Module:HTMLParser/doc

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This is the documentation page for Module:HTMLParser

LuaRock "htmlparser"

Parse HTML text into a tree of elements with selectors

Install[edit]

Htmlparser is a listed LuaRock. Install using LuaRocks: luarocks install htmlparser

At Commons, everything you need is already in place. Module:Set, for example.

Dependencies[edit]

Htmlparser depends on Lua 5.2 5.1 (backported for Commons), and on the "set" LuaRock, which is installed along automatically. To be able to run the tests, lunitx (not available at Commons) also comes along as a LuaRock

Usage[edit]

Start off with 

local htmlparser = require("Module:HTMLParser")

Then, parse some html: 

local root = htmlparser.parse(htmlstring)

The input to parse may be the contents of a complete html document, or any valid html snippet, as long as all tags are correctly opened and closed. Now, find sepcific contained elements by selecting: 

local elements = root:select(selectorstring)

Or in shorthand: 

local elements = root(selectorstring)

This wil return a Set of elements, all of which are of the same type as the root element, and thus support selecting as well, if ever needed: 

for e in pairs(elements) do
	mw.log(e.name)
	local subs = e(subselectorstring)
	for sub in pairs(subs) do
		mw.log("", sub.name)
	end
end

The root element is a container for the top level elements in the parsed text, i.e. the <html> element in a parsed html document would be a child of the returned root element.

Selectors[edit]

Supported selectors are a subset of jQuery's selectors:

  • "*" all contained elements
  • "element" elements with the given tagname
  • "#id" elements with the given id attribute value
  • ".class" elements with the given classname in the class attribute
  • "[attribute]" elements with an attribute of the given name
  • "[attribute='value']" equals: elements with the given value for the given attribute
  • "[attribute!='value']" not equals: elements without the given attribute, or having the attribute, but with a different value
  • "[attribute|='value']" prefix: attribute's value is given value, or starts with given value, followed by a hyphen (-)
  • "[attribute*='value']" contains: attribute's value contains given value
  • "[attribute~='value']" word: attribute's value is a space-separated token, where one of the tokens is the given value
  • "[attribute^='value']" starts with: attribute's value starts with given value
  • "[attribute$='value']" ends with: attribute's value ends with given value
  • ":not(selectorstring)" elements not selected by given selector string
  • "ancestor descendant" elements selected by the descendant selector string, that are a descendant of any element selected by the ancestor selector string
  • "parent > child" elements selected by the child selector string, that are a child element of any element selected by the parent selector string

Selectors can be combined; e.g. ".class:not([attribute]) element.class"

Element type[edit]

All tree elements provide, apart from :select and (), the following accessors:

Basic[edit]

  • .name the element's tagname
  • .attributes a table with keys and values for the element's attributes; {} if none
  • .id the value of the element's id attribute; nil if not present
  • .classes an array with the classes listed in element's class attribute; {} if none
  • :getcontent() the raw text between the opening and closing tags of the element; "" if none
  • .nodes an array with the element's child elements, {} if none
  • .parent the elements that contains this element; root.parent is nil

Other[edit]

  • :gettext() the complete element text, starting with "<tagname" and ending with "/>" or "</tagname>"
  • .level how deep the element is in the tree; root level is 0
  • .root the root element of the tree; root.root is root
  • .deepernodes a Set containing all elements in the tree beneath this element, including this element's .nodes; {} if none
  • .deeperelements a table with a key for each distinct tagname in .deepernodes, containing a Set of all deeper element nodes with that name; {} in none
  • .deeperattributes as .deeperelements, but keyed on attribute name
  • .deeperids as .deeperelements, but keyed on id value
  • .deeperclasses as .deeperelements, but keyed on class name

Limitations[edit]

  • Attribute values in selector strings cannot contain any spaces, nor any of #, ., [, ], :, (, or )
  • The spaces before and after the > in a parent > child relation are mandatory
  • <! elements (including doctype, comments, and CDATA) are not parsed; markup within CDATA is *not* escaped
  • Textnodes are no seperate tree elements; in local root = htmlparser.parse("<p>line1<br />line2</p>"), root.nodes[1]:getcontent() is "line1<br />line2", while root.nodes[1].nodes[1].name is "br"
  • No start or end tags are implied when omitted. Only the void elements should not have an end tag
  • No validation is done for tag or attribute names or nesting of element types. The list of void elements is in fact the only part specific to HTML

Examples[edit]

See ./doc/sample.lua

Tests[edit]

See ./tst/init.lua

License[edit]

MIT; see ./doc/LICENSE

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