GuessHTMLEncoding

GuessHTMLEncoding is a simple library to guess HTML encodings in Ruby 1.9. It considers HTTP headers and META tags.

Install

(sudo) gem install guess_html_encoding

Usage

GuessHTMLEncoding can guess the encoding of an HTML file based on the http-equiv content-type:

require 'rubygems'
require 'guess_html_encoding'

guess = GuessHtmlEncoding.guess(<<-HTML)
  <html>
    <head>
      <meta http-equiv="content-type" content="text/html; charset=LATIN1">
    </head>
    <body>
      <div>hi!</div>
    </body>
  </html>
HTML
guess.should == "ISO-8859-1"

You can also give it HTTP headers to guess from, which it will prefer, both as a string or as a hash:

guess = GuessHtmlEncoding.guess("<html><body><div>hi!</div></body></html>",
                                "Hello: world\nContent-Type: text/html; charset=LATIN1\nFoo: bar")
guess.should == "ISO-8859-1"

guess = GuessHtmlEncoding.guess("<html><body><div>hi!</div></body></html>",
                                {"Hello" => "world", "Content-Type" => "text/html; charset=LATIN1", "Foo" => "bar"})
guess.should == "ISO-8859-1"

It's likely that you want to force the encoding of the given HTML into the guessed encoding. This is easy to do:

data = "<html><head><meta http-equiv='content-type' content='text/html; charset=utf8;'></head><body><div>hi!♥</div></body></html>"
encoded = GuessHtmlEncoding.encode(data)
encoded.encoding.to_s.should == "UTF-8"

If an encoding cannot be guessed, or Ruby doesn't understand it, UTF-8 will be used and unknown characters will be ignored.