XSS Security fixes
This commit is contained in:
Jacques Distler
parent
c9a9b7d315
commit
552cf4cff0
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@ -24,36 +24,48 @@ module Engines
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end
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class Textile < AbstractEngine
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require_dependency 'sanitize'
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include Sanitize
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def mask
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require_dependency 'redcloth'
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redcloth = RedCloth.new(@content, [:hard_breaks] + @content.options[:engine_opts])
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redcloth.filter_html = false
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redcloth.no_span_caps = false
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redcloth.to_html(:textile)
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html = redcloth.to_html(:textile)
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sanitize_html(html)
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end
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end
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class Markdown < AbstractEngine
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require_dependency 'sanitize'
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include Sanitize
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def mask
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require_dependency 'bluecloth_tweaked'
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BlueCloth.new(@content, @content.options[:engine_opts]).to_html
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html = BlueCloth.new(@content, @content.options[:engine_opts]).to_html
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sanitize_html(html)
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end
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end
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class Mixed < AbstractEngine
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require_dependency 'sanitize'
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include Sanitize
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def mask
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require_dependency 'redcloth'
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redcloth = RedCloth.new(@content, @content.options[:engine_opts])
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redcloth.filter_html = false
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redcloth.no_span_caps = false
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redcloth.to_html
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html = redcloth.to_html
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sanitize_html(html)
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end
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end
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class RDoc < AbstractEngine
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require_dependency 'sanitize'
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include Sanitize
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def mask
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require_dependency 'rdocsupport'
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RDocSupport::RDocFormatter.new(@content).to_html
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html = RDocSupport::RDocFormatter.new(@content).to_html
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sanitize_html(html)
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end
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end
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530
lib/node.rb
Normal file
530
lib/node.rb
Normal file
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@ -0,0 +1,530 @@
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require 'strscan'
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module XHTML #:nodoc:
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class Conditions < Hash #:nodoc:
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def initialize(hash)
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super()
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hash = { :content => hash } unless Hash === hash
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hash = keys_to_symbols(hash)
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hash.each do |k,v|
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case k
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when :tag, :content then
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# keys are valid, and require no further processing
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when :attributes then
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hash[k] = keys_to_strings(v)
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when :parent, :child, :ancestor, :descendant, :sibling, :before,
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:after
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hash[k] = Conditions.new(v)
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when :children
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hash[k] = v = keys_to_symbols(v)
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v.each do |k,v2|
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case k
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when :count, :greater_than, :less_than
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# keys are valid, and require no further processing
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when :only
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v[k] = Conditions.new(v2)
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else
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raise "illegal key #{k.inspect} => #{v2.inspect}"
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end
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end
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else
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raise "illegal key #{k.inspect} => #{v.inspect}"
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end
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end
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update hash
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end
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private
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def keys_to_strings(hash)
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hash.keys.inject({}) do |h,k|
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h[k.to_s] = hash[k]
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h
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end
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end
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def keys_to_symbols(hash)
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hash.keys.inject({}) do |h,k|
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raise "illegal key #{k.inspect}" unless k.respond_to?(:to_sym)
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h[k.to_sym] = hash[k]
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h
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end
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end
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end
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# The base class of all nodes, textual and otherwise, in an HTML document.
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class Node #:nodoc:
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# The array of children of this node. Not all nodes have children.
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attr_reader :children
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# The parent node of this node. All nodes have a parent, except for the
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# root node.
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attr_reader :parent
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# The line number of the input where this node was begun
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attr_reader :line
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# The byte position in the input where this node was begun
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attr_reader :position
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# Create a new node as a child of the given parent.
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def initialize(parent, line=0, pos=0)
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@parent = parent
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@children = []
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@line, @position = line, pos
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end
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# Return a textual representation of the node.
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def to_s
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s = ""
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@children.each { |child| s << child.to_s }
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s
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end
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# Return false (subclasses must override this to provide specific matching
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# behavior.) +conditions+ may be of any type.
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def match(conditions)
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false
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end
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# Search the children of this node for the first node for which #find
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# returns non +nil+. Returns the result of the #find call that succeeded.
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def find(conditions)
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conditions = validate_conditions(conditions)
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@children.each do |child|
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node = child.find(conditions)
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return node if node
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end
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nil
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end
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# Search for all nodes that match the given conditions, and return them
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# as an array.
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def find_all(conditions)
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conditions = validate_conditions(conditions)
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matches = []
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matches << self if match(conditions)
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@children.each do |child|
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matches.concat child.find_all(conditions)
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end
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matches
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end
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# Returns +false+. Subclasses may override this if they define a kind of
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# tag.
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def tag?
