microformats2-parsing

<entry-title>microformats2 parsing</entry-title>

One of the goals of microformats2 is to greatly simplify parsing of microformats, in particular, by making parsing independent of any one vocabulary.

parsing algorithm

parse a document for microformats

To parse a document for microformats:

• start with an empty JSON items array
• parse the root element for microformats

parse an element for microformats

To parse an element for microformats:

• parse element class for root class name(s) "h-x" (and backcompat)
  • if found, start parsing a new microformat
    • parse contained elements for properties (depth first, doc order)
      • parse an element for microformats (recurse)
    • imply properties (see below)
• parse element class for properties (p-,dt-,u-,e-)
• add properties found (with any nested microformats) to current microformat

parsing a p- property

To parse an element for a p-x property value:

• parse the element for the value-class-pattern, if a value is found then return it.
• if abbr.p-x[title], then return the title attribute
• else if data.p-x[value], then return the value attribute
• else if br.p-x or hr.p-x, then return "" (empty string)
• else if img.p-x[alt] or area.p-x[alt], then return the alt attribute
• else return the innertext of the element.

parsing a u- property

To parse an element for a u-x property value:

• parse the element for the value-class-pattern, if a value is found then return it.
• if a.u-x[href] or area.u-x[href], then get the href attribute
• else if img.u-x[src], then get the src attribute
• else if object.u-x[data], then get the data attribute
• if there is a gotten value, return the normalized absolute URL of it, following the containing document's language's rules for resolving relative URLs.
• else if abbr.u-x[title], then return the title attribute
• else if data.u-x[value], then return the value attribute
• else return the innertext of the element.

parsing a dt- property

To parse an element for a dt-x property value:

• parse the element for the value-class-pattern including the date and time parsing rules, if a value is found then return it.
• if time.dt-x[datetime] or ins.dt-x[datetime] or del.dt-x[datetime], then return the datetime attribute
• else if abbr.dt-x[title], then return the title attribute
• else if data.dt-x[value], then return the value attribute
• else return the innertext of the element.

parsing an e- property

To parse an element for a e-x property value:

• return the innerHTML of the element by using the HTML spec: Serializing HTML Fragments algorithm.

parsing for implied properties

To imply properties: (where h-x is the root microformat element being parsed)

• if no explicit "name" property,
• then imply by:
  • if img.h-x then use its alt attribute for name
  • else if .h-x>img:only-node then use that img alt for name
  • else if .h-x>:only-node>img:only-node use that img alt for name
  • else use the innertext of the .h-x for name
  • drop leading & trailing white-space from name, including nbsp
• if no explicit "photo" property,
• then imply by:
  • if img.h-x[src] then use src for photo
  • else if .h-x>img[src]:only-of-type then use that img src for photo
  • else if .h-x>:only-child>img[src]:only-of-type then use that img src for photo
• if no explicit "url" property,
• then imply by:
  • if a.h-x[href] then use href for url
  • else if .h-x>a[href]:only-of-type then use that a[href] for url

what do the CSS selector expressions mean

Use SelectORacle to expand any of the above CSS selector expressions into longform English prose.

see also

• microformats2
• microformats2-implied-properties
• microformats2-parsing-brainstorming - for background, thinking, exploring possibilities