Nokogiri and Mechanize problem - ruby

Question

I am doing one the examples at the mechanize doc site and I want to parse the results using
nokogiri.
My problem is that when the following line gets executed:
doc = Nokogiri::HTML(search_results, 'UTF-8' )
the following error occurs:
C:/Ruby192/lib/ruby/gems/1.9.1/gems/nokogiri-1.4.4.1-x86-mingw32/lib/nokogiri/html/document.rb:71:in `parse': undefined method `name' for "UTF-8":String (NoMethodError)
from C:/Ruby192/lib/ruby/gems/1.9.1/gems/nokogiri-1.4.4.1-x86-mingw32/lib/nokogiri/html.rb:13:in `HTML'
from mechanize_test.rb:16:in `<main>'
I have installed ruby 1.9 on a windows vista machine
The results returned by mechanize are non-latin (utf8)
The code sample follows.
# encoding: UTF-8
require 'rubygems'
require 'mechanize'
require 'nokogiri'
agent = Mechanize.new
agent.user_agent_alias = 'Mac Safari'
page = agent.get("http://www.google.com/")
search_form = page.form_with(:name => "f")
search_form.field_with(:name => "q").value = "invitations"
search_results = agent.submit(search_form)
puts search_results.body
doc = Nokogiri::HTML(search_results, 'UTF-8')

Answer 1

#Douglas Drouillard
Thanx for looking into this. I found out I made a mistake. The call to nokogiri should have been:
doc = Nokogiri::HTML(search_results.body, 'UTF-8')
Note that search_results is different that search_results.body.
Search_results contains info coming right out of mechanize instantiation
while search_resuls.body contains html utf8 info that nokogiri can parse with no problem.

Answer 2

This appears to be issue with what Nokogiri expects as parameters to the parse method that is being called. The first issue I see, is that you are passing in the encoding option in the wrong parameter slot,
A parsing example from Nokogiri project page that specifies encoding
Nokogiri.XML('<foo><bar /><foo>', nil, 'EUC-JP')
Notice the encoding is the third parameter, not the second. But that still does not fully explain the behavior you are seeing, as the encoding should simply be ignored.
Per the Nokogiri documentation a call to Nokogiri::HTML() is a convenience method for the parse method.
Code for Nokogiri::HTML::parse
def parse thing, url = nil, encoding = nil, options = XML::ParseOptions::DEFAULT_HTML, &block
document.parse(thing, url, encoding, options, &block)
end
The source for the Nokogiri::HTML::Document parse method is a bit long, but here is the relevant part though:
string_or_io.respond_to?(:encoding)
unless string_or_io.encoding.name == "ASCII-8BIT"
encoding ||= string_or_io.encoding.name
end
end
Notice string_or_io.encoding.name, this matches the error your saw, undefined method 'name' for "UTF-8":String (NoMethodError).
Does your search_results object has an attribute with a key value pair of {:encoding => 'UTF-8'}? It appears Nokogiri is looking for the encoding to store an object that then has a name attribute of 'UTF-8'.