About validation

Unlike other parsers, NRss will try to make sure that the read XML file is a valid RSS feed conforming to the declared version number. This means that:

• the elements and attributes required by the specification must be present in the feed.
• the feed must not contain elements not mentioned in the specification (unknown elements).
• the dates must conform to RFC 822, with the only difference that the year can be expressed as a four-digit number.

Unknown elements are those elements that are not in a namespace and are not specified by the RSS specification according to the version number declared in the <rss> element. Unknown elements in a namespace are of course ignored. NRss will throw an exception if the feed does not follow the rules mentioned above.

For example, items of a version 0.91 feed cannot contain a <pubDate> element. NRss will throw an exception if it meets such and element. Another example could be a <foobar> element, which will also cause an exception to be thrown.

However, there may be cases when you want to read a RSS feed even when you know it is not valid. The parser can take options that specify that missing and unknown elements are to be ignored. Be warned, however, that support for reading such damaged feeds is limited. For information about these options, see the RssReaderOptions enumeration in the documentation.