How to redirect to a 404 in Rails?

Question

I'd like to 'fake' a 404 page in Rails. In PHP, I would just send a header with the error code as such:

header("HTTP/1.0 404 Not Found"); 

How is that done with Rails?

Answer 1

Don't render 404 yourself, there's no reason to; Rails has this functionality built in already. If you want to show a 404 page, create a render_404 method (or not_found as I called it) in ApplicationController like this:

def not_found   raise ActionController::RoutingError.new('Not Found') end 

Rails also handles AbstractController::ActionNotFound, and ActiveRecord::RecordNotFound the same way.

This does two things better:

1) It uses Rails' built in rescue_from handler to render the 404 page, and 2) it interrupts the execution of your code, letting you do nice things like:

  user = User.find_by_email(params[:email]) or not_found   user.do_something! 

without having to write ugly conditional statements.

As a bonus, it's also super easy to handle in tests. For example, in an rspec integration test:

# RSpec 1  lambda {   visit '/something/you/want/to/404' }.should raise_error(ActionController::RoutingError)  # RSpec 2+  expect {   get '/something/you/want/to/404' }.to raise_error(ActionController::RoutingError) 

And minitest:

assert_raises(ActionController::RoutingError) do    get '/something/you/want/to/404' end 

OR refer more info from Rails render 404 not found from a controller action