microformats2 parsing specification

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(incorporate resolved issues: deduping of rels and include alternates in rels)
(move now at-risk alternates part of algorithm to end to keep rels and rel-urls creating together per feedback from KevinMarks. change helps clarity without changing functionality)
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** if url is not in the array of the key rel-value in the rels hash then add url to the array
** if url is not in the array of the key rel-value in the rels hash then add url to the array
* end for
* end for
 +
* if there is no key with name url in the top-level "rel-urls" hash then add a key with name url there, with an empty hash value
 +
* add keys to the hash of the key with name url for each of these attributes (if present) and key not already set:
 +
** "hreflang": the value of the "hreflang" attribute
 +
** "media": the value of the "media" attribute
 +
** "title": the value of the "title" attribute
 +
** "type": the value of the "type" attribute
 +
** "text": the text content of the element if any
 +
* if there is no "rels" key in that hash, add it with an empty array value
 +
* set the value of that "rels" key to an array of all unique items in the set of rel values unioned with the current array value of the "rels" key
* if the set of rel values has "alternate" {{warn|this entire if clause may be dropped due to dropping alternates}}
* if the set of rel values has "alternate" {{warn|this entire if clause may be dropped due to dropping alternates}}
** if there's no top-level "alternates" array, then create it as an empty array.
** if there's no top-level "alternates" array, then create it as an empty array.
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*** "text": the text content of the element if any
*** "text": the text content of the element if any
* end if
* end if
-
* if there is no key with name url in the top-level "rel-urls" hash then add a key with name url there, with an empty hash value
 
-
* add keys to the hash of the key with name url for each of these attributes (if present) and key not already set:
 
-
** "hreflang": the value of the "hreflang" attribute
 
-
** "media": the value of the "media" attribute
 
-
** "title": the value of the "title" attribute
 
-
** "type": the value of the "type" attribute
 
-
** "text": the text content of the element if any
 
-
* if there is no "rels" key in that hash, add it with an empty array value
 
-
* set the value of that "rels" key to an array of all unique items in the set of rel values unioned with the current array value of the "rels" key
 
==== rel parse examples ====
==== rel parse examples ====

Revision as of 06:47, 6 June 2015


Tantek Çelik (Editor)


microformats2 is a simple, open format for marking up data in HTML. The microformats2 parsing specification describes how to implement a microformats2 parser.

One of the goals of microformats2 is to greatly simplify parsing of microformats, in particular, by making parsing independent of any one vocabulary. This specification documents the microformats2 parsing algorithm for doing so.

Per CC0, to the extent possible under law, the editors have waived all copyright and related or neighboring rights to this work. In addition, as of 2017-11-18, the editors have made this specification available under the Open Web Foundation Agreement Version 1.0.

Contents

algorithm

parse a document for microformats

To parse a document for microformats, follow the HTML parsing rules and do the following:

{
 "items": [],
 "rels": {},
 "rel-urls": {}
}

Parsers may simultaneously parse the document for both class and rel microformats (e.g. in a single tree traversal).

parse an element for class microformats

To parse an element for class microformats:

parse an element for properties

parsing a p- property

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

parsing a u- property

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

parsing a dt- property

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

parsing an e- property

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

parsing for implied properties

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

Note: The same markup for a property should not be causing that property to occur in both a microformat and one embedded inside - such a property should only be showing up on one of them. The parsing algorithm has details to prevent that, such as the :not[.h-*] tests above.

parse a hyperlink element for rel microformats

To parse a hyperlink element for rel microformats: (where * is the hyperlink element), use the following algorithm or an algorithm that produces equivalent results:

rel parse examples

Here are some examples to show how parsed rels may be reflected into the JSON (empty items key).

E.g. parsing this markup:

<a rel="author" href="http://example.com/a">author a</a>
<a rel="author" href="http://example.com/b">author b</a>
<a rel="in-reply-to" href="http://example.com/1">post 1</a>
<a rel="in-reply-to" href="http://example.com/2">post 2</a>
<a rel="alternate home"
   href="http://example.com/fr"
   media="handheld"
   hreflang="fr">French mobile homepage</a>

Would generate this JSON:

{
  "items": [],
  "rels": { 
    "author": [ "http://example.com/a", "http://example.com/b" ],
    "in-reply-to": [ "http://example.com/1", "http://example.com/2" ],
    "alternate": [ "http://example.com/fr" ], 
    "home": [ "http://example.com/fr" ] 
  },
  "rel-urls": {
    "http://example.com/a": {
      "rels": ["author"], 
      "text": "author a"
    },
    "http://example.com/b": {
      "rels": ["author"], 
      "text": "author b"
    },
    "http://example.com/1": {
      "rels": ["in-reply-to"], 
      "text": "post 1"
    },
    "http://example.com/2": {
      "rels": ["in-reply-to"], 
      "text": "post 2"
    },
    "http://example.com/fr": {
      "rels": ["alternate", "home"],
      "media": "handheld", 
      "hreflang": "fr", 
      "text": "French mobile homepage"
    }
  }
  "alternates": [{
     "url": "http://example.com/fr", 
     "rel": "home", 
     "media": "handheld", 
     "hreflang": "fr",
     "text": "French mobile homepage"
  }]
}
Warning: The "alternates" collection is likely to be dropped. Use "rel-urls" instead.


what do the CSS selector expressions mean

This section is non-normative.

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

Exception:

note HTML parsing rules

This section is non-normative.

microformats2 parsers are expected to follow HTML parsing rules, which includes for example:

questions

See the FAQ:

issues

See the issues page:

implementations

Main article: microformats2#Implementations

There are open source microformats2 parsers available for Javascript, node.js, PHP, Ruby and Python.

test suite

See:

Ports to/for other languages encouraged.

see also

Categories

microformats2 parsing specification was last modified: Wednesday, December 31st, 1969

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