1 / 13

RESTfulness and AJAX

RESTfulness and AJAX. CS 4720 – Web & Mobile Systems. A Bright New Day with AJAX. Rich, responsive interfaces! Interactive pages! Fewer (if any) page refreshes! Able to withstand server issues!. AJAX: Official Definition.

hollie
Télécharger la présentation

RESTfulness and AJAX

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. RESTfulness and AJAX CS 4720 – Web & Mobile Systems

  2. A Bright New Day with AJAX • Rich, responsive interfaces! • Interactive pages! • Fewer (if any) page refreshes! • Able to withstand server issues! 2

  3. AJAX: Official Definition • From Ajax: A New Approach to Web Applications by Jesse James Garrett • Standards-based presentation with XHTML and CSS • Dynamic display and interaction with DOM • Data exchange and manipulation with XML • Asynchronous data retrieval with XMLHttpRequest • JavaScript holding it all together 3

  4. How does it work? • Relies on two main principles: • 1. Ability to modify the current page and have the changes show • 2. Ability to send/receive requests without blocking the thread 4

  5. Dynamic Display • The DOM: Document Object Model • In 1997, support for Dynamic HTML (DHTML) was added to major browsers • Allowed for the dynamic changing and redisplaying of the HTML element hierarchy • CSS (cascading style sheets) are a form of this too • Javascript can see the DOM and alter it on-the-fly 5

  6. How do we not block? • Javascript is the main reason we can do this. • Javascript has no support for threads at all! It’s completely event driven. Events like: • A button press • A mouse over • A click • Or, most importantly, an HTTP request 6

  7. XMLHttpRequest • An XMLHttpRequest encapsulates an HTTP request. • XMLHttpRequest support asynchronous invocation. • In other words, it just adds itself to the list of operations, but doesn’t lock resources. • Thus, the main thread is not blocked by the call, and the UI (or other system operations) can keep running in concert. 7

  8. XMLHttpRequest 8

  9. So… what do we send? • The name AJAX (Asynchronous Javascript and XML) would suggest that XML would be sent • But really, all you are doing is changing the DOM… so it could be anything • HTML (which is, of course, a form of XML) • Plain text (but that’s kinda boring) • Another formatted protocol (like SOAP) • Maybe even more Javascript 9

  10. Here comes a pattern… • How does this jive with the observer pattern? • Who is observing? Who is publishing? 10

  11. Example Code 11

  12. Available Toolkits • You don’t still use normal arrays in Java do you? So why do that with AJAX? • Prototype • Script.aculo.us • Dojo • DWR • Moo.fx • jQuery • Etc. 12

  13. Thanks • Many thanks to Ken Anderson @ Colorodo for some of this information • Some info also from the fine folks at Wikipedia • This slide deck brought to you by the letter “M” and the number “blue.” 13

More Related