Class: HTML::Tag
- Defined in:
- lib/action_controller/vendor/html-scanner/html/node.rb
Overview
A Tag is any node that represents markup. It may be an opening tag, a closing tag, or a self-closing tag. It has a name, and may have a hash of attributes.
Instance Attribute Summary collapse
-
#attributes ⇒ Object
readonly
Either
nil
, or a hash of attributes for this node. -
#closing ⇒ Object
readonly
Either
nil
,:close
, or:self
. -
#name ⇒ Object
readonly
The name of this tag.
Attributes inherited from Node
#children, #line, #parent, #position
Instance Method Summary collapse
-
#[](attr) ⇒ Object
A convenience for obtaining an attribute of the node.
-
#childless? ⇒ Boolean
Returns non-
nil
if this tag can contain child nodes. -
#find(conditions) ⇒ Object
If either the node or any of its children meet the given conditions, the matching node is returned.
-
#initialize(parent, line, pos, name, attributes, closing) ⇒ Tag
constructor
Create a new node as a child of the given parent, using the given content to describe the node.
-
#match(conditions) ⇒ Object
Returns
true
if the node meets any of the given conditions. -
#tag? ⇒ Boolean
Returns
true
, indicating that this node represents an HTML tag. -
#to_s ⇒ Object
Returns a textual representation of the node.
Methods inherited from Node
#find_all, parse, #validate_conditions
Constructor Details
#initialize(parent, line, pos, name, attributes, closing) ⇒ Tag
Create a new node as a child of the given parent, using the given content to describe the node. It will be parsed and the node name, attributes and closing status extracted.
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# File 'lib/action_controller/vendor/html-scanner/html/node.rb', line 260 def initialize(parent, line, pos, name, attributes, closing) super(parent, line, pos) @name = name @attributes = attributes @closing = closing end |
Instance Attribute Details
#attributes ⇒ Object (readonly)
Either nil
, or a hash of attributes for this node.
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# File 'lib/action_controller/vendor/html-scanner/html/node.rb', line 252 def attributes @attributes end |
#closing ⇒ Object (readonly)
Either nil
, :close
, or :self
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# File 'lib/action_controller/vendor/html-scanner/html/node.rb', line 249 def closing @closing end |
#name ⇒ Object (readonly)
The name of this tag.
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# File 'lib/action_controller/vendor/html-scanner/html/node.rb', line 255 def name @name end |
Instance Method Details
#[](attr) ⇒ Object
A convenience for obtaining an attribute of the node. Returns nil
if the node has no attributes.
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# File 'lib/action_controller/vendor/html-scanner/html/node.rb', line 269 def [](attr) @attributes ? @attributes[attr] : nil end |
#childless? ⇒ Boolean
Returns non-nil
if this tag can contain child nodes.
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# File 'lib/action_controller/vendor/html-scanner/html/node.rb', line 274 def childless? !@closing.nil? || @name =~ /^(img|br|hr|link|meta|area|base|basefont| col|frame|input|isindex|param)$/ox end |
#find(conditions) ⇒ Object
If either the node or any of its children meet the given conditions, the matching node is returned. Otherwise, nil
is returned. (See the description of the valid conditions in the match
method.)
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# File 'lib/action_controller/vendor/html-scanner/html/node.rb', line 301 def find(conditions) match(conditions) && self || super end |
#match(conditions) ⇒ Object
Returns true
if the node meets any of the given conditions. The conditions
parameter must be a hash of any of the following keys (all are optional):
-
:tag
: the node name must match the corresponding value -
:attributes
: a hash. The node’s values must match the corresponding values in the hash. -
:parent
: a hash. The node’s parent must match the corresponding hash. -
:child
: a hash. At least one of the node’s immediate children must meet the criteria described by the hash. -
:ancestor
: a hash. At least one of the node’s ancestors must meet the criteria described by the hash. -
:descendant
: a hash. At least one of the node’s descendants must meet the criteria described by the hash. -
:sibling
: a hash. At least one of the node’s siblings must meet the criteria described by the hash. -
:after
: a hash. The node must be after any sibling meeting the criteria described by the hash, and at least one sibling must match. -
:before
: a hash. The node must be before any sibling meeting the criteria described by the hash, and at least one sibling must match. -
:children
: a hash, for counting children of a node. Accepts the keys:
** :count
: either a number or a range which must equal (or
include) the number of children that match.