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false
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end
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def validate_conditions(conditions)
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Conditions === conditions ? conditions : Conditions.new(conditions)
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end
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def ==(node)
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return false unless self.class == node.class && children.size == node.children.size
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equivalent = true
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children.size.times do |i|
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equivalent &&= children[i] == node.children[i]
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end
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equivalent
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end
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class <<self
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def parse(parent, line, pos, content, strict=true)
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if content !~ /^<\S/
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Text.new(parent, line, pos, content)
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else
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scanner = StringScanner.new(content)
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unless scanner.skip(/</)
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if strict
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raise "expected <"
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else
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return Text.new(parent, line, pos, content)
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end
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end
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if scanner.skip(/!\[CDATA\[/)
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scanner.scan_until(/\]\]>/)
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return CDATA.new(parent, line, pos, scanner.pre_match.gsub(/<!\[CDATA\[/, ''))
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end
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closing = ( scanner.scan(/\//) ? :close : nil )
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return Text.new(parent, line, pos, content) unless name = scanner.scan(/[\w:-]+/)
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name
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unless closing
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scanner.skip(/\s*/)
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attributes = {}
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while attr = scanner.scan(/[-\w:]+/)
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value = true
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if scanner.scan(/\s*=\s*/)
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if delim = scanner.scan(/['"]/)
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value = ""
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while text = scanner.scan(/[^#{delim}\\]+|./)
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case text
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when "\\" then
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value << text
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value << scanner.getch
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when delim
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break
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else value << text
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end
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end
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else
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value = scanner.scan(/[^\s>\/]+/)
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end
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end
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attributes[attr] = value
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scanner.skip(/\s*/)
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end
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closing = ( scanner.scan(/\//) ? :self : nil )
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end
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unless scanner.scan(/\s*>/)
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if strict
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raise "expected > (got #{scanner.rest.inspect} for #{content}, #{attributes.inspect})"
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else
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# throw away all text until we find what we're looking for
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scanner.skip_until(/>/) or scanner.terminate
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end
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end
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Tag.new(parent, line, pos, name, attributes, closing)
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end
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end
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end
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end
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# A node that represents text, rather than markup.
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class Text < Node #:nodoc:
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attr_reader :content
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# Creates a new text node as a child of the given parent, with the given
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# content.
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def initialize(parent, line, pos, content)
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super(parent, line, pos)
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@content = content
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end
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# Returns the content of this node.
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def to_s
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@content
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end
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# Returns +self+ if this node meets the given conditions. Text nodes support
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# conditions of the following kinds:
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#
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# * if +conditions+ is a string, it must be a substring of the node's
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# content
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# * if +conditions+ is a regular expression, it must match the node's
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# content
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# * if +conditions+ is a hash, it must contain a <tt>:content</tt> key that
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# is either a string or a regexp, and which is interpreted as described
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# above.
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def find(conditions)
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match(conditions) && self
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end
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# Returns non-+nil+ if this node meets the given conditions, or +nil+
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# otherwise. See the discussion of #find for the valid conditions.
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def match(conditions)
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case conditions
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when String
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@content == conditions
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when Regexp
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@content =~ conditions
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when Hash
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conditions = validate_conditions(conditions)
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# Text nodes only have :content, :parent, :ancestor
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unless (conditions.keys - [:content, :parent, :ancestor]).empty?
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return false
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end
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match(conditions[:content])
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else
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nil
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end
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end
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def ==(node)
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return false unless super
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content == node.content
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end
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end
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# A CDATA node is simply a text node with a specialized way of displaying
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# itself.
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class CDATA < Text #:nodoc:
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def to_s
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"<![CDATA[#{super}]>"
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end
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end
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# A Tag is any node that represents markup. It may be an opening tag, a
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# closing tag, or a self-closing tag. It has a name, and may have a hash of
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# attributes.
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class Tag < Node #:nodoc:
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# Either +nil+, <tt>:close</tt>, or <tt>:self</tt>
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attr_reader :closing
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# Either +nil+, or a hash of attributes for this node.
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attr_reader :attributes
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# The name of this tag.
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attr_reader :name
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# Create a new node as a child of the given parent, using the given content
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# to describe the node. It will be parsed and the node name, attributes and
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# closing status extracted.
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def initialize(parent, line, pos, name, attributes, closing)
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super(parent, line, pos)
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@name = name
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@attributes = attributes
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@closing = closing
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end
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# A convenience for obtaining an attribute of the node. Returns +nil+ if
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# the node has no attributes.
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def [](attr)
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@attributes ? @attributes[attr] : nil
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end
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# Returns non-+nil+ if this tag can contain child nodes.
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def childless?(xml = false)
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return false if xml && @closing.nil?
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!@closing.nil? ||
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@name =~ /^(img|br|hr|link|meta|area|base|basefont|
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col|frame|input|isindex|param)$/ox
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end
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# Returns a textual representation of the node
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def to_s
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if @closing == :close
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"</#{@name}>"
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else
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s = "<#{@name}"
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@attributes.each do |k,v|
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s << " #{k}"
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s << "=\"#{v}\"" if String === v
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end
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s << " /" if @closing == :self
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s << ">"
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@children.each { |child| s << child.to_s }
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s << "</#{@name}>" if @closing != :self && !@children.empty?
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s
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end
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end
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# If either the node or any of its children meet the given conditions, the
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# matching node is returned. Otherwise, +nil+ is returned. (See the
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# description of the valid conditions in the +match+ method.)
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def find(conditions)
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match(conditions) && self || super
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end
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# Returns +true+, indicating that this node represents an HTML tag.
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def tag?
