How do I raise an exception in Rails so it behaves like other Rails exceptions?

You don't have to do anything special, it should just be working.

When I have a fresh rails app with this controller:

class FooController < ApplicationController  def index    raise "error"  endend

and go to http://127.0.0.1:3000/foo/

I am seeing the exception with a stack trace.

You might not see the whole stacktrace in the console log because Rails (since 2.3) filters lines from the stack trace that come from the framework itself.

See config/initializers/backtrace_silencers.rb in your Rails project

You can do it like this:

class UsersController < ApplicationController  ## Exception Handling  class NotActivated < StandardError  end  rescue_from NotActivated, :with => :not_activated  def not_activated(exception)    flash[:notice] = "This user is not activated."    Event.new_event "Exception: #{exception.message}", current_user, request.remote_ip    redirect_to "/"  end  def show      // Do something that fails..      raise NotActivated unless @user.is_activated?  endend

What you're doing here is creating a class "NotActivated" that will serve as Exception. Using raise, you can throw "NotActivated" as an Exception. rescue_from is the way of catching an Exception with a specified method (not_activated in this case). Quite a long example, but it should show you how it works.

Best wishes,
Fabian

If you need an easier way to do it, and don't want much fuss, a simple execution could be:

raise Exception.new('something bad happened!')

This will raise an exception, say e with e.message = something bad happened!

and then you can rescue it as you are rescuing all other exceptions in general.