** :less_than
: the number of matching children must be less than
this number.
** :greater_than
: the number of matching children must be
greater than this number.
** :only
: another hash consisting of the keys to use
to match on the children, and only matching children will be
counted.
Conditions are matched using the following algorithm:
-
if the condition is a string, it must be a substring of the value.
-
if the condition is a regexp, it must match the value.
-
if the condition is a number, the value must match number.to_s.
-
if the condition is
true
, the value must not benil
. -
if the condition is
false
ornil
, the value must benil
.
Usage:
# test if the node is a "span" tag
node.match :tag => "span"
# test if the node's parent is a "div"
node.match :parent => { :tag => "div" }
# test if any of the node's ancestors are "table" tags
node.match :ancestor => { :tag => "table" }
# test if any of the node's immediate children are "em" tags
node.match :child => { :tag => "em" }
# test if any of the node's descendants are "strong" tags
node.match :descendant => { :tag => "strong" }
# test if the node has between 2 and 4 span tags as immediate children
node.match :children => { :count => 2..4, :only => { :tag => "span" } }
# get funky: test to see if the node is a "div", has a "ul" ancestor
# and an "li" parent (with "class" = "enum"), and whether or not it has
# a "span" descendant that contains # text matching /hello world/:
node.match :tag => "div",
:ancestor => { :tag => "ul" },
:parent => { :tag => "li",
:attributes => { :class => "enum" } },
:descendant => { :tag => "span",
:child => /hello world/ }
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# File 'lib/action_controller/vendor/html-scanner/html/node.rb', line 380 def match(conditions) conditions = validate_conditions(conditions) # check content of child nodes return false unless children.find { |child| child.match(conditions[:content]) } if conditions[:content] # test the name return false unless match_condition(@name, conditions[:tag]) if conditions[:tag] # test attributes (conditions[:attributes] || {}).each do |key, value| return false unless match_condition(self[key], value) end # test parent return false unless parent.match(conditions[:parent]) if conditions[:parent] # test children return false unless children.find { |child| child.match(conditions[:child]) } if conditions[:child] # test ancestors if conditions[:ancestor] return false unless catch :found do p = self throw :found, true if p.match(conditions[:ancestor]) while p = p.parent end end # test descendants if conditions[:descendant] return false unless children.find do |child| # test the child child.match(conditions[:descendant]) || # test the child's descendants child.match(:descendant => conditions[:descendant]) end end # count children if opts = conditions[:children] matches = children matches = matches.select { |c| c.match(opts[:only]) } if opts[:only] opts.each do |key, value| next if key == :only case key when :count if Integer === value return false if matches.length != value else return false unless value.include?(matches.length) end when :less_than return false unless matches.length < value when :greater_than return false unless matches.length > value else raise "unknown count condition #{key}" end end end # test siblings if conditions[:sibling] || conditions[:before] || conditions[:after] siblings = parent ? parent.children : [] self_index = siblings.index(self) if conditions[:sibling] return false unless siblings.detect do |s| s != self && s.match(conditions[:sibling]) end end if conditions[:before] return false unless siblings[self_index+1..-1].detect do |s| s != self && s.match(conditions[:before]) end end if conditions[:after] return false unless siblings[0,self_index].detect do |s| s != self && s.match(conditions[:after]) end end end true end |
#tag? ⇒ Boolean
Returns true
, indicating that this node represents an HTML tag.
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# File 'lib/action_controller/vendor/html-scanner/html/node.rb', line 306 def tag? true end |
#to_s ⇒ Object
Returns a textual representation of the node
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# File 'lib/action_controller/vendor/html-scanner/html/node.rb', line 281 def to_s if @closing == :close "</#{@name}>" else s = "<#{@name}" @attributes.each do |k,v| s << " #{k}" s << "='#{v.gsub(/'/,"\\\\'")}'" if String === v end s << " /" if @closing == :self s << ">" @children.each { |child| s << child.to_s } s << "</#{@name}>" if @closing != :self && !@children.empty? s end end |