Getting Format in Mailer View in Rails

In my Rails app, I use a method in my Mailer views for creating a link that takes a format param based on whether it's in html or text format.

mailer_link_to( url, link_text, format )

Depending on the format, it either creates an anchor <a> tag for html or just shows the url for text.

So for each Mailer method, I have two views:

myemail.html.erb
myemail.text.erb

In myemail.html.erb, I use mailer_link_to( "http://ntwrkapp.com", "ntwrk", "html" ).

In myemail.text.erb I use mailer_link_to( "http://ntwrkapp.com", "ntwrk", "text" ).

What I'm wondering is if I can determine what the format is so I'm not having to duplicate myself so much and specify "html" or "text" each time.

If I was in a normal view/controller, I would do something like request.format but the request object isn't available in the Mailer views.

Thanks!