Simple YAML -> CouchDB fixture loader for Rails

couch_fixture.rb

# YAML -> CouchDB fixture loader for Rails
# ========================================
# by Jiri Stransky (http://twitter.com/jistr)
# for use with testing database instances only ;)
#
# What it does:
# * Loads fixtures from "test/fixtures" directory.
# * Permits use of ERB in the fixtures.
# * Uses CouchRest.
#
# Usage:
# 1) Put this file into "test" subdirectory of your Rails app (where test_helper.rb usually is).
# 2) Wherever you want to load fixtures into your CouchDB:
#   2a) Require this file.
#   2b) fixture_loader = CouchFixture::Loader.new("my database url")
#       fixture_loader.load_all


require 'yaml'
require 'erb'
require 'couchrest'

module CouchFixture
  class Loader
    RELATIVE_FIXTURES_PATH = '../fixtures'

    def initialize(db)
      case db
      when CouchRest::Database
        @db = db
      when String
        @db = CouchRest.database! db
      else
        raise 'CouchFixture::Loader can be initialized only with a database URL string or CouchRest::Database object'
      end
    end

    def load_all
      get_all_fixture_filenames.each do |filename|
        load_file filename
      end
    end

    def load(fixture)
      load_file(File.expand_path(RELATIVE_FIXTURES_PATH, __FILE__) + '/' + fixture + '.yml')
    end

    private

      def get_all_fixture_filenames
        fixture_dir = File.expand_path(RELATIVE_FIXTURES_PATH, __FILE__)
        Dir.glob("#{fixture_dir}/*.yml")
      end

      def load_file(filename)
        # the first level keys aren't important, we are only interested in values
        contents = YAML::load(erb_process_file(filename)).values

        contents.each do |document|
          last = document == contents.last

          # bulk save if not last, batch save always
          @db.save_doc(document, !last, true)
        end
      end

      def erb_process_file(filename)
        erb = ERB.new IO.read(filename)

        # make empty object for ERB binding
        bindable = Object.new
        class << bindable
          def get_binding
            binding
          end
        end

        erb.result(bindable.get_binding)
      end
  end
end