Question

I am working on a RoR website and would like to handle server errors (400, 404, 500, etc.) individually. Also, since the website is dynamic I would like to handle the errors within the rails environment rather than at the server level.
An example of what I would like to do could be to present the user with optional material or a search bar when she bumps into a page or template that will not load or simply does not exist.

So, I did a bit of reading and I think that using the rescue_from exception handler is the way to go in my case. (Would be more than happy to hear if any of you have a different opinion).

I have a simple working prototype (see code below) up and running, however, I get an error when I include the following exception handler to the code:

rescue_from ActionController::MissingTemplate,          :with => :not_found #404

Now, I can’t see that I have a spelling error and I have seen this line in code posted on the web. However, when I include it I get the following routing error:

Routing Error No route matches "/errorhandle" with {:method=>:get}

I am working on rails 2.3.5, perhaps that has got something to do with it?

class ApplicationController < ActionController::Base

    helper :all # include all helpers, all the time

    protect_from_forgery #See ActionController::RequestForgeryProtection for details

    #ActiveRecord exceptions
    rescue_from ActiveRecord::RecordNotFound, :with => :not_found #400   

    #ActiveResource exceptions  
    rescue_from ActiveResource::ResourceNotFound, :with => :not_found #404

    #ActionView exceptions
    rescue_from ActionView::TemplateError, :with => :not_found #500

    #ActionController exceptions
    rescue_from ActionController::RoutingError, :with => :not_found #404   

    rescue_from ActionController::UnknownController, :with => :not_found #404 

    rescue_from ActionController::MethodNotAllowed, :with => :not_found #405   

    rescue_from ActionController::InvalidAuthenticityToken, :with => :not_found #405

    rescue_from ActionController::UnknownAction, :with => :not_found #501

    # This particular exception causes all the rest to fail.... why?
    # rescue_from ActionController::MissingTemplate, :with => :not_found #404
    
    protected
    def not_found
        render :text => "Error", :status => 404
    end

    # Scrub sensitive parameters from your log
    # filter_parameter_logging :password 
end

Answer 1

Take a quick look at these:
http://www.ruby-forum.com/topic/47898

http://henrik.nyh.se/2008/09/404-invalid-rails-format

In particular, a post in the first link:

You can’t use a regular ‘rescue’ keyword to rescue MissingTemplate
exception.

Use rescue_action instead, for example:

def rescue_action(exception)
  if ::ActionController::MissingTemplate === exception
     render :text => 'rescued'
  else
     super
  end
end

Kent.