Lazy require memcache for session middleware

actionpack/lib/action_dispatch/middleware/session/mem_cache_store.rb

@@ -1,52 +1,47 @@
-require "active_support/core_ext/kernel/requires"
-begin
-  require_library_or_gem 'memcache'
+module ActionDispatch
+  module Session
+    class MemCacheStore < AbstractStore
+      def initialize(app, options = {})
+        require 'memcache'
 
-  module ActionDispatch
-    module Session
-      class MemCacheStore < AbstractStore
-        def initialize(app, options = {})
-          # Support old :expires option
-          options[:expire_after] ||= options[:expires]
+        # Support old :expires option
+        options[:expire_after] ||= options[:expires]
 
-          super
+        super
 
-          @default_options = {
-            :namespace => 'rack:session',
-            :memcache_server => 'localhost:11211'
-          }.merge(@default_options)
+        @default_options = {
+          :namespace => 'rack:session',
+          :memcache_server => 'localhost:11211'
+        }.merge(@default_options)
 
-          @pool = options[:cache] || MemCache.new(@default_options[:memcache_server], @default_options)
-          unless @pool.servers.any? { |s| s.alive? }
-            raise "#{self} unable to find server during initialization."
+        @pool = options[:cache] || MemCache.new(@default_options[:memcache_server], @default_options)
+        unless @pool.servers.any? { |s| s.alive? }
+          raise "#{self} unable to find server during initialization."
+        end
+        @mutex = Mutex.new
+
+        super
+      end
+
+      private
+        def get_session(env, sid)
+          sid ||= generate_sid
+          begin
+            session = @pool.get(sid) || {}
+          rescue MemCache::MemCacheError, Errno::ECONNREFUSED
+            session = {}
           end
-          @mutex = Mutex.new
-
-          super
+          [sid, session]
         end
 
-        private
-          def get_session(env, sid)
-            sid ||= generate_sid
-            begin
-              session = @pool.get(sid) || {}
-            rescue MemCache::MemCacheError, Errno::ECONNREFUSED
-              session = {}
-            end
-            [sid, session]
-          end
-
-          def set_session(env, sid, session_data)
-            options = env['rack.session.options']
-            expiry  = options[:expire_after] || 0
-            @pool.set(sid, session_data, expiry)
-            return true
-          rescue MemCache::MemCacheError, Errno::ECONNREFUSED
-            return false
-          end
-      end
+        def set_session(env, sid, session_data)
+          options = env['rack.session.options']
+          expiry  = options[:expire_after] || 0
+          @pool.set(sid, session_data, expiry)
+          return true
+        rescue MemCache::MemCacheError, Errno::ECONNREFUSED
+          return false
+        end
     end
   end
-rescue LoadError
-  # MemCache wasn't available so neither can the store be
 end