Foreman » Smart Proxy

We use rescue blocks in actions like here

 post "/dns/" do
    fqdn  = params[:fqdn]
    value = params[:value]
    type  = params[:type]
    begin
      dns_setup({:fqdn => fqdn, :value => value, :type => type})
      @server.create
    rescue Proxy::DNS::Collision => e
      log_halt 409, e
    rescue Exception => e
      log_halt 400, e
    end
  end

Instead we should use error handler http://www.sinatrarb.com/intro.html#Error%20Handling at least for specific exceptions to be more DRY. We should add custom exceptions where needed.