View source for representative-h-card-parsing

Assuming you already have access to a [[parsers#microformats2_parsers|microformats2 parser]], the algorithm defined here allows you to determine the representative [[h-card]] for a given page.

This algorithm is the microformats2 update to [[representative-hcard-parsing]].

== Algorithm ==

After [[parsing]] the page:

* If the page contains an h-card with '''uid''' and '''url''' properties both matching the page URL, the first such h-card is the representative h-card
* If no representative h-card was found, if the page contains an h-card with a '''url''' property value which also has a <code>rel=me</code> relation (i.e. matches a URL in parse_results.rels.me), the first such h-card is the representative h-card
* If no representative h-card was found, if the page contains '''one single''' h-card, and the h-card has a '''url''' property matching the page URL, that h-card is the representative h-card
* If no representative h-card was found, the page has no representative h-card

=== Matching URLs ===
URLs are to be matched as per the parsing algorithm defined in https://url.spec.whatwg.org:

* Parse the URLs
* If every component matches, the URLs match

== Implementations ==
Open source implementations of the representative h-card algorithm.

* '''PHP''' [https://github.com/barnabywalters/php-mf-cleaner barnabywalters/mf-cleaner] package implements representative h-card parsing in [https://github.com/barnabywalters/php-mf-cleaner/blob/master/src/BarnabyWalters/Mf2/Functions.php#L211 getRepresentativeHCard()] function
** Example usage: <code>$hcard = BarnabyWalters\Mf2\getRepresentativeHCard($mfs, $url);</code>
* Add yours here!
* …

== Back compat ==
All backcompat for representative h-card parsing should already be handled by the [[h-card#Backward_Compatibility|h-card backcompat]] rules, implemented by a conforming parser.

== See Also ==
* [[h-card]]
* [[representative-hcard]] — original hCard work, most of which applies equally to the updated algorithm