Plugins - Secure Actions
Add to favoritesThis plugin lets you declare which actions you want to be accessed via https.
If you declare an action to be ssl_required, then if it is accessed without ssl, it is redirected to https://
Also, any links to these actions will automatically be https:// links.

I don't if this the right place to report this but I found a small bug in the plugin's code.
The bug arises when a http request is redirected to https with the 'ensureproperprotocol' method. Any params sent to with the http request are lost in the redirect to https.
This is an easy fix:
def ensureproperprotocol if !request.ssl? && USESSL && sslrequired? params[:protocol] = 'https://' redirect_to params return false end return true end