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true
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end
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# Returns +true+ if the node meets any of the given conditions. The
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# +conditions+ parameter must be a hash of any of the following keys
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# (all are optional):
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#
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# * <tt>:tag</tt>: the node name must match the corresponding value
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# * <tt>:attributes</tt>: a hash. The node's values must match the
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# corresponding values in the hash.
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# * <tt>:parent</tt>: a hash. The node's parent must match the
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# corresponding hash.
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# * <tt>:child</tt>: a hash. At least one of the node's immediate children
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# must meet the criteria described by the hash.
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# * <tt>:ancestor</tt>: a hash. At least one of the node's ancestors must
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# meet the criteria described by the hash.
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# * <tt>:descendant</tt>: a hash. At least one of the node's descendants
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# must meet the criteria described by the hash.
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# * <tt>:sibling</tt>: a hash. At least one of the node's siblings must
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# meet the criteria described by the hash.
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# * <tt>:after</tt>: a hash. The node must be after any sibling meeting
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# the criteria described by the hash, and at least one sibling must match.
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# * <tt>:before</tt>: a hash. The node must be before any sibling meeting
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# the criteria described by the hash, and at least one sibling must match.
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# * <tt>:children</tt>: a hash, for counting children of a node. Accepts the
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# keys:
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# ** <tt>:count</tt>: either a number or a range which must equal (or
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# include) the number of children that match.
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# ** <tt>:less_than</tt>: the number of matching children must be less than
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# this number.
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# ** <tt>:greater_than</tt>: the number of matching children must be
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# greater than this number.
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# ** <tt>:only</tt>: another hash consisting of the keys to use
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# to match on the children, and only matching children will be
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# counted.
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#
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# Conditions are matched using the following algorithm:
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#
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# * if the condition is a string, it must be a substring of the value.
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# * if the condition is a regexp, it must match the value.
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# * if the condition is a number, the value must match number.to_s.
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# * if the condition is +true+, the value must not be +nil+.
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# * if the condition is +false+ or +nil+, the value must be +nil+.
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#
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# Usage:
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#
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# # test if the node is a "span" tag
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# node.match :tag => "span"
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#
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# # test if the node's parent is a "div"
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# node.match :parent => { :tag => "div" }
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#
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# # test if any of the node's ancestors are "table" tags
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# node.match :ancestor => { :tag => "table" }
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#
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# # test if any of the node's immediate children are "em" tags
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# node.match :child => { :tag => "em" }
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#
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# # test if any of the node's descendants are "strong" tags
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# node.match :descendant => { :tag => "strong" }
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#
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# # test if the node has between 2 and 4 span tags as immediate children
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# node.match :children => { :count => 2..4, :only => { :tag => "span" } }
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#
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# # get funky: test to see if the node is a "div", has a "ul" ancestor
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# # and an "li" parent (with "class" = "enum"), and whether or not it has
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# # a "span" descendant that contains # text matching /hello world/:
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# node.match :tag => "div",
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# :ancestor => { :tag => "ul" },
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# :parent => { :tag => "li",
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# :attributes => { :class => "enum" } },
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# :descendant => { :tag => "span",
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# :child => /hello world/ }
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def match(conditions)
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conditions = validate_conditions(conditions)
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# check content of child nodes
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if conditions[:content]
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if children.empty?
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return false unless match_condition("", conditions[:content])
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else
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return false unless children.find { |child| child.match(conditions[:content]) }
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end
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end
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# test the name
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return false unless match_condition(@name, conditions[:tag]) if conditions[:tag]
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# test attributes
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(conditions[:attributes] || {}).each do |key, value|
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return false unless match_condition(self[key], value)
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end
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# test parent
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return false unless parent.match(conditions[:parent]) if conditions[:parent]
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# test children
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return false unless children.find { |child| child.match(conditions[:child]) } if conditions[:child]
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# test ancestors
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if conditions[:ancestor]
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return false unless catch :found do
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p = self
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throw :found, true if p.match(conditions[:ancestor]) while p = p.parent
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end
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end
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# test descendants
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if conditions[:descendant]
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return false unless children.find do |child|
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# test the child
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child.match(conditions[:descendant]) ||
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# test the child's descendants
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child.match(:descendant => conditions[:descendant])
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end
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end
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# count children
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if opts = conditions[:children]
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matches = children.select do |c|
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(c.kind_of?(HTML::Tag) and (c.closing == :self or ! c.childless?))
|
||||
end
|
||||
|
||||
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
|
||||
|
||||
def ==(node)
|
||||
return false unless super
|
||||
return false unless closing == node.closing && self.name == node.name
|
||||
attributes == node.attributes
|
||||
end
|
||||
|
||||
private
|
||||
# Match the given value to the given condition.
|
||||
def match_condition(value, condition)
|
||||
case condition
|
||||
when String
|
||||
value && value == condition
|
||||
when Regexp
|
||||
value && value.match(condition)
|
||||
when Numeric
|
||||
value == condition.to_s
|
||||
when true
|
||||
!value.nil?
|
||||
when false, nil
|
||||
value.nil?
