Downloaded 31 times
Uploaded byAhmed Assaf
Module design pattern i.e. express js
This document discusses Express.js, a popular Node.js web application framework. It begins by explaining that Express makes developing websites, web apps, and APIs easier by providing route support and templating engine integration. It then demonstrates how to install Express and a templating engine like Jade. Several code examples are provided, including creating a simple REST API with routes, using Express to serve multiple pages with query parameters, and building a RESTful API for a resource like dogs. Resources for further learning about Express and Node.js are listed at the end.
More Related Content
Similar to Module design pattern i.e. express js
Module design pattern i.e. express js
- 1. 02 |Understanding Module Design Pattern 03 | Express.js Ahmed Assaf | Senior Software Engineer
- 2. Setting Expectations TargetAudience Web Developers Web Designers Developers with experience using other service side languages such as PHP, ASP.NET, Python, Ruby etc.
- 3. Module Overview Exportsa Namespace Exports a Function Exports a Higher Order Function Exports a Constructor Exports a Singleton Extends a Global Object Applies a Monkey Patch
- 4. Module Design Patterns Modules are still JavaScript Possess many of the challenges of pre-ES6 Javascript Design Patterns to help with Encapsulation Stable Interface
- 5.
- 6. Exports a Namespace Module returns an object Object contains properties and functions Calling code can refer to properties and execute functions
- 7. Simply return anobject with whatever properties and functions the calling code should have access to //private module stuff can happen here //then return an object module.exports = { property1: 'value', property2: 'value', function1: function(){ … } function2: function(){ … } }
- 8. Core 'fs' Nodemodule returns an object readFile and ReadStream are functions of the returned object Both are accessible from this calling function Analogous to static classes and members in other languages var fs = require('fs'); fs.readFile('./file.txt', function(err, data) { console.log("readFile contents: '%s'", data); }); new fs.ReadStream('./file.txt').on('data', function(data) { console.log("ReadStream contents: '%s'", data); });
- 9.
- 10. Exports a Function Factory function Gives you instancing since all variables are encased in a closure Closure is run for each require() Revealing Module Pattern you may have used in client side JavaScript ProTip If you don’t need instancing – export a namespace If you need instancing – export a constructor
- 11. module.exports = function(options){ options = options || {}; var loggingLevel = options.loggingLevel || 1; function logMessage(logLevel, message) { if(logLevel <= loggingLevel) { console.log(message); } } return { log: logMessage }; }
- 12.
- 13. Exports a HigherOrder Function
- 14. Exports a HigherOrder Function Like the former, but also receives a function that affects the behavior of the function it returns Express middleware is a great example - functions are provided and the middleware function is returned
- 15. Chaining is possiblewith the app object because the middleware functions each return it. var app = require('express')(); app.use('/route1', function(res, req, next) { //do something next(); }); app.use('/route2', function(res, req, next) { //do something next(); });
- 16.
- 17. Exports a Constructor Constructor function creates instance Prototype used to define behavior Caller creates instance with new keyword Multi instance
- 18.
- 19.
- 20. Exports a Singleton Instantiates object before returning it Causes all calling modules to share a single object instance
- 21. When an objectis instantiated before it's returned, it acts as a singleton. function Something() { … } module.exports = new Something();
- 22. Mongoose is oneexample of a good use of the singleton pattern var mongoose = require('mongoose'); mongoose.connect('mongodb://localhost/test'); var Cat = mongoose.model('Cat', { name: String }); var kitty = new Cat({ name: 'Zildjian' }); kitty.save(function (err) { if (err) // ... console.log('meow'); });
- 23. Extends a GlobalObject
- 24. Extends a GlobalObject Modifies an existing type i.e. String Doesn’t have to export anything Makes for nice calling syntax but can be difficult to track down source in large project Frowned upon in open source packages
- 25. Applies a MonkeyPatch
- 26. Applies a MonkeyPatch A monkey patch is the dynamic modification of a class or object at runtime to fix a bug in existing code Similar to previous pattern (extends a global object) but affects cached node modules
- 27. The winston loggerdefaults all profiling statements to the info level and you can’t change A quick monkey patch allows you to log data out as any log level you want and replace the built in functionality without forking the code base winston.Logger.prototype.profile = function(id) { // Altered behvaior or winston loggers profile function };
- 28. Summary Exports aNamespace Exports a Function Exports a Higher Order Function Exports a Constructor Exports a Singleton Extends a Global Object Applies a Monkey Patch
- 29. 03 |Express.js
- 30. What is Express? Express is a minimal, open source and flexible node.js web app framework designed to make developing websites, web apps and APIs much easier.
- 31. Why use Express? Express helps you respond to requests with route support so that you may write responses to specific URLs. Supports multiple templating engines to simplify generating HTML.
- 32. Installing and UsingExpress
- 33. Installing and UsingExpress npm install express npm install jade
- 34. Creating a SimpleREST API
- 35. Explanation of Routes A router maps HTTP requests to a callback. HTTP requests can be sent as GET/POST/PUT/DELETE, etc. URLs describe the location targeted. Node helps you map a HTTP GET request like: http://localhost:8888/index To a request handler (callback) app.get('/index', function (req, res) {});
- 36. Creating a SimpleExpress Application var express = require('express'); var app = express(); app.get('/', function (req, res) { res.json({message:'hooray! welcome to our api!'}); }); app.listen(process.env.PORT || 8080);
- 37. DEMO Creating a simpleREST API with Express Framework
- 38. DEMO Using the express-generatorpackage.
- 39. DEMO Using Express forMultiple Pages with Query Parameters
- 40. Building a RESTfulAPI for Dogs Resource GET PUT POST DELETE Collection URI, such as http://api.example .com/v1/dogs/ List all the dogs Replace all the dogs with a new collection of dogs. Create a new dog in the collection. Delete the entire dog collection. Element URI, such as http://api.example .com/v1/dog/1 Get a specifi c dog. Replace a dog in the collection with another dog. Not used. Delete the dog from the collection.
- 41. DEMO Using Express tobuild a RESTful API
- 42. Resources Express Frameworkhttp://expressjs.com/ Intro to Express http://code.tutsplus.com/tutorials/introduction-to-express-- net-33367 Jade Templates http://jade-lang.com/tutorial/ JavaScript and Jade Templating http://www.slideshare.net/wearefractal/jade-javascript-templating
- 43. Resources Using Node.jswith Visual Studio Code #MVA Course By Stacey Mulcahy | Senior Technical Evangelist Rami Sayar | Technical Evangelist Mastering Node.js Modules #MVA Course By Chris Kinsman | Chief Architect at PushSpring https://blog.jcoglan.com/2013/03/30/callbacks-are-imperative-promises-are-functional- nodes-biggest-missed-opportunity/ http://code.tutsplus.com/tutorials/using-nodes-event-module--net-35941 http://spin.atomicobject.com/2012/03/14/nodejs-and-asynchronous-programming-with- promises/ Github repo: https://github.com/AhmedAssaf/NodeMVA From : https://github.com/sayar/NodeMVA
Editor's Notes
- #2 1
- #4 After this slide, it’s all demo. See the demo script for the majority of the content
- #6 ~7 min
- #10 ~7 min
- #14 ~7 min
- #17 ~7 min
- #20 ~7 min
- #24 ~7 min
- #26 ~7 min
- #29 After this slide, it’s all demo. See the demo script for the majority of the content
- #30 29
- #33 32
- #35 34
- #39 npm install -g express-generator express /tmp/foo