlencoded({ extended: true});
app.use(express.static('public'));
var apis = require('./routes/apis');
app.use('/', apis);
module.exports = app;
apis.js :-
var router = require('express').Router();
router.post('/url',function(req,res,next){
//your code
})
module.exports = router

You need to pass in your express app into your apis module so it can attach the routes to your app. If you want to use app.use to put your routes in a different root path, you can create another express router, and attach your routes to that, then app.use that router:
server.js:
var express = require('express');
var app = express();
var bodyParser = require('body-parser');
var urlencode = bodyParser.urlencoded({ extended: true});
app.use(express.static('public'));
var apis = express.Router();
require('./routes/apis')(apis);
app.use('/', apis);
module.exports = app;

There's a couple different methods for connecting your app to your routes, and it looks to me like you are mixing them together, resulting in your error.
The fix already mentioned...
var router = require('express').Router();
router.post('/url',function(req,res,next){
//your code
})
module.exports = router
...works with the way you currently have your server.js file set up.
Another method that doesn't require you to modify your apis.js file is to require it in server.js using
require("./routes/apis.js")(app);
instead of
var apis = require('./routes/apis');
app.use('/', apis);
This ensures that the variable app is passed into the function in apis.js
The first version is recommended, but hopefully this explains why you are getting confused between the two, i.e. because the second is an alternate version.
See Differences between express.Router and app.get? for more information on why the router version is recommended.

Module.Exports not working for Express

I'm trying to organize routes in express. But I'm having trouble getting a simple setup to work. I have two files, api.js, which has the routing info, and index.js, which runs the server.
However, when I try this, I get no response on localhost:3000.
api.js
var express = require('express');
module.exports = function() {
var router = express.Router();
router.get('/', function(req, res) {
res.send('im the home page!');
});
return router;
}
index.js
var express = require('express');
var app = express();
var router = require('./api');
app.use('/',router);
app.listen(3000);
console.log('Listening on port 3000!');
However, when I change api.js to this, it works:
api.js
var express = require('express');
var router = express.Router();
router.get('/', function(req, res) {
res.send('im the home page!');
});
module.exports = router;
I don't understand why the bottom api.js works when the top one doesn't. Shouldn't module.exports return the same express Router in both cases?

The difference is that in the first version you're exporting a function that returns the router vs the second version where you're exporting the router itself.
In the first version, Express calls your exported function, passing it req and res, expecting it to somehow handle the request. The exported function of course is not designed to handle a request (it's just creating a router and returning it), so the request times out.

Express and Cheerio/JSDOM

I am trying to get Cheerio to work with Express.
I'd like to be able to manipulate the dom from the server, but all I have found is web scraping..
There are some requirements..
At the moment, I am able to run multiple app.listen(port); statements, and use multiple servers.
I'm trying to append <script>alert("test);</script> to every single page sent by express.
I've created the express server: (Assuming Path is a predefined variable)
var express = require('express');
var app = express();
app.get('/', function (req, res) {
app.use(app.static(Path));
res.sendFile(Path + "/index.html");
});
app.listen(Port);
Can you guys provide me with a working example to append this to the page. Is there a way to get this to work in real time?
Thanks!

Here's a quick/simple example with no error handling:
var express = require('express');
var fs = require('fs');
var cheerio = require('cheerio');
var app = express();
app.get('/', function (req, res) {
fs.readFile(Path + '/index.html', function(err, data) {
var $ = cheerio.load(data);
$('body').append('<script>alert("test");</script>');
res.send($.html());
});
});
app.listen(Port);
I just tested that locally and it worked as expected. Be sure to test err inside the readFile callback in your real implementation and handle things appropriately if the file isn't found or there's an error reading it.