|
||||
else
|
||||
false
|
||||
end
|
||||
end
|
||||
end
|
||||
end
|
||||
205
lib/sanitize.rb
Normal file
205
lib/sanitize.rb
Normal file
|
|
@ -0,0 +1,205 @@
|
|||
module Sanitize
|
||||
|
||||
# This module provides sanitization of XHTML+MathML+SVG
|
||||
# and of inline style attributes.
|
||||
#
|
||||
# Based heavily on Sam Ruby's code in the Universal FeedParser.
|
||||
|
||||
require 'html/tokenizer'
|
||||
require 'node'
|
||||
|
||||
acceptable_elements = ['a', 'abbr', 'acronym', 'address', 'area', 'b',
|
||||
'big', 'blockquote', 'br', 'button', 'caption', 'center', 'cite',
|
||||
'code', 'col', 'colgroup', 'dd', 'del', 'dfn', 'dir', 'div', 'dl', 'dt',
|
||||
'em', 'fieldset', 'font', 'form', 'h1', 'h2', 'h3', 'h4', 'h5', 'h6',
|
||||
'hr', 'i', 'img', 'input', 'ins', 'kbd', 'label', 'legend', 'li', 'map',
|
||||
'menu', 'ol', 'optgroup', 'option', 'p', 'pre', 'q', 's', 'samp',
|
||||
'select', 'small', 'span', 'strike', 'strong', 'sub', 'sup', 'table',
|
||||
'tbody', 'td', 'textarea', 'tfoot', 'th', 'thead', 'tr', 'tt', 'u',
|
||||
'ul', 'var']
|
||||
|
||||
mathml_elements = ['maction', 'math', 'merror', 'mfrac', 'mi',
|
||||
'mmultiscripts', 'mn', 'mo', 'mover', 'mpadded', 'mphantom',
|
||||
'mprescripts', 'mroot', 'mrow', 'mspace', 'msqrt', 'mstyle', 'msub',
|
||||
'msubsup', 'msup', 'mtable', 'mtd', 'mtext', 'mtr', 'munder',
|
||||
'munderover', 'none']
|
||||
|
||||
svg_elements = ['a', 'animate', 'animateColor', 'animateMotion',
|
||||
'animateTransform', 'circle', 'defs', 'desc', 'ellipse', 'font-face',
|
||||
'font-face-name', 'font-face-src', 'g', 'glyph', 'hkern', 'image',
|
||||
'linearGradient', 'line', 'metadata', 'missing-glyph', 'mpath', 'path',
|
||||
'polygon', 'polyline', 'radialGradient', 'rect', 'set', 'stop', 'svg',
|
||||
'switch', 'text', 'title', 'use']
|
||||
|
||||
acceptable_attributes = ['abbr', 'accept', 'accept-charset', 'accesskey',
|
||||
'action', 'align', 'alt', 'axis', 'border', 'cellpadding',
|
||||
'cellspacing', 'char', 'charoff', 'charset', 'checked', 'cite', 'class',
|
||||
'clear', 'cols', 'colspan', 'color', 'compact', 'coords', 'datetime',
|
||||
'dir', 'disabled', 'enctype', 'for', 'frame', 'headers', 'height',
|
||||
'href', 'hreflang', 'hspace', 'id', 'ismap', 'label', 'lang',
|
||||
'longdesc', 'maxlength', 'media', 'method', 'multiple', 'name',
|
||||
'nohref', 'noshade', 'nowrap', 'prompt', 'readonly', 'rel', 'rev',
|
||||
'rows', 'rowspan', 'rules', 'scope', 'selected', 'shape', 'size',
|
||||
'span', 'src', 'start', 'style', 'summary', 'tabindex', 'target', 'title',
|
||||
'type', 'usemap', 'valign', 'value', 'vspace', 'width', 'xml:lang']
|
||||
|
||||
|
||||
mathml_attributes = ['actiontype', 'align', 'columnalign', 'columnalign',
|
||||
'columnalign', 'columnlines', 'columnspacing', 'columnspan', 'depth',
|
||||
'display', 'displaystyle', 'equalcolumns', 'equalrows', 'fence',
|
||||
'fontstyle', 'fontweight', 'frame', 'height', 'linethickness', 'lspace',
|
||||
'mathbackground', 'mathcolor', 'mathvariant', 'mathvariant', 'maxsize',
|
||||
'minsize', 'other', 'rowalign', 'rowalign', 'rowalign', 'rowlines',
|
||||
'rowspacing', 'rowspan', 'rspace', 'scriptlevel', 'selection',
|
||||
'separator', 'stretchy', 'width', 'width', 'xlink:href', 'xlink:show',
|
||||
'xlink:type', 'xmlns', 'xmlns:xlink']
|
||||
|
||||
|
||||
svg_attributes = ['accent-height', 'accumulate', 'additive', 'alphabetic',
|
||||
'arabic-form', 'ascent', 'attributeName', 'attributeType',
|
||||
'baseProfile', 'bbox', 'begin', 'by', 'calcMode', 'cap-height',
|
||||
'class', 'color', 'color-rendering', 'content', 'cx', 'cy', 'd',
|
||||
'descent', 'display', 'dur', 'end', 'fill', 'fill-rule', 'font-family',
|
||||
'font-size', 'font-stretch', 'font-style', 'font-variant',
