ensure_param_exists

Provide an easy way to verify you're receiving the correct parameters in an API request in Rails.

At PetroFeed we found that we were repeatedly writing the following code in our controllers:

class ArticleController
  before_filter :ensure_title_exists

  private

    def ensure_title_exists
      return unless params[:title].blank?
      render json: { success: false, message: "missing title parameter" }, status: 422
    end
end

To keep our controllers DRY we created the ensure_param gem which allows us to do the following:

class ArticleController
  ensure_param :title
end

Classy! Cut that duplicate code and keep your controllers DRY! 🔪

Installation

gem install ensure_param_exists

Usage

Add ensure_param_exists to your gemfile:

gem 'ensure_param_exists'

Mixin the functionality into a controller (or base controller):

class ArticleController
  include EnsureParamExists

  # ...
end

Define any parameters that you'd like check to make sure they exist with ensure_param, ensure_any_params, or ensure_all_params. The singular method takes a symbol, plurals take a symbol array, and any options at the end are passed to before_filter:

class ArticleController
  include EnsureParamExists

  # Make sure title exists
  ensure_param :title, only: [:show]

  # Make sure title or author exists
  ensure_any_params :title, :author, only: [:show]
  
  # Make sure title and author exists
  ensure_all_params :title, :author, except: [:index]
end

Copyright

Copyright (c) 2013 PetroFeed. See LICENSE for further details.

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