[UPDATE 2007-02-07] Changed scrub to return self [/UPDATE]

Using Hpricot to Scrub HTML – The remix

So I wanted to bring the HTML Scrubber into my Hpricot tweaks to tidy it up a bit and this is what I ended up with.

Now you can use the following to remove all tags from an HTML snippet

doc = Hpricot(open('http://slashdot.org/').read)
doc.scrub

Strip all hrefs, leaving the text inside in tact
(doc/:a).strip
Scrub the snippet based on a config hash

doc.scrub(hash)

hpricot_scrub.rb

require 'hpricot'

module Hpricot

  class Elements

    def strip

      each { |x| x.strip }

    end
def strip_attributes(safe=[])
each { |x| x.strip_attributes(safe) }
end
end
class Elem
def remove
parent.children.delete(self)
end
def strip
children.each { |x| x.strip unless x.class == Hpricot::Text }
if strip_removes?
remove
else
parent.replace_child self, Hpricot.make(inner_html) unless parent.nil?
end
end

def strip_attributes(safe=[])
attributes.each {|atr|
remove_attribute(atr0) unless safe.include?(atr0)
} unless attributes.nil?
end

def strip_removes?

	
I’m sure there are others that shuould be ripped instead of stripped

      attributes && attributes[‘type’] =~ /script|css/

    end

  end

class Doc
def scrub(config={})
config = {
:nuke_tags => [],
:allow_tags => [],
:allow_attributes => []
}.merge(config)

config[:nuke_tags].each { |tag| (self/tag).remove }
config[:allow_tags].each { |tag|
(self/tag).strip_attributes(config[:allow_attributes])
}
children.reverse.each {|e|
e.strip unless e.class == Hpricot::Text ||
config[:allow_tags].include?(e.name)
}
self
end
end
end

Sample config in YAML

---
  :allow_tags: # let these tags stay, but will strip attributes
    - 'b'
    - 'blockquote'
    - 'br'
    - 'div'
    - 'h1'
    - 'h2'
    - 'h3'
    - 'h4'
    - 'h5'
    - 'h6'
    - 'hr'
    - 'i'
    - 'em'
    - 'img'
    - 'li'
    - 'ol'
    - 'p'
    - 'pre'
    - 'small'
    - 'span'
    - 'span'
    - 'strike'
    - 'strong'
    - 'sub'
    - 'sup'
    - 'table'
    - 'tbody'
    - 'td'
    - 'tfoot'
    - 'thead'
    - 'tr'
    - 'u'
    - 'ul'

:nuke_tags: # completely removes everything between open and close tag
- ‘form’
- ‘script’

:allow_attributes: # let these attributes stay, strip all others
- ‘src’
- ‘font’
- ‘alt’
- ‘style’
- ‘align’

The source with sample data/test, run the test with

ruby test