Cook Computing

Windows Vista RSS Platform and ttl, skipHours, skipDays

March 7, 2006 Written by Charles Cook

A snippet of information about the RSS platform in Windows Vista. I was interested to know if the platform will support the RSS features which allow a feed provider to reduce load on their feed (assuming consumers are obliging): ttl, skipHours, and skipDays. The RSS 2.0 spec describes these as:

<ttl> sub-element of <channel>

<ttl> is an optional sub-element of <channel>.

ttl stands for time to live. It's a number of minutes that indicates how long a channel can be cached before refreshing from the source. This makes it possible for RSS sources to be managed by a file-sharing network such as Gnutella.

Example: <ttl>60</ttl>


An XML element that contains up to 24 <hour> sub-elements whose value is a number between 0 and 23, representing a time in GMT, when aggregators, if they support the feature, may not read the channel on hours listed in the skipHours element.

The hour beginning at midnight is hour zero.


An XML element that contains up to seven <day> sub-elements whose value is Monday, Tuesday, Wednesday, Thursday, Friday, Saturday or Sunday. Aggregators may not read the channel during days listed in the skipDays element.

I posted a question in a comment on this entry in the RSS Team blog and Jane Kim replied:

The sync engine respects TTL, conditional gets, skipHour, and skipDay when specified by the feed.

updatePeriod and updateFrequency from the Syndication Module are not supported.