|
||||
'font-weight', 'from', 'fx', 'fy', 'g1', 'g2', 'glyph-name',
|
||||
'gradientUnits', 'hanging', 'height', 'horiz-adv-x', 'horiz-origin-x',
|
||||
'id', 'ideographic', 'k', 'keyPoints', 'keySplines', 'keyTimes',
|
||||
'lang', 'mathematical', 'max', 'min', 'name', 'offset', 'opacity',
|
||||
'origin', 'overline-position', 'overline-thickness', 'panose-1',
|
||||
'path', 'pathLength', 'points', 'preserveAspectRatio', 'r',
|
||||
'repeatCount', 'repeatDur', 'requiredExtensions', 'requiredFeatures',
|
||||
'restart', 'rotate', 'rx', 'ry', 'slope', 'stemh', 'stemv',
|
||||
'stop-color', 'stop-opacity', 'strikethrough-position',
|
||||
'strikethrough-thickness', 'stroke', 'stroke-dasharray',
|
||||
'stroke-dashoffset', 'stroke-linecap', 'stroke-linejoin',
|
||||
'stroke-miterlimit', 'stroke-width', 'systemLanguage', 'target',
|
||||
'text-anchor', 'to', 'transform', 'type', 'u1', 'u2',
|
||||
'underline-position', 'underline-thickness', 'unicode',
|
||||
'unicode-range', 'units-per-em', 'values', 'version', 'viewBox',
|
||||
'visibility', 'width', 'widths', 'x', 'x-height', 'x1', 'x2',
|
||||
'xlink:actuate', 'xlink:arcrole', 'xlink:href', 'xlink:role',
|
||||
'xlink:show', 'xlink:title', 'xlink:type', 'xml:base', 'xml:lang',
|
||||
'xml:space', 'xmlns', 'xmlns:xlink', 'y', 'y1', 'y2', 'zoomAndPan']
|
||||
|
||||
attr_val_is_uri = ['href', 'src', 'action', 'longdesc', 'xlink:href']
|
||||
|
||||
acceptable_css_properties = ['azimuth', 'background-color',
|
||||
'border-bottom-color', 'border-collapse', 'border-color',
|
||||
'border-left-color', 'border-right-color', 'border-top-color', 'clear',
|
||||
'color', 'cursor', 'direction', 'display', 'elevation', 'float', 'font',
|
||||
'font-family', 'font-size', 'font-style', 'font-variant', 'font-weight',
|
||||
'height', 'letter-spacing', 'line-height', 'overflow', 'pause',
|
||||
'pause-after', 'pause-before', 'pitch', 'pitch-range', 'richness',
|
||||
'speak', 'speak-header', 'speak-numeral', 'speak-punctuation',
|
||||
'speech-rate', 'stress', 'text-align', 'text-decoration', 'text-indent',
|
||||
'unicode-bidi', 'vertical-align', 'voice-family', 'volume',
|
||||
'white-space', 'width']
|
||||
|
||||
acceptable_css_keywords = ['auto', 'aqua', 'black', 'block', 'blue',
|
||||
'bold', 'both', 'bottom', 'brown', 'center', 'collapse', 'dashed',
|
||||
'dotted', 'fuchsia', 'gray', 'green', '!important', 'italic', 'left',
|
||||
'lime', 'maroon', 'medium', 'none', 'navy', 'normal', 'nowrap', 'olive',
|
||||
'pointer', 'purple', 'red', 'right', 'solid', 'silver', 'teal', 'top',
|
||||
'transparent', 'underline', 'white', 'yellow']
|
||||
|
||||
acceptable_svg_properties = [ 'fill', 'fill-opacity', 'fill-rule',
|
||||
'stroke', 'stroke-width', 'stroke-linecap', 'stroke-linejoin',
|
||||
'stroke-opacity']
|
||||
|
||||
acceptable_protocols = [ 'ed2k', 'ftp', 'http', 'https', 'irc',
|
||||
'mailto', 'news', 'gopher', 'nntp', 'telnet', 'webcal',
|
||||
'xmpp', 'callto', 'feed', 'urn', 'aim', 'rsync', 'tag',
|
||||
'ssh', 'sftp', 'rtsp', 'afs' ]
|
||||
|
||||
ALLOWED_ELEMENTS = acceptable_elements + mathml_elements + svg_elements unless defined?(ALLOWED_ELEMENTS)
|
||||
ALLOWED_ATTRIBUTES = acceptable_attributes + mathml_attributes + svg_attributes unless defined?(ALLOWED_ATTRIBUTES)
|
||||
ALLOWED_CSS_PROPERTIES = acceptable_css_properties unless defined?(ALLOWED_CSS_PROPERTIES)
|
||||
ALLOWED_CSS_KEYWORDS = acceptable_css_keywords unless defined?(ALLOWED_CSS_KEYWORDS)
|
||||
ALLOWED_SVG_PROPERTIES = acceptable_svg_properties unless defined?(ALLOWED_SVG_PROPERTIES)
|
||||
ALLOWED_PROTOCOLS = acceptable_protocols unless defined?(ALLOWED_PROTOCOLS)
|
||||
ATTR_VAL_IS_URI = attr_val_is_uri unless defined?(ATTR_VAL_IS_URI)
