Merge aughr's entity store native ttl support

See rtomayko#33 for some caveats with this approach.

Conflicts:
	test/entitystore_test.rb

lib/rack/cache/entitystore.rb

@@ -58,7 +58,7 @@ def read(key)
       end
 
       # Write the Rack response body immediately and return the SHA1 key.
-      def write(body)
+      def write(body, ttl=nil)
         buf = []
         key, size = slurp(body) { |part| buf << part }
         @hash[key] = buf
@@ -119,7 +119,7 @@ def open(key)
         nil
       end
 
-      def write(body)
+      def write(body, ttl=nil)
         filename = ['buf', $$, Thread.current.object_id].join('-')
         temp_file = storage_path(filename)
         key, size =
@@ -227,10 +227,10 @@ def read(key)
         data
       end
 
-      def write(body)
+      def write(body, ttl=nil)
         buf = StringIO.new
         key, size = slurp(body){|part| buf.write(part) }
-        [key, size] if cache.set(key, buf.string)
+        [key, size] if cache.set(key, buf.string, ttl)
       end
 
       def purge(key)
@@ -267,10 +267,10 @@ def read(key)
         nil
       end
 
-      def write(body)
+      def write(body, ttl=0)
         buf = StringIO.new
         key, size = slurp(body){|part| buf.write(part) }
-        cache.set(key, buf.string, 0, false)
+        cache.set(key, buf.string, ttl, false)
         [key, size]
       end
 
@@ -315,10 +315,10 @@ def open(key)
         end
       end
 
-      def write(body)
+      def write(body, ttl=nil)
         buf = StringIO.new
         key, size = slurp(body){|part| buf.write(part) }
-        cache.put(key, buf.string)
+        cache.put(key, buf.string, ttl)
         [key, size]
       end
 

lib/rack/cache/metastore.rb

@@ -57,7 +57,11 @@ def store(request, response, entity_store)
       # write the response body to the entity store if this is the
       # original response.
       if response.headers['X-Content-Digest'].nil?
-        digest, size = entity_store.write(response.body)
+        if request.env['rack-cache.use_native_ttl'] && response.fresh?
+          digest, size = entity_store.write(response.body, response.ttl)
+        else
+          digest, size = entity_store.write(response.body)
+        end
         response.headers['X-Content-Digest'] = digest
         response.headers['Content-Length'] = size.to_s unless response.headers['Transfer-Encoding']
         response.body = entity_store.open(digest)

lib/rack/cache/options.rb

@@ -8,6 +8,8 @@ module Rack::Cache
   # below are stored in the Rack Environment as "rack-cache.<option>", where
   # <option> is the option name.
   module Options
+    extend self
+
     def self.option_accessor(key)
       name = option_name(key)
       define_method(key) { || options[name] }
@@ -95,6 +97,10 @@ def option_name(key)
     # default for compliance with RFC 2616.
     option_accessor :allow_revalidate
 
+    # Specifies whether the underlying entity store's native expiration should
+    # be used.
+    option_accessor :use_native_ttl
+
     # The underlying options Hash. During initialization (or outside of a
     # request), this is a default values Hash. During a request, this is the
     # Rack environment Hash. The default values Hash is merged in underneath
@@ -134,7 +140,8 @@ def initialize_options(options={})
         'rack-cache.default_ttl'      => 0,
         'rack-cache.private_headers'  => ['Authorization', 'Cookie'],
         'rack-cache.allow_reload'     => false,
-        'rack-cache.allow_revalidate' => false
+        'rack-cache.allow_revalidate' => false,
+        'rack-cache.use_native_ttl'   => false,
       }
       self.options = options
     end

test/entitystore_test.rb

@@ -24,6 +24,15 @@ def sha_like?
     data.should.equal 'My wild love went riding,'
   end
 
+  it 'takes a ttl parameter for #write' do
+    key, size = @store.write(['My wild love went riding,'], 0)
+    key.should.not.be.nil
+    key.should.be.sha_like
+
+    data = @store.read(key)
+    data.should.equal 'My wild love went riding,'
+  end
+
   it 'correctly determines whether cached body exists for key with #exist?' do
     key, size = @store.write(['She rode to the devil,'])
     @store.should.exist key