Rails Exception Handling

An example of what i do in my own code:

def create  @letter = Letter.new(params[:id])  begin    @letter.do_something_that_could_throw_an_exception    flash[:notice] = I18n.translate('letter.success_create')  rescue => e    logger.error "letter_controller::create => exception #{e.class.name} : #{e.message}"    flash[:error] = "#{I18n.translate('letter.letter_create_failed')}<br/>Detailed error: #{e.message}"    ExceptionNotifier.deliver_exception_notification(e, self, request)    # redirect somewhere sensible?  endend

end

Does that help?

Exceptions that happen as a part of saving/creating a model

I use the ActiveRecord callbacks after_validation, after_validation_on_create, and before_save (depending on the circumstance), to obtain any extra data and verify that everything is ready to be saved. Then, if any problems, I store the exception in errors[:base] using add_to_base. That way the view will display the error msg in the same way it displays any other validation errors.

Remember that if your before_save method returns false, the save will fail.

Exceptions for other model methods

All the usual methods are available:

1. Raise a specific exception that the controller will catch. The exception can include an error number that the view translates to an error msg. Or the model can export an error_num to error_msg hash
2. Return an error code as a return parameter of the method. Eg if you want to also use the Flash to give a positive msg when things work, you can return a msg_code. Then have negative msg codes for errors and positive codes for different types of success.
3. Establish an @error (or whatever) instance variable to be checked by the caller.

begin       Some coderescue =>e       @error= e.message       Exception Handlingend

in views

<%= @error %>