|
||||
|
||||
# Sanitize the +html+, escaping all elements not in ALLOWED_ELEMENTS, and stripping out all
|
||||
# attributes not in ALLOWED_ATTRIBUTES. Style attributes are parsed, and a restricted set,
|
||||
# specified by ALLOWED_CSS_PROPERTIES and ALLOWED_CSS_KEYWORDS, are allowed through.
|
||||
# attributes in ATTR_VAL_IS_URI are scanned, and only URI schemes specified in
|
||||
# ALLOWED_PROTOCOLS are allowed.
|
||||
# You can adjust what gets sanitized, by defining these constant arrays before this Module is loaded.
|
||||
#
|
||||
# sanitize_html('<script> do_nasty_stuff() </script>')
|
||||
# => <script> do_nasty_stuff() </script>
|
||||
# sanitize_html('<a href="javascript: sucker();">Click here for $100</a>')
|
||||
# => <a>Click here for $100</a>
|
||||
def sanitize_html(html)
|
||||
if html.index("<")
|
||||
tokenizer = HTML::Tokenizer.new(html)
|
||||
new_text = ""
|
||||
|
||||
while token = tokenizer.next
|
||||
node = XHTML::Node.parse(nil, 0, 0, token, false)
|
||||
new_text << case node.tag?
|
||||
when true
|
||||
if ALLOWED_ELEMENTS.include?(node.name)
|
||||
if node.closing != :close
|
||||
node.attributes.delete_if { |attr,v| !ALLOWED_ATTRIBUTES.include?(attr) }
|
||||
ATTR_VAL_IS_URI.each do |attr|
|
||||
val_unescaped = CGI.unescapeHTML(node.attributes[attr].to_s).gsub(/[\000-\040\177-\240]+/,'').downcase
|
||||
if val_unescaped =~ /^[a-z0-9][-+.a-z0-9]*:/ and !ALLOWED_PROTOCOLS.include?(val_unescaped.split(':')[0])
|
||||
node.attributes.delete attr
|
||||
end
|
||||
end
|
||||
if node.attributes['style']
|
||||
node.attributes['style'] = sanitize_css(node.attributes['style'])
|
||||
end
|
||||
end
|
||||
node.to_s
|
||||
else
|
||||
node.to_s.gsub(/</, "<")
|
||||
end
|
||||
else
|
||||
node.to_s.gsub(/</, "<")
|
||||
end
|
||||
end
|
||||
|
||||
html = new_text
|
||||
end
|
||||
html
|
||||
end
|
||||
|
||||
def sanitize_css(style)
|
||||
# disallow urls
|
||||
style = style.to_s.gsub(/url\s*\(\s*[^\s)]+?\s*\)\s*/, ' ')
|
||||
|
||||
# gauntlet
|
||||
if style !~ /^([:,;#%.\sa-zA-Z0-9!]|\w-\w|\'[\s\w]+\'|\"[\s\w]+\"|\([\d,\s]+\))*$/
|
||||
style = ''
|
||||
return style
|
||||
end
|
||||
if style !~ /^(\s*[-\w]+\s*:\s*[^:;]*(;|$))*$/
|
||||
style = ''
|
||||
return style
|
||||
end
|
||||
|
||||
clean = []
|
||||
style.scan(/([-\w]+)\s*:\s*([^:;]*)/) do |prop,val|
|
||||
if ALLOWED_CSS_PROPERTIES.include?(prop.downcase)
|
||||
clean << prop + ': ' + val + ';'
|
||||
elsif ['background','border','margin','padding'].include?(prop.split('-')[0].downcase)
|
||||
goodval = true
|
||||
val.split().each do |keyword|
|
||||
if !ALLOWED_CSS_KEYWORDS.include?(keyword) and
|
||||
keyword !~ /^(#[0-9a-f]+|rgb\(\d+%?,\d*%?,?\d*%?\)?|\d{0,2}\.?\d{0,2}(cm|em|ex|in|mm|pc|pt|px|%|,|\))?)$/
|
||||
goodval = false
|
||||
end
|
||||
end
|
||||
if goodval
|
||||
clean << prop + ': ' + val + ';'
|
||||
end
|
||||
elsif ALLOWED_SVG_PROPERTIES.include?(prop.downcase)
|
||||
clean << prop + ': ' + val + ';'
|
||||
end
|
||||
end
|
||||
|
||||
style = clean.join(' ')
|
||||
end
|
||||
end
|
||||
187
test/unit/sanitize_test.rb
Normal file
187
test/unit/sanitize_test.rb
Normal file
|
|
@ -0,0 +1,187 @@
|
|||
#!/usr/bin/env ruby
|
||||
|
||||
require File.expand_path(File.join(File.dirname(__FILE__), '/../test_helper'))
|
||||
require 'sanitize'
|
||||
|
||||
class SanitizeTest < Test::Unit::TestCase
|
||||
include Sanitize
|
||||
|
||||
def setup
|
||||
|
||||
end
|
||||
|
||||
Sanitize::ALLOWED_ELEMENTS.each do |tag_name|
|
||||
define_method "test_should_allow_#{tag_name}_tag" do
|
||||
assert_equal "<#{tag_name} title=\"1\">foo <bad>bar</bad> baz</#{tag_name}>",
|
||||
sanitize_html("<#{tag_name} title='1'>foo <bad>bar</bad> baz</#{tag_name}>")
|
||||
end
|
||||
end
|
||||
|
||||
Sanitize::ALLOWED_ELEMENTS.each do |tag_name|
