Top Level Namespace

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Modules: Active

Instance Method Summary collapse

Instance Method Details

#sanitize(html, okTags = 'a href, b, br, i, p') ⇒ Object

$Id: sanitize.rb 3 2005-04-05 12:51:14Z dwight $

Copyright © 2005 Dwight Shih A derived work of the Perl version: Copyright © 2002 Brad Choate, bradchoate.com

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.



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# File 'lib/services/sanitize.rb', line 35

def sanitize( html, okTags='a href, b, br, i, p' )
  # no closing tag necessary for these
  soloTags = ["br","hr"]

  # Build hash of allowed tags with allowed attributes
  tags = okTags.downcase().split(',').collect!{ |s| s.split(' ') }
  allowed = Hash.new
  tags.each do |s|
    key = s.shift
    allowed[key] = s
  end

  # Analyze all <> elements
  stack = Array.new
  result = html.gsub( /(<.*?>)/m ) do | element |
    if element =~ /\A<\/(\w+)/ then
      # </tag>
      tag = $1.downcase
      if allowed.include?(tag) && stack.include?(tag) then
        # If allowed and on the stack
        # Then pop down the stack
        top = stack.pop
        out = "</#{top}>"
        until top == tag do
          top = stack.pop
          out << "</#{top}>"
        end
        out
      end
    elsif element =~ /\A<(\w+)\s*\/>/
      # <tag />
      tag = $1.downcase
      if allowed.include?(tag) then
        "<#{tag} />"
      end
    elsif element =~ /\A<(\w+)/ then
      # <tag ...>
      tag = $1.downcase
      if allowed.include?(tag) then
        if ! soloTags.include?(tag) then
          stack.push(tag)
        end
        if allowed[tag].length == 0 then
          # no allowed attributes
          "<#{tag}>"
        else
          # allowed attributes?
          out = "<#{tag}"
          while ( $' =~ /(\w+)=("[^"]+")/ )
            attr = $1.downcase
            valu = $2
            if allowed[tag].include?(attr) then
              out << " #{attr}=#{valu}"
            end
          end
          out << ">"
        end
      end
    end
  end
  
  # eat up unmatched leading >
  while result.sub!(/\A([^<]*)>/m) { $1 } do end
  
  # eat up unmatched trailing <
  while result.sub!(/<([^>]*)\Z/m) { $1 } do end
  
  # clean up the stack
  if stack.length > 0 then
    result << "</#{stack.reverse.join('></')}>"
  end

  result
end