gonzalo-bulnes/dredd-rack

require 'capybara'
require 'rainbow'
require 'rake'
require 'rake/tasklib'

# This class is heavily inspired in the RSpec::Core::RakeTask, which
# was published under the MIT license by:
#
# Copyright (C) 2009 Chad Humphries, David Chelimsky
# Copyright (C) 2006 David Chelimsky, The RSpec Development Team
# Copyright (C) 2005 Steven Baker
#
# See https://github.com/rspec/rspec-core/blob/v3.2.2/lib/rspec/core/rake_task.rb
#
# Modifications are part of Dredd::Rack, published under the GNU GPLv3 ot later by:
#
# Copyright (C) 2015 Gonzalo Bulnes Guilpain
#
# See https://github.com/gonzalo-bulnes/dredd-rack/blob/v0.3.0/lib/dredd/rack/rake_task.rb

module Dredd
  module Rack

    # A clonable Rake task powered by a Dredd::Rack::Runner
    #
    # Examples:
    #
    #    require 'dredd/rack'
    #    Dredd::Rack::RakeTask.new # run it with `rake dredd`
    #
    #    # Customize the name or description of the Rake task:
    #    namespace :blueprint do
    #      desc 'Verify an API complies with its blueprint'
    #      Dredd::Rack::RakeTask.new(:verify)
    #    end
    #    # run it with `rake blueprint:verify`
    #
    class RakeTask < ::Rake::TaskLib

      # Return the task's name
      attr_reader :name

      # Return the task's description
      attr_reader :description

      # Return the Dredd::Rack::Runner instance
      attr_reader :runner

      # Define a task with a custom name, arguments and description
      def initialize(*args, &task_block)
        @name = args.shift || :dredd
        @description = 'Run Dredd::Rack API blueprint verification'
        @runner = Dredd::Rack::Runner.new(ENV['API_HOST'])

        desc description unless ::Rake.application.last_description
        rake_task = task name, *args do |task_args|
          task_block.call(*[self, task_args].slice(0, task_block.arity)) if task_block
          run_task(runner)
        end

        integrate_with_rails!(rake_task)
      end

      private

        def dredd_available?
          system ['which', Dredd::Rack.dredd_command].join(' ')
        end

        def dredd_connection_error?(exit_status)
          exit_status == 8
        end

        def command_message(runner)
          <<-eos.gsub /^( |\t)+/, ""
            #{runner.command}

          eos
        end

        def connection_error_message(runner)
          <<-eos.gsub /^( |\t)+/, ""

            #{Rainbow("Something went wrong.").red}
            Maybe your API is not being served at #{runner.api_endpoint}?

            Note that specifying a different host is easy:
            #{Rainbow('`rake blueprint:verify API_HOST=http://localhost:4567`').yellow}

          eos
        end

        def dredd_not_available_message
          <<-eos.gsub /^( |\t)+/, ""

            The #{Rainbow('dredd').red} blueprint testing tool is not available.
            You may want to install it in order to validate the API blueprints.

            Try #{Rainbow('`npm install dredd --global`').yellow} (use `sudo` if necessary)
            or see https://github.com/apiaryio/dredd for instructions.

          eos
        end

        def run_task(runner)
          abort dredd_not_available_message unless dredd_available?

          puts starting_message

          puts command_message(runner)

          success = runner.run
          exit_status = $?.exitstatus

          puts connection_error_message(runner) unless success if dredd_connection_error?(exit_status)

          abort unless exit_status == 0
        end

        def starting_message
          <<-eos.gsub /^( |\t)+/, ""

            #{Rainbow('Verify the API conformance against its blueprint.').blue}
          eos
        end

        def integrate_with_rails!(rake_task)
          rake_task.enhance([:environment]) if Rake::Task.task_defined? :environment
        end
    end
  end
end