Feeds Date Elements Mapping to SyndFeed and SyndEntry

The different RSS versions and Atom define different date elements at feed and entry level. Some of them also define syndication information indicating when (and when not) and how often to fetch feeds for updates. There is not always a possible mapping or conversion of this information when going from one format to another.

As this is still subject of debate (How About a Date and Date Survey), for now, in Rss and atOM utilitiEs (ROME) we've taken a simplistic approach.

When handling feeds at WireFeed level, rss.Channel or atom.Feed, it is possible to access all the date elements and syndication information available in the feed.

When handling feeds at SyndFeed level, synd.SyndFeed, there is only one date element available, the publishedDate. Both, SyndFeed and SyndEntry have the publisheDate property. In addition, it is possible to use the Syndication Module.

The mapping of the date elements from the different feed formats to SyndFeed is as follows.

For RSS 0.90

RSS 0.90 does not define date elements.

There is no mapping to SyndFeed and SyndEntry date properties.

For RSS 0.91, 0.92

RSS 0.91 and 0.92 define pubDate and lastBuildDate at feed level.

The feed pubDate element is mapped to the SyndFeed publishedDate property. The lastBuildDate element is lost.

For RSS 0.93, 0.94 and 2.0

RSS 0.93, 0.94 and 2.0 define pubDate and lastBuildDate at feed level. They also define pubDate and expirationDate at item level.

The feed pubDate element is mapped to the SyndFeed publishedDate property. The lastBuildDate element is lost.

The item pubDate element is mapped to the SyndEntry publishedDate property. The expirationDate element is lost.

For RSS 1.0

RSS 1.0 use DC Module data at feed an item level to indicate date information about the feed and the items.

SyndFeed and SyndEntry use the DC Module date element for the publishedDate property.

For Atom 0.3

Atom 0.3 defines a modified element at feed level and the modified, created & issued elements at entry level.

The feed modified element is mapped to the SyndFeed publishedDate property.

The item modified element is mapped to the SyndEntry publishedDate property. The entry elements, created and issued, are lost.

For Atom 1.0

(Atom 1.0 supported in ROME since v0.8)

Atom 1.0 defines an updated element at the feed level, which ROME maps to SyndFeed.publishedDate.

Atom 1.0 defines updated and published elements at the entry level, which ROME maps to SyndEntry.updatedDate and SyndEntry.publishedDate respectively.