Building Apps with Node.js and Express

A walkthrough for building simple server-side web apps with the Express framework for Node.js.

Transcript

1. Building Apps with
   Node.js and Express
   by Nicolas McCurdy
   

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2. “Node.js® is a platform built on Chrome's
   JavaScript runtime for easily building fast,
   scalable network applications.”
   - nodejs.org
   What is Node.js?
   

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3. What is Express?
   “Fast, unopinionated, minimalist web
   framework for Node.js”
   - expressjs.com
   

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4. What is Express?
   ● Express is a web framework built on top of Node.js.
   ● Inspired by the Sinatra web framework.
   ● Helps you create modular web applications.
   ● Based around the concept of middleware.
   

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5. Installing Node.js and Express
   ● Want to follow along? Get this presentation at sse.se.rit.
   edu/go/expresstalk.
   ● Install Node.js.
   Windows and Mac: Use the Installer from nodejs.org/download.
   Linux: Look for “node” in your package manager or build it from source.
   ● Install Express.
   Run npm install express in the directory where you want to put your
   app.
   

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6. Hello World
   1. Create app.js.
   var express = require('express'); // load the Express module
   var app = express(); // create a new Express app
   // Respond to requests for / with “Hello World!”.
   app.get('/', function (request, response) {
   response.send('Hello World!');
   });
   // Start a server with the Express app on port 3,000.
   var server = app.listen(3000, function () {
   console.log('Example app listening at http://localhost:3000/');
   });
   

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7. Hello World
   2. Run node app.js.
   3. Open http://localhost:3000 in your web
   browser.
   4. If you want to create a package.json for sharing your
   app and installing dependencies, run npm init.
   

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8. Middleware
   ● A function executed by the Express router after a
   request but before the final route.
   ● Middleware can be used for logging, error handling,
   template rendering, routing, etc.
   

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9. Using Middleware
   ● Express’s app.use() can be passed your own
   middleware function or a function from a middleware
   library to add it to all requests.
   ● In your middleware function, you must call next()
   when you’re done to let other middleware run (unless
   you want to end the middleware stack).
   ● Order matters!
   

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10. Time Logging with Middleware
    var express = require('express');
    var app = express();
    app.use(function (request, response, next) {
    console.log('Time: ' + new Date());
    next();
    });
    app.get('/', function (request, response) {
    response.send('Hello World!');
    });
    app.listen(3000);
    

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11. Express Generator
    The Express generator is a useful tool which creates a
    modular skeleton for new Express projects.
    

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12. Using the Express Generator
    1. Install the Express app generator
    a. npm install express-generator -g
    2. Use the generator to create a new app
    a. express --ejs example
    b. cd example
    c. npm install
    3. Edit your app however you’d like and run it with npm
    start.
    

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13. Directory Structure
    ● app.js
    ● package.json
    ● bin/
    ● node_modules/
    ● public/
    ● routes/
    ● views/
    

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14. Useful npm Commands
    ● npm install
    Installs all your dependencies.
    ● npm install --save
    Installs a specific package and saves it to your dependencies.
    ● npm start
    Runs your app.
    ● npm test
    Runs your tests (if you have a test script in package.json).
    

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15. FAQ
    ● What about models?
    Express doesn’t have models. You can set up model objects yourself or
    use a library.
    ● Is it production ready?
    Yes, it is used in production by many large organizations.
    ● What CSS preprocessors and templating engines
    are supported?
    The Express app generator supports several including ejs, jade, and less,
    but you can use pretty much anything that conforms to Express’s
    templating APIs.
    

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