26

I've got the following error:

ActionController::RoutingError (No route matches [GET] "/images/favicon.ico")

I want to show error404 page for links that are not existing.

How can I achieve that?

Andrey Deineko
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Anna
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4 Answers4

62

In application_controller.rb add the following: 

  # You want to get exceptions in development, but not in production.
  unless Rails.application.config.consider_all_requests_local
    rescue_from ActionController::RoutingError, with: -> { render_404  }
  end

  def render_404
    respond_to do |format|
      format.html { render template: 'errors/not_found', status: 404 }
      format.all { render nothing: true, status: 404 }
    end
  end

I usually also rescue following exceptions, but that's up to you:

rescue_from ActionController::UnknownController, with: -> { render_404  }
rescue_from ActiveRecord::RecordNotFound,        with: -> { render_404  }

Create the errors controller:

class ErrorsController < ApplicationController
  def error_404
    render 'errors/not_found'
  end
end

Then in routes.rb

  unless Rails.application.config.consider_all_requests_local
    # having created corresponding controller and action
    get '*path', to: 'errors#error_404', via: :all
  end

And the last thing is to create not_found.html.haml (or whatever template engine you use) under /views/errors/:

  %span 404
  %br
  Page Not Found
FloatingRock
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Andrey Deineko
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    This doesn't work in Rails 4.2.5. I'm guessing that's because the exception is raised by ActionDispatch before any controller code is run. – depquid Feb 03 '16 at 18:19
  • @depquid I wrote it in the times of Rails 4.0.x, but have just tested it with Rails 4.2.5 - I suppose you did not add route and did not create the `errors_controller.rb` :) If that is the case - please be sure to retract the downvote, unless you have more reasons to leave it – Andrey Deineko Feb 03 '16 at 18:58
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    Sorry, I didn't set up the route correctly. But why have, `rescue_from ActionController::RoutingError, with: -> { render_404 }` if you're routing directly to the action? – depquid Feb 03 '16 at 22:11
  • If you need to catch this before any Controller code is run (i.e. on the Routes level), see @misu's answer below for adding `match '*path' => 'errors#error_404', via: :all`. – skplunkerin May 17 '18 at 17:44
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    How can you get a `ActionController::RoutingError` when you have a path that matches everything (`get '*path', to: 'errors#error_404', via: :all`) ? – B Seven Apr 19 '20 at 02:59
10

@Andrey Deineko, your solution seems to work only for the RoutingErrors raised manually inside a conrtoller. If I try it with the url my_app/not_existing_path, I still get the standard error message.

I guess this is because the application doesn't even reach the controllers, since Rails raises the error before.

The trick that solved the problem for me was to add the following line at the end of the routes:

Rails.application.routes.draw do
  # existing paths
  match '*path' => 'errors#error_404', via: :all
end

to catch all not predefined requests.

Then in the ErrorsController you can use respond_to to serve html, json... requests:

class ErrorsController < ApplicationController
  def error_404
    @requested_path = request.path
    repond_to do |format|
      format.html
      format.json { render json: {routing_error: @requested_path} }
    end
  end
end
Community
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Misu
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  • could you explain `@requested_path = request.path` and its corresponding call `format.json { render json: {routing_error: @requested_path} }`? – Afolabi Olaoluwa Nov 04 '16 at 12:28
  • I've just used `@requested_path` in the template (error_404.html.haml). As for the json, if I'm sure I don't want a full page returned, for example by ajax, I can ask for json returned, and get the error message – Misu Nov 05 '16 at 07:04
  • @misu this works perfect, your trick of adding this in the `config/routes.rb` file was the key – skplunkerin May 17 '18 at 17:43
1

Copying favicon image in app/assets/images worked for me.

double-beep
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Anuja
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0

In Rails 7 (2023)

  1. config/routes.rb

    Rails.application.routes.draw do

    match '*path' => 'errors#error_404', via: :all

    end

  2. controllers/errors_controller.rb

    class ErrorsController < ApplicationController

    def error_404

     render template: 'pages/not_found', status: 404

    end

    end

  3. pages/not_found.html.erb

Error 404

Page not found

... but you are losing all active_storage images!!!

coopeu
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