FourOFour

A super simple Rack middleware to capture 404 responses and change the response for any other logic.

With FourOFour you will be able to handle your 404 responses and change how your application behave dynamically and with the 'right' way: using a class for a delegation, separating all the concerns. Routes and logic should have their own space.

Installation

Add this line to your application's Gemfile:

gem 'four_o_four'

And then execute:

$ bundle

Or install it yourself as:

$ gem install four_o_four

Usage

After install you need to add this gem as a Rack application within your application. On rails can be done like this:

module YourAwesomeApp
  class Application < Rails::Application
    # .... extra configuration
    config.middleware.insert_before ActionDispatch::RemoteIp, FourOFour
  end
end

This will activate every 404 and will take control of the 404 page displaying a generic page saying

Default FourOuFour Application

Please configure your middleware to pass a delegation class

The interesting part comes with the configuration. You can pass a second parameter to the configuration...

module YourAwesomeApp
  class Application < Rails::Application
    # .... extra configuration
    config.middleware.insert_before ActionDispatch::RemoteIp, FourOFour, 'DelegatedClass'
  end
end

In this case, the DelegatedClass can be any other ruby class that will take control of the 404 implementing your own logic. This still needs to be a Rack application compatible. But nothing complicated.

class DelegatedClass
  def call(env)
    [200, {'Content-Type' => 'text/html'}, self ]
  end

  def each(&block)
    block.call(random_msg)
  end

  def random_msg
    ["Yo!, this is sad. I didn't know you got this. Sorry ",
     "Dear Mr. or Ms. I'm really sorry about this 404",
     'Such is life'
    ].sample
  end
end

Options

Skip specific formats

By default, FourOFour will catch any request format. A parameter can be passed to the middleware initialization in order to skip specific formats. The middleware will then ignore these request types.

Example: throw normal 404 page for json and xml formats:

  config.middleware.insert_before ActionDispatch::RemoteIp, FourOFour, 'DelegatedClass',
                                  ['application/json', 'application/xml']

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/SparkHub/four_o_four. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

License

The gem is available as open source under the terms of the MIT License