format_restricter_rails

This gem provides a simple way to block your Rails controller actions from processing unsupported formats. Without this, you'll eventually start seeing the following errors on your production site:

ActionView::MissingTemplate (Missing template tasks/index, application/index with {:locale=>[:en], :formats=>[:json], :variants=>[], :handlers=>[:erb, :builder, :raw, :ruby, :coffee, :jbuilder]}

Why are you getting these errors? Because you designed your snazzy controller action to only process html requests and someone decided to send it a .json request. Rails happily obliged, processed the action and failed when it couldn't find a corresponding json template to render.

When this happens, you may start defining respond_to calls in your actions. Once you realize that's going to explode your code base, you'll probably try to call respond_to :html at the top of your controller class in hopes that it will help. Sadly, it won't; and that's where this gem comes in. It provides a single controller class method called restrict_formats_to that does exactly what you want. When unallowed formats are requested, the controller will halt execution and return HTTP Error 406 Not acceptable.

Versioning Scheme

This gem uses semver.

Supported Rails Versions

Rails 4+.

Installation

Add this line to your Rails application's Gemfile:

gem 'format_restricter_rails'

And then execute:

$ bundle

Usage

Add restrict_formats_to to the top of a controller to restrict all actions in the controller to the specified format(s).

Example 1: Restrict all actions

class MySnazzyController < ApplicationController
  restrict_formats_to :html, :json

  def my_action_1
  end

  def my_action_2
  end
end

You can also use only: and except: options to target specific actions.

Example 2: Using the only: option

class MySnazzyController < ApplicationController
  restrict_formats_to :html, only: :my_action_1
  restrict_formats_to :json, only: [:my_action_2, :my_action_3]

  def my_action_1
  end

  def my_action_2
  end

  def my_action_3
  end
end

Example 2: Using the except: Option

class MySnazzyController < ApplicationController
  restrict_formats_to :html, except: :my_action_1

  def my_action_1
  end

  def my_action_2
  end
end

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/corlewsolutions/format_restricter_rails.

License

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