Today everyone talks about Web 2.0. But while the idea of a collective intelligence, implied here by the term's inventor Tim O'Reily remains an object of trivial speculations, it is obvious that the World Wide Web is changing. Web applications are increasingly approaching the level of functionality, which is usually found only in desktop applications. And as this trend is gaining momentum, we can already witness the dawn of a new era brought about by a novel kind of web applications - Rich Internet Applications (IRA). At the same time, the popularity of terms like Web 2.0 and RIA makes developers use them as an attractive label on their products, without actually understanding the meaning behind those notions. So what does RIA mean, eventually?
The term Rich Internet Applications (RIA) was first mentioned in Macromedia's promotional materials in March 2002. By this the company's managers wanted to point out that the well-known Flash technology is not limited to creating attractive visual web-elements, but can also be used to develop fully functional web-based business applications. Apart from providing user with data, static pages of older-type sites are much less flexible in terms of user-data interaction compared to desktop applications. Every time you request additional data (navigate the site) or upload data to server the pages have to reload. This is often inconvenient and, above all, can compromise security because of the possibility of data loss (say, due to a lost server connection). Yet this is exactly the way Web 1.0 works. Every time you type URL or save data in a web form, server receives instructions which it then uses to form a page you see next. With RIA, there's no need to reload pages. As you click to receive additional data or send data to server, the latter receives corresponding instructions and uploads the results onto the page. The application receives server's response and changes accordingly. For example, if you browse an internet catalogue of an older type, every time you hit the button "next 20 items" you will have to wait for the page to reload and for a new page to shape. With a RIA-based site, you can request items 50 to 80 or all items in a specified price range on the same page, and with every new query only the list of items will be updated.
Today RIA can be developed with the help of AJAX, Adobe Flex, Windows Presentation Foundation, Flash, Java-applets, Java and some declarative languages - such as XUL and MXML. Of all these tools only AJAX and Flash gained wide popularity - mainly because they are easily available. And whereas development of Flash-based applications is quite a resource-consuming and expensive process, developing RIA with AJAX takes hardly more time then it would with an older-type, classical web-site. In most current projects Flash is only used when it is needed.
The very name - AJAX (Asynchronous JavaScript and XML) - reveals the essence of the technology. It allows the client engine and the server-based part of the web-application interact asynchronously. This means that your browser can request server at any point (say, when you hover your mouse over a link) and, vice versa, server can upload data to browser at any time, without waiting for a new page to be requested. How does it actually work?
One of the most popular uses that AJAX has found is in the web-based drag & drop technology. You must have already seen the virtual desktop services - such as found at www.netvibes.com and www.pageflakes.com. Their users can arrange widgets (useful data from other servers) on the screen and adjust their size just like we usually do it in Microsoft Windows. These features are now increasingly found in business-applications. For example, at www.atlas.cz users can customize the starting page with as much ease as any virtual desktop.
The possibility to customize pages with the help of ready-made design templates reduced the dependence of CMS (Content Management Systems) users on site developers. Using the mouse a CMS administrator can arrange various data modules, specify their size, color and other attributes at a page. Then s/he can save the current configuration which will later be displayed to site users. Yet advantages provided by Drag&Drop technology to CMS administrators are even greater when it comes to site content management. In latest CMSs all the administrator has to do to change position of any document in the structure (or of an entry in the list) is to drag and drop it at the desirable point. It is exactly the way files are managed in Microsoft Window Explorer.
As we've already mentioned, with RIA there's no need to upload all the user data at once. Parts of it can be uploaded later, when they are actually requested for. For example, when administrator switches to the CMS's site structure management interface, only the basic level of the hierarchy tree is loaded. If later user wants to explore any of the tree's "branches", the additional data will be uploaded instantly. This feature is even more important in managing various lists. The application returns to the interface only those entries that user specifically requested. Moreover, even data input procedures acquire new features. Modern web-applications increasingly offer input option which acquired wide popularity thanks to Google Suggest service. As soon as you start to type something in the required field, a dropdown list appears with suggestions based on the already typed in elements. Those who at least once had to, say, choose a producer from a seemingly endless dropdown list in the SELECT field will fully appreciate the convenience of this feature.
The fact that there's no need to reload the page every time its user performs an operation changes the very perception of a web-interface. You can type in data in several forms placed on one and the same page but, say, on different tabs. Then all the data can be saved simultaneously. And, importantly, in case due to some reason (a lost connection, an internal error etc) the data is not saved, the interface will report it and let you try again. And we all know only too well that poor security was one of the basic flaws with older-type web interfaces.
It is obvious that apart from everything else IRA-based sites can report the status of processes and their results. Today it is only perceived as natural when any element involved in some system operations displays their status on a special bar. Let's say, for example, that you requested a list of specified items to be displayed by an e-catalogue. In that case you have the right to know what the system is up to from the moment of query to the moment the list is displayed. If due to some reason the server is unable to return the requested data, you should receive the corresponding message.
With RIA the functionality and security of CMSs reach a totally new level, which earlier was available only with desktop applications. Yet we should not forget that RIA-based interfaces are capable of interacting not only with their own server software, but with third-party applications as well. This fact lets us hope that present-day CMSs will gradually evolve towards ECM (Enterprise Content Management), thus bridging the gap between corporate sites and corporate network information resources.
This article features examples of Site Sapiens 3.0 CMS interfaces (www.sitesapiens.com)
