Intelligent OmniAuth strategy loader

lib/devise/omniauth/config.rb

@@ -2,25 +2,44 @@ module Devise
   module OmniAuth
     class Config
       attr_accessor :strategy
-      attr_reader :args
+      attr_reader :args, :options, :provider
 
       def initialize(provider, args)
         @provider = provider
         @args     = args
         @strategy = nil
+        @options = @args.last.is_a?(Hash) ? @args.last : {}
       end
 
       # open_id strategy can have configurable name
       def strategy_name
-        options = @args.last.is_a?(Hash) && @args.last
-        options && options[:name] ? options[:name] : @provider
+        options[:name] || @provider
       end
 
       def strategy_class
-        # NOTE: this could be bad if a third-party plugin does not define its strategy 
-        # under the OmniaAuth::Strategies namespace. May be better to search through 
-        # OmniAuth.strategies instead of autoloading.
-        ::OmniAuth::Strategies.const_get("#{::OmniAuth::Utils.camelize(@provider.to_s)}")
+        find_strategy || require_strategy
+      end
+
+      def find_strategy
+        ::OmniAuth.strategies.find do |strategy_class|
+          strategy_class.to_s =~ /#{::OmniAuth::Utils.camelize(strategy_name)}$/ ||
+            strategy_class.default_options[:name] == strategy_name
+        end
+      end
+
+      def require_strategy
+        if [:facebook, :github, :twitter].include?(provider.to_sym)
+          require "omniauth/strategies/#{provider}"
+        elsif options[:require]
+          require options[:require]
+        else
+          require "omniauth-#{provider}"
+        end
+        find_strategy || autoload_strategy
+      end
+
+      def autoload_strategy
+        ::OmniAuth::Strategies.const_get(::OmniAuth::Utils.camelize(provider.to_s))
       end
     end
   end

test/omniauth/config_test.rb

@@ -0,0 +1,58 @@
+require 'test_helper'
+
+class OmniAuthConfigTest < ActiveSupport::TestCase
+  def self.context(name, &block)
+    instance_eval(&block)
+  end
+
+  setup do
+    $: << File.dirname(__FILE__)
+  end
+
+  context 'Devise::OmniAuth::Config#strategy_name' do
+    test 'returns provider if no options given' do
+      config = Devise::OmniAuth::Config.new :facebook, [{}]
+      assert_equal :facebook, config.strategy_name
+    end
+    test 'returns provider if no name option given' do
+      config = Devise::OmniAuth::Config.new :facebook, [{ :other => :option }]
+      assert_equal :facebook, config.strategy_name
+    end
+    test 'returns name option' do
+      config = Devise::OmniAuth::Config.new :facebook, [{ :name => :github }]
+      assert_equal :github, config.strategy_name
+    end
+  end
+
+  context 'Devise::OmniAuth::Config#strategy_class' do
+    test "finds contrib strategies" do
+      config = Devise::OmniAuth::Config.new :facebook, [{}]
+      assert_equal OmniAuth::Strategies::Facebook, config.strategy_class
+    end
+    test "finds the strategy in OmniAuth's list by name" do
+      NamedTestStrategy = Class.new
+      NamedTestStrategy.send :include, OmniAuth::Strategy
+      NamedTestStrategy.option :name, :the_one
+
+      config = Devise::OmniAuth::Config.new :the_one, [{}]
+      assert_equal NamedTestStrategy, config.strategy_class
+    end
+    test "finds the strategy in OmniAuth's list by class name" do
+      UnNamedTestStrategy = Class.new
+      UnNamedTestStrategy.send :include, OmniAuth::Strategy
+
+      config = Devise::OmniAuth::Config.new :un_named_test_strategy, [{}]
+      assert_equal UnNamedTestStrategy, config.strategy_class
+    end
+    test 'attempts to load an as-yet not loaded plugin' do
+      config = Devise::OmniAuth::Config.new :my_strategy, [{}]
+      config_class = config.strategy_class
+      assert_equal MyStrategy, config_class
+    end
+    test 'allows the user to define a custom require path' do
+      config = Devise::OmniAuth::Config.new :my_other_strategy, [{:require => 'my_other_strategy'}]
+      config_class = config.strategy_class
+      assert_equal MyOtherStrategy, config_class
+    end
+  end
+end

test/omniauth/my_other_strategy.rb

@@ -0,0 +1,5 @@
+require 'omniauth'
+
+class MyOtherStrategy
+  include OmniAuth::Strategy
+end

test/omniauth/omniauth-my_strategy.rb

@@ -0,0 +1,5 @@
+require 'omniauth'
+
+class MyStrategy
+  include OmniAuth::Strategy
+end