gistfile1.rb

# by Joel VanderWerf

require 'hpricot'

module Webby
class Renderer
 attr_reader :page
end

module Filters

# To use: add relpath to the end of the list of filters in the layout. It won't
# work in the content file itself.
class RelPath
 def initialize( str, mode, path )
   @str = str
   @mode = mode.downcase.to_sym
   dir = File.dirname(path)
   depth = 0
   while (parent = File.dirname(dir)) != dir
     dir = parent
     depth += 1
   end
   depth -= 1 # because of the 'content/' prefix
   @prefix = "../" * depth
 end

 def filter
   doc = @mode == :xml ? Hpricot.XML(@str) : Hpricot(@str)
   attr_rgxp = %r/\[@(\w+)\]$/o
   sub_rgxp = %r/\A\//o # <-- note this rgxp _consumes_ the "/"

   ::Webby.site.xpaths.each do |xpath|
     @attr_name = nil
     doc.search(xpath).each do |element|
       @attr_name ||= attr_rgxp.match(xpath)[1]
       a = element.get_attribute(@attr_name)
       element.set_attribute(@attr_name, a) if a.sub!(sub_rgxp, @prefix)
     end
   end

   doc.to_html
 end
end

register :relpath do |input, cursor|
 RelPath.new(input, cursor.page.extension, cursor.renderer.page.path).filter
end

end  # module Filters
end  # module Webby