feed URI scheme
In computing, the feed: URI scheme (sometimes referred to, somewhat imprecisely, as the feed protocol; see Protocol (computing)) is a non-standard URI scheme designed to facilitate subscription to web feeds; specifically, it is intended that a news aggregator be launched whenever a hyperlink to a feed: URI is clicked in a web browser.
The scheme is used to flag a document in a syndication format such as Atom or RSS. The document is served over HTTP.
Critics hold that the purpose of the feed: URI scheme is better served by MIME types,[1] or that it is not a user-friendly solution for the problem of feed subscription, since a user who has not installed the appropriate software will receive an unhelpful browser error message on clicking a link to a feed: URI.
The feed: URI scheme is currently supported by several popular desktop aggregators, including NetNewsWire, FeedDemon, Safari, and Flock, although as of 2006[update] no effort seems to be underway to officially register the scheme with a standards body.[citation needed]
Syntax
The syntax for a feed: URI may be expressed in Backus–Naur form as follows:
<feed_uri> ::= "feed:" <absolute_uri> | "feed://" <hier_part>
Specifically, a feed: URI may be formed from any absolute URI (such as an absolute URL) by prepending feed:, and as a special case, may be formed from any absolute http: URI by replacing the initial http:// with feed://. Therefore, the following are two examples of valid feed: URIs:
feed://example.com/rss.xml feed:https://example.com/rss.xml
There is also a proposed extension of the syntax that supports metadata and embedded instructions to the aggregator.[2]
References
External links
- The feed URI scheme — pre-draft version of a specification from 2004
- The feed protocol format — including proposal for extensions