|
||||
define_method "test_should_forbid_#{tag_name.upcase}_tag" do
|
||||
assert_equal "<#{tag_name.upcase} title=\"1\">foo <bad>bar</bad> baz</#{tag_name.upcase}>",
|
||||
sanitize_html("<#{tag_name.upcase} title='1'>foo <bad>bar</bad> baz</#{tag_name.upcase}>")
|
||||
end
|
||||
end
|
||||
|
||||
Sanitize::ALLOWED_ATTRIBUTES.each do |attribute_name|
|
||||
if attribute_name != 'style'
|
||||
define_method "test_should_allow_#{attribute_name}_attribute" do
|
||||
assert_equal "<p #{attribute_name}=\"foo\">foo <bad>bar</bad> baz</p>",
|
||||
sanitize_html("<p #{attribute_name}='foo'>foo <bad>bar</bad> baz</p>")
|
||||
end
|
||||
end
|
||||
end
|
||||
|
||||
Sanitize::ALLOWED_ATTRIBUTES.each do |attribute_name|
|
||||
define_method "test_should_forbid_#{attribute_name.upcase}_attribute" do
|
||||
assert_equal "<p>foo <bad>bar</bad> baz</p>",
|
||||
sanitize_html("<p #{attribute_name.upcase}='display: none;'>foo <bad>bar</bad> baz</p>")
|
||||
end
|
||||
end
|
||||
|
||||
Sanitize::ALLOWED_PROTOCOLS.each do |protocol|
|
||||
define_method "test_should_allow_#{protocol}_uris" do
|
||||
assert_equal "<a href=\"#{protocol}\">foo</a>",
|
||||
sanitize_html(%(<a href="#{protocol}">foo</a>))
|
||||
end
|
||||
end
|
||||
|
||||
Sanitize::ALLOWED_PROTOCOLS.each do |protocol|
|
||||
define_method "test_should_allow_uppercase_#{protocol}_uris" do
|
||||
assert_equal "<a href=\"#{protocol.upcase}\">foo</a>",
|
||||
sanitize_html(%(<a href="#{protocol.upcase}">foo</a>))
|
||||
end
|
||||
end
|
||||
|
||||
def test_should_allow_anchors
|
||||
assert_equal "<a href=\"foo\"><script>baz</script></a>",
|
||||
sanitize_html("<a href='foo' onclick='bar'><script>baz</script></a>")
|
||||
end
|
||||
|
||||
# RFC 3986, sec 4.2
|
||||
def test_allow_colons_in_path_component
|
||||
assert_equal "<a href=\"./this:that\">foo</a>",
|
||||
sanitize_html("<a href=\"./this:that\">foo</a>")
|
||||
end
|
||||
|
||||
%w(src width height alt).each do |img_attr|
|
||||
define_method "test_should_allow_image_#{img_attr}_attribute" do
|
||||
assert_equal "<img #{img_attr}=\"foo\" />",
|
||||
sanitize_html("<img #{img_attr}='foo' onclick='bar' />")
|
||||
end
|
||||
end
|
||||
|
||||
def test_should_handle_non_html
|
||||
assert_equal 'abc', sanitize_html("abc")
|
||||
end
|
||||
|
||||
def test_should_handle_blank_text
|
||||
assert_equal '', sanitize_html('')
|
||||
end
|
||||
|
||||
[%w(img src), %w(a href)].each do |(tag, attr)|
|
||||
define_method "test_should_strip_#{attr}_attribute_in_#{tag}_with_bad_protocols" do
|
||||
assert_equal %(<#{tag} title="1">boo</#{tag}>), sanitize_html(%(<#{tag} #{attr}="javascript:XSS" title="1">boo</#{tag}>))
|
||||
end
|
||||
end
|
||||
|
||||
[%w(img src), %w(a href)].each do |(tag, attr)|
|
||||
define_method "test_should_strip_#{attr}_attribute_in_#{tag}_with_bad_protocols_and_whitespace" do
|
||||
assert_equal %(<#{tag} title="1">boo</#{tag}>), sanitize_html(%(<#{tag} #{attr}=" javascript:XSS" title="1">boo</#{tag}>))
|
||||
end
|
||||
end
|
||||
|
||||
[%(<img src="javascript:alert('XSS');" />),
|
||||
%(<img src=javascript:alert('XSS') />),
|
||||
%(<img src="JaVaScRiPt:alert('XSS')" />),
|
||||
%(<img src='javascript:alert("XSS")' />),
|
||||
%(<img src='javascript:alert(String.fromCharCode(88,83,83))' />),
|
||||
%(<img src='javascript:alert('XSS')' />),
|
||||
%(<img src='javascript:alert('XSS')' />),
|
||||
%(<img src='javascript:alert('XSS')' />),
|
||||
%(<img src="jav\tascript:alert('XSS');" />),
|
||||
%(<img src="jav	ascript:alert('XSS');" />),
|
||||
%(<img src="jav
ascript:alert('XSS');" />),
|
||||
%(<img src="jav
ascript:alert('XSS');" />),
|
||||
%(<img src="  javascript:alert('XSS');" />),
|
||||
%(<img src=" javascript:alert('XSS');" />),
|
||||
