One of the things that I’ve had in mind when I started coding this blog in Rails was to eventually support Gravatars otherwise known as Globally Recognized Avatars.

Before rolling out this feature, comments had a little astronaut next to the speech bubble for each and every individual comment. If you have registered your email and uploaded a photo with the Gravatar service, it will no longer display the astronaut icon and it will load the registered image. If you haven’t registered, your comment gets a default kanji image.

Making this change in Rails was actually pretty trivial especially since Michael Mayo posted a very nice tutorial not long ago on his blog.

I did make some modifications from the code that he posted.

One of the more prominent changes that I made was to split out the image creation from the just generating the URL.

For example, I have this first method in my application_helper.rb file:

def gravatar_url_for(email, options = {})
      url_for({ :gravatar_id => Digest.MD5.hexdigest(email.downcase), :host => 'www.gravatar.com',
                   :protocol => 'http://', :only_path => false, :controller => 'avatar.php',
                   :default => 'http://eddorre.com/images/visitor.png',
                   :rating => 'G'}.merge(options))
end

I convert the email address to lowercase letters with the downcase method because an MD5 of noemail@eddorre.com and NOEMAIL@eddorre.com are actually two different things. This way, there can be no error. One of the other settings that I’m passing in is a “default” flag. If you haven’t registered with the Gravatar service, I’ll just use the astronaut image that I have and finally I don’t want goatse photos or worse showing up on my blog so I make the rating a mandatory “G”.

Notice that the above method doesn’t actually generate an image tag, it will only generate a URL.

For that, I have a second helper method defined simply as:

def gravatar_image(email, options = {})
      image_tag(gravatar_url_for(email, options), :alt => "Author Image")
end

This is the code that actually creates the Gravatar image.

Now in my view code, I can do the following (where @comment.email represents a variable with the user’s email address):

<%= gravatar_image(@comment.email, { :size => 40 }) %>

And it will display the image correctly. I should note that Michael’s example lists a size in height and width and you’ll notice that I’m passing the size as just an integer. I believe that the height and width options have been deprecated in favor of the more succinct size option.