1. AJAX Chat Analysis and Design Rui Zhao CS5260 2012SPG UCCS

2. What is AJAX Chat? A free and fully customizable open source web chat software implemented in JavaScript, PHP and MySQL [1] – Flash – Ruby Chat integrates nicely with phpBB, MyBB, PunBB, SMF, vBulletin and other PHP community software. Rui Zhao All Rights Reserved 2012

3. What did I do? Analyze the chat system, and both server and client will be elaborated in four aspects (table design, infrastructure, collaboration and interface). Discuss new features and how to add them to the system. Propose problems, especially those in design and codes, accompanied with suggestions about how to solve them. Rui Zhao All Rights Reserved 2012

4. System Requirements Running Environments – Server-Side PHP >= 4 MySQL >= 4 Ruby >= 1.8 (optional) – Client-Side Enabled JavaScript Enabled Cookies Flash Plugin >= 9 (optional) Rui Zhao All Rights Reserved 2012

5. System Requirements Developing Environments – Zend Studio for Java and Php script development on both client and server; – FLEX for client flash development; – MySQL for server database development; – Ruby for server socket development. Rui Zhao All Rights Reserved 2012

6. Features Main Feature Detail Private messaging - Multiple/Private channels - Ignore/Ban and revoke users - List online/ignored/banned users - Change username - Private channels - Custom setting Such as BB Code, hyperlinks, line breaks. Possibility to delete messages inside the chat - Developed with Security as integral part - Blink window title on new messages - Show each user’s IP - Rui Zhao All Rights Reserved 2012

7. Techniques AJAX – AJAX (Asynchronous JavaScript and XML) is a technique for creating fast and dynamic web pages. [3] – AJAX uses combinations of XMLHttpRequest object (to exchange data asynchronously with a server); JavaScript/DOM (to display/interact with the information); CSS (to style the data); XML (often used as the format for transferring data). Rui Zhao All Rights Reserved 2012

8. Techniques FLEX – Like Flash, Flex creates SWF files that are rendered by Flash Player. [4] – However, Flex is primarily a developer's tool – The way you develop Flex applications is entirely different than the way you develop Flash RIAs. All Flex development is based upon a framework that provides you with reusable and extendable UI components, data retrieval services, event handling functionality and much more. Rui Zhao All Rights Reserved 2012

9. Techniques FABridge – A new JavaScript library enables developers to easily integrate Flex applications with Ajax or DHTML code running in the browser. [5] – Is built with the “don’t repeat yourself” principle in mind. – With FABridge you can make your ActionScript classes available to JavaScript without any additional coding Rui Zhao All Rights Reserved 2012

10. Client Infrastructure Module Detail FABridge Translate XML stream to ordinary message and update flash on website: 1.JSP receives and parses XML message (AJAX); 2.JSP calls methods in ASP to updates flash on web page (FLEX). JSP Responsible for performing user’s actions on web page: 1.Receive and parse input actions and parameters, such as client setting, kicking some one and chat message; 2.Organize standard HTTP GET/POST messages; 3.Send messages to server. Rui Zhao All Rights Reserved 2012

11. Server Infrastructure Module Detail Socket Listen HTTP requests and decode them to XML stream: 1.Server.conf defines parameters of socket, such as port and IP; 2.Server.rb starts socket and port listener, receives and parses XML stream. Application Parse request and write useful data to database, then organize response to request. 1.Config.php defines template for request variables; 2.Templates are used to generate standard XML/XHTML stream when organizing response; 3.Database connector writes data to database and query data from database. Php Platform Send response. Rui Zhao All Rights Reserved 2012

12. Suggestions Some files’ length is more than 3000 lines, and it will surely decrease the readability and destroy the structure of codes; Inadequate code comments, the best ratio of comments to codes is between 1:1 and 2:1; In php coding, it is better to use $_Get and $_Post instead of $_Request. In ordinary, $_Request could stands for $_Get. And when $_Get is null, $_Request will refer to $_Post. However, when both $_Get and $_Post exist, who does $_Request refer to? And how to get $_Post by using $_Request now? Therefore, $_Request is a dangerous variable and is not recommended in php coding; Rui Zhao All Rights Reserved 2012

13. Suggestions New features suggested: – Banned time. The system bans a user only for five minutes, and it is not possible to choose a start time and end time for banning; – No registration entry. The system does not provide an entry to create new users, and there is no table for saving user information. Of course if the chat system is combined with a forum, this will not be the problem. If registration is not allowed for some reasons, the table for user management is still in need. – Fusion between authority management and role management. The system does not connect each role with an authority by an interface, but by simply putting authority management into role management; – Whether actions of log in or log out should be recorded into user on-line table or another new table permanently will be further discussed. Since our purpose is to make the chat system a forensic one, maybe any action on-line should be recorded without any exception; – It is better to retrieve environment information of OS from each client, and we could consider it an evidence of chatting actions. Because probably it is impossible to know who is actually using a specific user name. One of the important information is user name logged on OS. Rui Zhao All Rights Reserved 2012

14. Reference [1] https://blueimp.net/ajax/ [2] http://sourceforge.net/apps/mediawiki/ajax- chat/index.php?title=Main_Page [3] http://www.w3schools.com/Ajax/ajax_intro.asp [4] http://learn.adobe.com/wiki/display/Flex/Get+oriented+to+Flex [5] http://tv.sys-con.com/node/193201 Rui Zhao All Rights Reserved 2012