app.get is not working for base route

I am an absolutely newby in node.js and I try to create a new project via this technology. I use express framework but on the start I have a little trouble. I have solved this trouble with workaround but I have a question for next behavior:
My app.js
var express = require('express')
, routes = require('./routes/index')
, routes = require('./routes/login');
var app = module.exports = express.createServer();
console.log(app.env);
// Configuration
app.configure(function(){
app.set('views', __dirname + '/views');
app.set('view engine', 'ejs');
app.use(express.bodyParser());
app.use(express.methodOverride());
app.use(app.router);
app.use(express.static(__dirname + '/public'));
});
app.configure('development', function(){
app.use(express.errorHandler({ dumpExceptions: true, showStack: true }));
});
app.configure('production', function(){
app.use(express.errorHandler());
});
// Routes
app.use( function(req, res, next) {
if (req.url == '/') {
res.render('index', { title: 'Express!' })
} else {
next();
}
});
//app.get('/', routes.index);
app.get('/login', routes.login);
app.listen(3000, function(){
console.log("Express server listening on port %d in %s mode", app.address().port, app.settings.env);
});
In a block // Routes you can see app.use and app.get. If I try to use app.get instead of app.use I get error "cannot get /". I tried to put index.html file to my public folder. But fot "/" route I everytime got this file, not render of index.js.
app.get('/login', routes.login); - is work fine, but something wrong with "/" route. I dont want to leave my code in this state, please, help me understand this behavior.
Thank in advance.

Like the user PA. mentioned, the reason your code never finds the / url, is because you are redeclaring your routes variable:
var express = require('express')
, routes = require('./routes/index') // first declaration of 'routes'
, routes = require('./routes/login'); // re-declaration of 'routes'
This makes your first routes declaration (the declaration that was pointing to /index) unreachable by your code, which is why you get the error "cannot get /", because your routes variable only points to ./routes/login.
There are a few ways you can fix this to clean up your code:
1. Assign different variables for the different routes:
var express = require('express')
, index = require('./routes/index')
, login = require('./routes/login');
- 0R -
2. Put multiple functions in the routes file:
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~
// in your routes/index file
exports.index = function(req, res){
res.render('index', { title: 'Index Page' });
};
exports.login = function(req, res){
res.render('login', { title: 'Login Page' });
};
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~
// in your app.js file
// import your 'routes' functions from your 'routes' file
var express = require('express')
, routes = require('./routes/')
// now use your routes functions like this:
app.get('/', routes.index);
app.get('/login', routes.login);
- OR -
In a large application, or for better code maintainability, you may want to break up your different routing functions into different files (instead of putting all your routing functions in one file, like the example above), so using the express default setup as an example, they are placing their user functions and their index functions in the routes folder this like:
routes /
user.js
index.js
Then, they setup their application like this:
var routes = require('./routes');
var user = require('./routes/user');
And call these functions like this:
app.get('/', routes.index); // calls the "index" function inside the routes/index.js
app.get('/users', user.list); // calls the "list" function inside the routes/user.js file
Hope this helps.
Quick tip: app.use() is used to create middleware, which is a function that will get called on each request in your application, giving you, the developer, access to the request object req, and the response object res, and the power to change, or enhance your application somehow. The ability to "act in the middle of a request" is a powerful feature, and the reason why it was working for you in your original example is because your app.use() middleware was getting called when the request for / was being called, even though your app couldn't find /, which was lost when you re-declared the routes variable, you were still making a request to /, which your app.use() was able to see (because middleware gets called on EVERY request, even the "bad" ones), so your middleware was still seeing the [invalid] request to / and acting like this:
// This middleware will get called on every request,
// even on the invalid request for '/'
app.use( function(req, res, next) {
// this line of code will see that the
// request is for "/" and fire
if (req.url == '/') {
// the page now appears to render, because you are forcing the
// res.render code inside of your middleware, which isn't always
// recommended, but it is working for you in this example
// because its the only place in your example that can do anything
// when the '/' request is made
res.render('index', { title: 'Express!' })
} else {
// this is common middleware design pattern, the next()
// function tells the express framework to "move on to the next function"
// in the middleware stack
next();
}
});