Node.js
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This document discusses developing for Node.js and includes an agenda covering creating an HTTP server, understanding the event loop and callbacks, creating echo and file upload servers, adding routers using Crossroads, and building a REST API with Express. It also introduces the presenter, Dhananjay Kumar, and provides overviews of Node.js as an asynchronous event-driven JavaScript runtime and how Node works using a single thread and non-blocking I/O. Code demos are included for core Node.js concepts.
Node.js
- 2. Agenda What is this buzz Node Create first HTTP Server : Demo How Node works ? Understanding EventLoop and Callback Create Echo Server : Demo Create app to upload large file asynchronously : Demo Create routers using Crossroads : Demo Create REST API using Express and Visual Studio : Demo
- 3. Your Presenter Dhananjay Kumar – Evangelist , Telerik – Microsoft MVP – Mentror C-Sharpcorner – @debug_mode – http://debugmode.net – http://telerikhelper.net – [email protected]
- 4. What is Node.js ? Asynchronous Event Driven Server Side JavaScript Runs on Google JS V8 Engine Non-blocking I/O and File API Highly Scalable Single Threaded Node Apps are created using JavaScript Faster in performance
- 5. Demo : Create first web Server
- 6. Let us understand code line by line Line 1 Line 4 • • • • • Loading http module It is required to work with HTTP request and response It is required to create HTTP Server Line 2 • • • • Create server using createServer() function It takes a callback as parameter . It takes HTTP request and response as paramtere Callback got two input parameter . Both input parameters are readable and writeable stream • Writing response header It takes a JSON object as optional second parameter second parameter contains informations like • • • • Content Length Content Type Connection Accept Type
- 7. Let us understand code line by line Line 9 Line 5-6 • • • Writing data in response Data can be written in form of string or buffer ServerResponse.end indicates the communication has been finished • • • Line 10 • Printing a message createServer() method is finished with chained http.Server.listen() method It specifies port number on which request will be listen Optional host name
- 8. How Node works ? • It works on single thread • It handles all request asynchronously on same thread • It does not create new thread for each request which is very unlikely like other web servers • It does not wait to complete a request Keep poling for event in EventLoop When gets event process asynchronously and assign a CallBack CallBack get executed once event execution is complete
- 9. Visual Studio and Node Manage NPM Modules
- 10. Events in Node • Each objects in Node emit an asynchronous event. • event is handled by an object EventEmitter. • EventEmitter is underneath every object.
- 11. Streams in Node Demo on echo server Demo on uploading file asynchronously
- 12. Routers in Node Modules to create Routers Demo add routes using Crossroads • • • • • Express Director Bouncy Backbone Crossroads
- 13. Demo : REST API on Node.js • • • • • Export data from a Module Add routes in Express Map routes to function Test in fiddler Use Visual Studio Template
- 14. Demo : REST API on Node.js Step 1 : Create JSON Object Array
- 15. Demo : REST API on Node.js Step 2 : Retrieve function
- 16. Demo : REST API on Node.js Step 3 : Add function
- 17. Demo : REST API on Node.js Step 4 : Update function
- 18. Demo : REST API on Node.js Step 5 : Delete function
- 19. Demo : REST API on Node.js Step 5 : Add Routes