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SWFAddress - Deep Linking for Flash

A new open source project

SWFAddress is a new open source project that provides deep linking and search engine indexing for Flash Websites and applications. In other words, it enables the Back, Forward, and Reload buttons of the browser and creates unique URLs that can be sent over e-mail or IM. Recently it reached version 1.0 and quickly gained the attention of top design agencies and interactive developers. SWFAddress started as a small experiment that aimed to enhance a typical Flash Website by presenting the portfolio of a fellow photographer. It adopted all the best practices available on the Internet and became one of the best solutions among the growing number of similar libraries. After a successful release candidate, SWFAddress went beyond history management and bookmarking by providing an innovative approach for dealing with search engines. SWFAddress's way to success is based on simplicity, a rich feature set, and quality. SWFAddress is the third free software project of Asual DZZD, a small company from Sofia, Bulgaria. Previously known for its user interface framework, EnFlash, and ActionScript preprocessor, EnLarge, Asual continues to provide new ideas and solutions that target the Adobe Flash Player Platform. All the company's projects rely on the hosting services of Sourceforge.net and take part in the growing community of OSFlash.org. SWFAddress is released under the terms of the open source MIT license.

Technical facts about the project include:

  • SWPAddress is a combination of the JavaScript and ActionScript classes that communicate via the ExternalInterface introduced in Flash 8.
  • Provides three different ActionScript classes for each version of the language.
  • Supports Flash Player 8+ and all the major browsers including Mozilla Firefox, Internet Explorer, Safari, and Opera.
  • Uses mod_rewrite with PHP and UrlRewrite with JSP to provide SEO support for Google, MSN, Yahoo and Ask.
  • Comes with sample scenarios for Flash, Flex and MTASC.
SWFAddress was the first add-on for the fantastic SWFObject script by Geoff Stearns. Seamless integration with such a popular Flash embedding solution was one of the key values that attracted the developer community. The increased request for SWFAddress will probably lead to support for alternative methods such as the default Flex 2 templates or custom-made Flash writing scripts. SWFAddress can be quickly added to a Website that uses SWFObject only by inserting the JavaScript file like this:

<script type="text/javascript" src="swfobject/swfobject.js"></script>
<script type="text/javascript" src="swfaddress/swfaddress.js"></script>

The internal implementation of SWFAddress is simple and straightforward. Once a Flash movie containing the library is embedded in an HTML page, it automatically initializes itself and provides the developer with notification of state changes that need to be implemented. This might not be the easiest task for everybody, but SWFAddress streamlines the process by fully supporting testing workflow inside the Flash Program and Standalone Player. URL changes can be invoked from mouse-click events, frame actions, or HTML links.

Here is sample code that can be added to a MovieClip button:

this.onRelease = function () {

      SWFAddress.setValue("/portfolio");
}

For links in HTML-formatted TextFields, the following approach should be used:

<a href="asfunction:SWFAddress.setValue,/portfolio/">Go to Portfolio</a>

SWFAddress has a single onChange event where the navigation logic needs to be coded. The complexity may vary depending on the Website, but if it's planned from the beginning, it may improve maintainability by centralizing all the controller actions. A simple navigation handling can look like this:

SWFAddress.onChange = function () {

      var navigation = new Object();
      navigation.home = {frame: 1, title: "Welcome"};
      navigation.about = {frame: 10, title: "About Us"};
      navigation.contact = {frame: 20, title: "Contact Us"};

      var value = SWFAddress.getValue();

      website_mc.gotoAndStop(navigation[value].frame);

      SWFAddress.setTitle(navigation[value].title);
}

The setTitle method allows you to add unique titles to every section of the Website and they will appear in the browser's titlebar. It should be used inside the onChange event in order to correctly display the initial title value when the page loads.

The SEO support of SWFAddress is probably the most unique feature of the project. It enables the generation of real links that expose the appropriate content to search engines. The magic happens with some interesting URL rewriting and some trivial server-side code. The following is an example how it works for a Website located at http://www.domain.com that contains a portfolio section.

SWFAddress uses http://www.domain.com/#/portfolio/. The URL that can get indexed is http://www.domain.com/portfolio/ and therefore it should exist as a link in the HTML code of the page. When someone visits the indexed address, the rewriting functionality makes a redirect to the URL that SWFAddress expects. Everything happens transparently for the end user and further navigation through the Website correctly changes the Address bar value. The situation is different when the same link is followed by a search engine bot. In this case the address is rewritten without any redirection to http://www.domain.com/?swfaddress=/portfolio/. The page that handles all this should use a server-side technology in order to generate the appropriate content depending on the "swfaddress" parameter value.

Requests containing GET parameters such as http://www.domain.com/#/portfolio/?desc=true&year=2001 are handled similarly. The search engines will index http://www.domain.com/portfolio/?desc=true&year=2001 and the script will expect http://www.domain.com/?swfaddress=/portfolio/&desc=true&year=2001.

The result is a fully indexed Flash Website with deep linking support.

The following sample queries showcase how the SEO sample hosted at Asual.com is indexed:

http://www.google.com/search?q=site:asual.com+aliquet
http://search.yahoo.com/search?p=site:asual.com+praesent
http://search.msn.com/results.aspx?q=site:asual.com+torquent

While this approach improves the usability of Flash content over the Web, it also requires an additional effort, such as some manual work for static Websites and some smart code for dynamic ones. The best case will be a Flash CMS that automates the whole process.

Something similar has still not been created for AJAX-heavy Websites, although a part of it is documented in the Unique URLs pattern on AjaxPatterns.org. It will be great for both Flash and AJAX if a technique like this gets adopted and improved over time.

SWFAddress promises to continue adding interesting functionality like AJAX support, transparent user tracking with Google Analytics, and enhanced event handling. It should definitely be considered for your next Flash project.

More Stories By Rostislav Hristov

Rostislav Hristov works for Asual Interactive Systems. Based in Sofia, Bulgaria, Asual provides outsourcing services to clients all over the world.

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