Class: Arbre::Html::Query

Inherits:
Object
  • Object
show all
Defined in:
lib/arbre/html/querying.rb

Overview

Class to find tags from a given root tag / element based on a CSS-like query.

Constant Summary collapse

CSS_IDENTIFIER =

This constant is part of a private API. You should avoid using this constant if possible, as it may be removed or be changed in the future. 

/[-_a-z][-_a-z0-9]*/
CSS_SCAN =

This constant is part of a private API. You should avoid using this constant if possible, as it may be removed or be changed in the future. 

%r[

  # Child node operator
  (>)?

  \s*

  (?:

    (\*)

    |

    # Tag name
    (#{CSS_IDENTIFIER})?

    # ID
    (?:\#(#{CSS_IDENTIFIER}))?

    # Class
    ((?:\.#{CSS_IDENTIFIER})+)?

    # Pseudo
    ((?::#{CSS_IDENTIFIER})+)?

    # Attributes
    ((?:\[.+?\])+)?

  )

]x

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(root) ⇒ Query

Initialization



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# File 'lib/arbre/html/querying.rb', line 104

def initialize(root)
  @root = root
end

Instance Attribute Details

#root ⇒ Object (readonly)

Returns the value of attribute root.



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# File 'lib/arbre/html/querying.rb', line 108

def root
  @root
end

Instance Method Details

#execute(query) ⇒ Object

Executes the given query.



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# File 'lib/arbre/html/querying.rb', line 153

def execute(query)
  # Sanitize the query for processing.
  query = query.downcase.squeeze(' ')

  result = []

  selectors = query.split(',').map(&:strip).reject(&:blank?)

  selectors.map do |selector|
    tags = [ root ]

    # Run through all segments in the selector and process them one by one.
    selector.scan CSS_SCAN do |operator, all, tag, id, classes, pseudos, attributes|
      next unless all || tag || id || classes || pseudos || attributes

      classes = classes.split('.').reject(&:blank?) if classes
      pseudos = pseudos.split(':').reject(&:blank?) if pseudos

      # First process combinations of operator, all and id.
      tags = case operator
      when '>' then find_children(tags, tag, id, classes)
      else find_descendants(tags, tag, id, classes)
      end

      filter_by_pseudos tags, pseudos if pseudos
      filter_by_attributes tags, attributes if attributes
    end

    result.concat tags
  end

  # Convert to an element collection.
  ElementCollection.new(result)
end