%(<img src=" javascript:alert('XSS');" />)].each_with_index do |img_hack, i|
|
||||
define_method "test_should_not_fall_for_xss_image_hack_#{i}" do
|
||||
assert_equal "<img />", sanitize_html(img_hack)
|
||||
end
|
||||
end
|
||||
|
||||
def test_should_sanitize_tag_broken_up_by_null
|
||||
assert_equal "<scr>alert(\"XSS\")</scr>", sanitize_html(%(<scr\0ipt>alert(\"XSS\")</scr\0ipt>))
|
||||
end
|
||||
|
||||
def test_should_sanitize_invalid_script_tag
|
||||
assert_equal "<script /></script>", sanitize_html(%(<script/XSS SRC="http://ha.ckers.org/xss.js"></script>))
|
||||
end
|
||||
|
||||
def test_should_sanitize_script_tag_with_multiple_open_brackets
|
||||
assert_equal "<<script>alert(\"XSS\");//<</script>", sanitize_html(%(<<script>alert("XSS");//<</script>))
|
||||
assert_equal %(<iframe src="http:" /><), sanitize_html(%(<iframe src=http://ha.ckers.org/scriptlet.html\n<))
|
||||
end
|
||||
|
||||
def test_should_sanitize_unclosed_script
|
||||
assert_equal "<script src=\"http:\" /><b>", sanitize_html(%(<script src=http://ha.ckers.org/xss.js?<b>))
|
||||
end
|
||||
|
||||
def test_should_sanitize_half_open_scripts
|
||||
assert_equal "<img>", sanitize_html(%(<img src="javascript:alert('XSS')"))
|
||||
end
|
||||
|
||||
def test_should_not_fall_for_ridiculous_hack
|
||||
img_hack = %(<img\nsrc\n=\n"\nj\na\nv\na\ns\nc\nr\ni\np\nt\n:\na\nl\ne\nr\nt\n(\n'\nX\nS\nS\n'\n)\n"\n />)
|
||||
assert_equal "<img />", sanitize_html(img_hack)
|
||||
end
|
||||
|
||||
def test_platypus
|
||||
assert_equal %(<a href=\"http://www.ragingplatypus.com/\" style=\"display: block; width: 100%; height: 100%; background-color: black; background-image: ; background-x: center; background-y: center;\">never trust your upstream platypus</a>),
|
||||
sanitize_html(%(<a href="http://www.ragingplatypus.com/" style="display:block; position:absolute; left:0; top:0; width:100%; height:100%; z-index:1; background-color:black; background-image:url(http://www.ragingplatypus.com/i/cam-full.jpg); background-x:center; background-y:center; background-repeat:repeat;">never trust your upstream platypus</a>))
|
||||
end
|
||||
|
||||
def test_xul
|
||||
assert_equal %(<p style="">fubar</p>),
|
||||
sanitize_html(%(<p style="-moz-binding:url('http://ha.ckers.org/xssmoz.xml#xss')">fubar</p>))
|
||||
end
|
||||
|
||||
def test_input_image
|
||||
assert_equal %(<input type="image" />),
|
||||
sanitize_html(%(<input type="image" src="javascript:alert('XSS');" />))
|
||||
end
|
||||
|
||||
def test_non_alpha_non_digit
|
||||
assert_equal "<script /></script>",
|
||||
sanitize_html(%(<script/XSS src="http://ha.ckers.org/xss.js"></script>))
|
||||
assert_equal "<a>foo</a>",
|
||||
sanitize_html('<a onclick!#$%&()*~+-_.,:;?@[/|\]^`=alert("XSS")>foo</a>')
|
||||
assert_equal "<img />",
|
||||
sanitize_html('<img/src="http://ha.ckers.org/xss.js"/>')
|
||||
end
|
||||
|
||||
def test_img_dynsrc_lowsrc
|
||||
assert_equal "<img />",
|
||||
sanitize_html(%(<img dynsrc="javascript:alert('XSS')" />))
|
||||
assert_equal "<img />",
|
||||
sanitize_html(%(<img lowsrc="javascript:alert('XSS')" />))
|
||||
end
|
||||
|
||||
def test_div_background_image_unicode_encoded
|
||||
assert_equal '<div style="">foo</div>',
|
||||
sanitize_html(%(<div style="background-image:\0075\0072\006C\0028'\006a\0061\0076\0061\0073\0063\0072\0069\0070\0074\003a\0061\006c\0065\0072\0074\0028.1027\0058.1053\0053\0027\0029'\0029">foo</div>))
|
||||
end
|
||||
|
||||
def test_div_expression
|
||||
assert_equal '<div style="">foo</div>',
|
||||
sanitize_html(%(<div style="width: expression(alert('XSS'));">foo</div>))
|
||||
end
|
||||
|
||||
def test_img_vbscript
|
||||
assert_equal '<img />',
|
||||
sanitize_html(%(<img src='vbscript:msgbox("XSS")' />))
|
||||
end
|
||||
|
||||
end
|
||||
Loading…
Reference in a new issue