The Anatomy of an RSS Feed

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The Anatomy of an RSS Feed
By Kris Hadlock
January 22, 2008

RSS has become the standard data format for communicating news, updates or any other type of information that a company or individual wants to syndicate to a large audience. The name is an acronym that stands for Really Simple Syndication, which is an XML format that consists of designated elements that are consistent for all RSS feeds and conform to the XML 1.0 specification. These elements need to stay consistent to allow for a standardized data format that RSS aggregators can then consume. In this article we'll take a look at the elements in this structure.

An RSS feed always starts with an <RSS> element, which contains an attribute called version, which specifies the version of the RSS feed. Here we focus on the RSS 2.0 format because it's the most commonly used today.

<rss version="2.0"> </rss>

The child of the <rss> element is the <channel>. This element is the containing element for the important data or content within the feed.

<rss version="2.0"> <channel> </channel> </rss>

In order to describe an RSS feed there are some tags that can be added to the beginning of a feed. The required <channel> elements are <title>, <link> and <description>. Optional channel elements are <language>, <copyright>, <managingEditor>, <webmaster>, <pubDate>, <lastBuildDate>, <category>, <generator>, <docs>, <cloud>, <ttl>, <image>, <rating>, <textInput>, <skipHours> and <skipDays>.

<rss version="2.0"> <channel> <item> <guid isPermaLink="false"> http://www.blogger.com/feeds/12931054/posts/full/115714541264251287 </guid> <pubDate>Fri, 01 Sep 2006 21:08:00 +0000</pubDate> <title>Secure Ajax Requests</title> <description> <div xmlns="http://www.w3.org/1999/xhtml">My latest article for InformIT, titled <a href="http://www.informit.com">How to Secure Ajax Requests</a> is on the homepage this week. This article focuses on ensuring that your database-enabled Ajax requests are secure and not leaving your database open for an attack. Enjoy...</div> </description> <link> http://www.krishadlock.com/blog/2006/09/secure-ajax-requests.html </link> <author>Kris Hadlock</author> </item> </channel> </rss>

This feed structure is standard for a weblog, as it consists of the most commonly used elements. By taking a look at this structure you can see that it's abstract, which is why it can contain any form of information. Even though the structure is abstract you can tell by looking at the feed elements that the data is straightforward. Each item element can contain the following sub-elements in order to describe the item in detail:

17. guid – The guid is an element that contains a string that uniquely identifies the item.

18. pubDate – The pubDate is the date that the item was published.

19. title – The title is the title that is specified for the item; in this case it's the title of the weblog post.

20. description – Contains the main data for the item, this element is used for the body of the weblog post in this case.

21. link – Contains a full URL to the individual page in which the specific item exists in detail.

22. author – Represents the author of the content that is presented within this item group.

23. category – Allows the item to be included into one ore more category.

24. comments - URL of page that contains comments related to the item.

25. enclosure – Can be used to describe a media object if one is attached to the item.
26. source – The RSS channel that the item came from.

Conclusion

RSS is a format that's become the standard for syndicating information as data. This allows developers to rely on the structure of the files to create programs that can read or parse the data into a readable format.

About the Author

Kris Hadlock has been a contract Web developer and designer since 1996. He is the author of Ajax for Web Application Developers and has been a feature writer for numerous Web sites and design magazines. To learn more about Kris, visit his Web site at www.krishadlock.com

This article originally appeared on WebReference.com