RSS enclosure explained

RSS enclosures are a way of attaching multimedia content to RSS feeds with the purpose of allowing that content to be prefetched.^[1] Enclosures provide the URL of a file associated with an entry, such as an MP3 file to a music recommendation or a photo to a diary entry. Unlike e-mail attachments, enclosures are merely hyperlinks to files. The actual file data is not embedded into the feed (unless a data URL is used). Support and implementation among aggregators varies: if the software understands the specified file format, it may automatically download and display the content, otherwise provide a link to it or silently ignore it.

The addition of enclosures to RSS, as first implemented by Dave Winer in late 2000 http://backend.userland.com/rss092, was an important prerequisite for the emergence of podcasting, perhaps the most common use of the feature . In podcasts and related technologies enclosures are not merely attachments to entries, but provide the main content of a feed.

Syntax

In RSS 2.0, the syntax for the tag, an optional child of the element, is as follows: where the value of the url attribute is a URL of a file, length is its size in bytes, and type its mime type.

It is recommended that only one element is included per <item>.^[2]

Prefetching

See main article: Link prefetching.

The RSS <enclosure> has similarities to:

• the SMIL <prefetch> element,
• the HTML <link> element with rel="prefetch".https://www.mozilla.org/projects/netlib/Link_Prefetching_FAQ.html
• the HTTP Link header with rel="prefetch". (See section 19.6.2.4.)
• the Atom <link> element with rel="enclosure"

See also

• Broadcatching
• Internet television
• Podcast
• Photofeed
• Vlog

External links

• The tag in the RSS 2.0 specification
• mod_enclosure - Enclosures in RSS 1.x
• Enclosure intended use case

Notes and References

1. Web site: RSS Enclosures Use Case. Rssboard.org. 3 October 2023.
2. Web site: RSS Best Practices Profile. Rssboard.org. 1 October 2017.