Rails controller - handle 404 and respond with dynamic HTML error page regardless of request format

Question

Suppose I have the following logic in my ApplicationController:

rescue_from ActionController::RoutingError, :with => :handle_routing_error

def handle_routing_error(exception)
 logger.info { "handling routing error: #{exception.message}" }
 render template: 'errors/error_404', status: 404
end

This renders my custom (and dynamic) 404 error page for all requests in the HTML format.

However, when someone provides a URL indicating a non-HTML format, e.g. mysite.com/missingfile.png this throws a 500 error becauses I don't have a error_404.png template:

Missing template errors/error_404, public_site/error_404, application/error_404 with {:locale=>[:en], :formats=>[:png], :handlers=>[:erb, :builder, :coffee, :rabl, :haml]}. Searched in:

How can I override the request format and always show my dynamic HTML 404 page? I want it to work like twitter: https://twitter.com/missingfile.png.

A key point is that this is a dynamic 404 page, so the usual public/404.html route does not work for me.

Thanks!

Also just a heads up: I do not want to render: none with status 404 for non-HTML formats, nor do I want to return a 406 error, which are both options on some blogs I have seen that deal with this topic. — kgx
– kgx, Commented Feb 19, 2013 at 6:11
What is your Rails version? I doubt you can still catch RoutingError from rescue_from as RoutingError is in middleware since 3.2.x and can't be caught at ApplicationController — Billy Chan
– Billy Chan, Commented Feb 19, 2013 at 8:12
Billy thanks, good point. I am using Rails 3.2.12. This rescue clause is only being used when I manually throw 404 exceptions from controllers. I just remembered that I have a catch all mapping: match '*not_found', to: 'errors#error_404. — kgx
– kgx, Commented Feb 19, 2013 at 17:30
Anyways, I got the behavior that I want working. I will update my question with the solution when I have a chance. — kgx
– kgx, Commented Feb 19, 2013 at 17:31
Yes, the error can be caught at specific controller level but not ApplicationController. Here is a good ref: coderwall.com/p/w3ghqq — Billy Chan
– Billy Chan, Commented Feb 19, 2013 at 17:39

MilesStanfield · Accepted Answer · 2015-08-08 15:08:49Z

1

Do this ...

#config/routes
get "*unmatched_route", :to => "application#error_page"


#controllers/application_controller
def error_page
  render :template => 'errors/error_404', status: 404
end

answered Aug 8, 2015 at 15:08

MilesStanfield

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1 Comment

Rajan Verma - Aarvy Over a year ago

it is reporting every page a 404

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