Bells and whistles are always fun, so when whipping together this blog I wanted to try my hand at adding a few. First “nice-to-have” I went after was adding Gravitar to the comments. I did not really expect to much of a challenge but I had no idea it would be this straightforward.

Extend the string class a little.

# config/initializers/string_extensions.rb
class String

  def md5
    Digest::MD5.hexdigest(self)
  end

  def uri_encode
    URI.escape(self, Regexp.new("[^#{URI::PATTERN::UNRESERVED}]"))
  end

end

Add a few constants for cleanup.

# config/initializers/constants.rb
GRAVITAR_BASE_URL = 'http://www.gravatar.com/avatar.php'
GRAVITAR_DEFAULT_IMAGE = "http://#{HOST}/images/default_gravitar.gif" 
GRAVITAR_SIZE = 40

And of course add in your view helper.

# app/helpers/application_helper.rb
def gravitar_image_tag(email, html_options = {})
  image_tag gravitar_url(email), html_options
end

private
  def gravitar_url(email)
    return GRAVITAR_DEFAULT_IMAGE if email.nil?
    "#{GRAVITAR_BASE_URL}?gravatar_id=#{email.md5}&default=#{GRAVITAR_DEFAULT_IMAGE.uri_encode}&size=#{GRAVITAR_SIZE}" 
  end

That is it… done! Start calling it from your views.

gravitar_image_tag comment.email