If a request to my Sinatra app would return 404 just because of a trailing slash, redirect to the correct path.

sinatra trailing slash.rb

not_found do
    # redirect GET and HEAD requests to "/foo/" to "/foo"
    if (request.get? || request.head?) && request.path_info[-1] == "/"
        newpath = request.path_info.chop
        if Sinatra::Application.routes["GET"].find {|re,*other| newpath =~ re }
            redirect to(newpath)
        end
    end
    haml :x404
end