HTML and CSS Reference
The guid Subelement
Each RSS item might have a string that uniquely identifies it, called the globally unique identifier . The guid
subelement has no specific syntax rules, but its content is usually a URL (Listing 8-21).
Listing 8-21. A guid Specifying a Permalink Related to the News Entry
<title>New HTML5 and CSS3 Tutorials</title>
<pubDate>Mon, 06 Feb 2012 14:22:00 +0930</pubDate>
<dc:creator>Dr. Leslie Sikos</dc:creator>
<description>Tutorials on HTML5 video embedding and CSS3 transitions</description>
<content:encoded>Several tutorials have recently been published on emerging
technologies such as HTML5 video embedding and CSS3 transitions.</content:encoded>
The guid subelement has an optional attribute, isPermaLink , that can be set to true or false . In the first case
(which is the default), the attribute value must be a URL that points to the full article or story described by the item
element). The false value is rarely used. In fact, the whole isPermaLink attribute is often omitted.
■ the guid subelements, if provided, should be unique throughout the rSS file. this criterion might be difficult
to meet if the frequent updates of the same web site are described multiple times in the file.
The value of a guid subelement is considered a string by RSS readers.
■ although the guid subelement is optional, it is recommended to provide it for all item elements in order to
The link Subelement
The URL of an item can be provided by the link subelement. Listing 8-22 shows an example.
Listing 8-22. A Link Declared for an RSS Item
The source Subelement
If the item content comes from an external RSS channel, it can be provided by the source subelement. The value is the title
of the resource channel. The source element has one required attribute, url , which is the URL of the resource (Listing 8-23).
Listing 8-23. The Source of an RSS Item
<source url="http://www.example.com/news.xml">John Smith Headlines</source>