This document provides an overview of creating a web application using Node.js with the Express framework, including setup instructions, routing, middlewares, and configuration for different environments. It highlights the use of Express for handling requests and managing sessions, as well as rendering views with template engines. The document outlines essential functions and structures for building a basic Express application.

1. Node.js with Express
web application framework for node
Gergely Nemeth

2. What is Express?
get '/' do
redirect to('/hello/World' )
end
get '/hello/:name' do
"Hello #{params[:name]}!"
end
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● Node.js web framework
● Sinatra-inspired

3. Getting started
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● npm install express
var express = require('express');
var app = express();
app.get('/hello', function(req, res){
res.send('Hello World');
});
app.listen(3000);
console.log('Listening on port 3000');

4. Getting started #2
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● npm install -g express
● express --sessions --css stylus --ejs myapp
● create : myapp
create : myapp/package.json
create : myapp/app.js
create : myapp/public
create : myapp/public/javascripts
create : myapp/public/images
create : myapp/public/stylesheets
create : myapp/public/stylesheets/style.styl
create : myapp/routes
create : myapp/routes/index.js
create : myapp/views
create : myapp/views/index.ejs

5. Configuration
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Used to separate production/development/etc...
configurations (based on NODE_ENV)
// all environments
app.configure(function(){
app.set('title', 'Rescue');
})
// development only
app.configure('development', function(){
app.set('mongoUrl', 'localhost/dev');
})
// production only
app.configure('production', function(){
app.set('mongoUrl', 'n.n.n.n/prod');
})

6. Middlewares
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● logging, auth, gzip, csrf protection, session
management, etc...
● called sequentially, next() callback can trigger the next
middleware
//built-in middlewares
app.use(express.logger());
app.use(express.compress());
app.use(express.methodOverride());
app.use(express.bodyParser());
//custom error handling
app.use(function onError(err, req, res, next) {
//do something with the error
next(err);
});

7. Routing
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app.VERB(path, [callback...], callback)
● GET, POST, PUT, DELETE, PATCH
● [callback...] are middlewares
app.get(/^/commits/(w+)(?:..(w+))?$/, function(req, res){
var from = req.params[0];
var to = req.params[1] || 'HEAD';
res.send('commit range ' + from + '..' + to);
});

8. Sessions
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● With middlewares
app.use(express.cookieParser()); app.
use(express.cookieParser('some
secret'));
● For authentication use:
○ Passportjs
○ Everyauth

9. Rendering
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● With template engines: Mustache(hogan), Jade,
EJS...
● Layout, views, partials
● Variables are passed to the render engine
app.get('/', function(req, res) {
res.locals = {
title: 'Title',
};
return res.render(
'index',
{
partials:
{
part: 'part',
}
}
);
});

10. Rendering #2
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● part.html
<h1>{{ title }}</h1>
● index.html
{{> part}}
Hello world!