Implemented signup_url according to http://blog.gravatar.com/2009/08/…

…10/what-has-been-going-on-in-the-world-of-gravatar/.

lib/gravatar.rb

@@ -18,7 +18,7 @@
 class Gravatar
   API_METHODS = [
     :exists?, :addresses, :user_images, :save_data!, :save_image!, :save_url!, :use_image!, :use_user_image!,
-    :remove_image!, :delete_user_image!, :test, :image_url, :image_data
+    :remove_image!, :delete_user_image!, :test, :image_url, :image_data, :signup_url
   ]
   autoload :TestCase, File.expand_path('gravatar/test_case', File.dirname(__FILE__))
 
@@ -207,6 +207,15 @@ def image_url(options = {})
     "#{proto}://#{sub}.gravatar.com/avatar/#{email_hash}#{extension_for_image(options)}#{query_for_image(options)}"
   end
 
+  # Returns the URL for Gravatar's signup form, with the user's email pre-filled. Options include:
+  #
+  #   :locale                if non-nil, wil be used to prefix the URL. Example: :en
+  def signup_url(options = {})
+    locale_prefix = options[:locale] ? "#{options[:locale]}." : ''
+
+    "https://#{locale_prefix}gravatar.com/site/signup/#{CGI.escape(email)}"
+  end
+
   # Returns the image data for this user's gravatar image. This is the same as reading the data at #image_url. See
   # that method for more information.
   #

spec/lib/gravatar_spec.rb

@@ -173,5 +173,13 @@
       )
       combinations.should include(image_url(:ssl => true, :default => "identicon", :size => 80, :rating => :g))
     end
+
+    it "should return gravatar signup_url" do
+      signup_url.should == "https://gravatar.com/site/signup/gravatartest123%40gmail.com"
+    end
+
+    it "should return gravatar signup_url with locale" do
+      signup_url(:locale => :en).should == "https://en.gravatar.com/site/signup/gravatartest123%40gmail.com"      
+    end
   end
 end