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p>Although there are some varying opinions, the most common definition of RSS is that it stands for Really Simple Syndication. An RSS PODCast feed may be dynamically generated, but it appears to the subscriber (or consumer or user) of the feed as a file that is retrieved. Typically it is retrieved from a web server, but if you have an RSS feed file on your hard disk, you can open it. Or you could make your own and open it! An RSS feed, whether PODCast or other, is just a list of files. The files in the list usually contain audio, video, photos or other images. So, to summarize, an RSS feed is a file that contains a list of files. This list of files represents audio files, pictures, videos, images, or other data files. The files are sometimes referred to as episodes or programs if the feed is related to something delivered on a regular basis.
Make up your own? How does anybody ever agree on anything then? Well I'm glad you asked! XML also has the capability of checking the tags you have used in XML file against a list of allowed tags, called a schema. Interesting enough, this list of allowed tags is also in XML! This process is called validation and an XML parser or XML validator is used for this. There are web pages where you can validate RSS feeds. So if you make a schema (or XML file) of tags and enough people agree with you and start using it, you can exchange data in a common, easily verifiable format. That is exactly what RSS is. RSS is a schema for an XML file. The schema includes the tag names that were made up to hold the information such as the title and author of the RSS feed, and then there is a section for each file in the feed that has the name, title, location, length, description, date created, and author.
So what's all the fuss? And why does it seem to be so complicated? Well the list inside the file is in a special format or language called XML, or eXtensible Markup Language. Yes another TLA ... three letter acronym. XML provides rules for putting data in a file so that the parts of the file can be easily identified. You "markup" the data by surrounding the data elements in the file with special markers and software, called an XML parser, is able to locate and navigate through the data in an easy way (well easy for programmers). The "markers" are the < and > symbols surrounding an the name of an element. Sometimes this is referred to as a tag. There is a tag for beginning a data item and a tag for ending. So inside an XML file you might find a "title" that looks like this:
RSS newsreaders, RSS aggregators, iTunes, and many other programs can get an RSS feed and use the RSS schema to validate it, then retrieve the files in the list to your program to listen or view or whatever!
There are picky rules about making XML files and further rules regarding the RSS schema. But if you follow the rules you can use any old text editor to create an RSS Feed for your own files that you can use locally. If you want to make an RSS Feed available to web surfers over the Internet, you will have to make sure to put the RSS Feed file on a web server AND make sure the files referenced in your RSS Feed are available via a web server as well.
If you know how web pages work, then you know they use the HyperText Markup Language (HTML) and inside they also have tags like this. The ancestry of HTML and XML is much the same so this is not surprising. However, HTML has a fixed or defined set of tags, whereas XML lets you make up your own!
If you want to subscribe to an RSS PODCast Feed with iTunes or see the Technical Specification for RSS come on over to my website shown below.
As an alternative you can use a web page I created that will help you generate a valid RSS Feed that will display in your browser. Then you can view the source and copy it to use on your local disk or save and upload to web server.
Previous article: 29 December 2006
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