Merge pull request #341 from javan/respect-fragment-cache-keys

Fix fragment_cache_key cache invalidation

Author: David Heinemeier Hansson

lib/jbuilder/jbuilder_template.rb

@@ -32,7 +32,7 @@ def partial!(*args)
   #   end
   def cache!(key=nil, options={})
     if @context.controller.perform_caching
-      value = ::Rails.cache.fetch(_cache_key(key, options), options) do
+      value = _cache_fragment_for(key, options) do
         _scope { yield self }
       end
 
@@ -102,9 +102,34 @@ def _render_partial(options)
     @context.render options
   end
 
+  def _cache_fragment_for(key, options, &block)
+    key = _cache_key(key, options)
+    _read_fragment_cache(key, options) || _write_fragment_cache(key, options, &block)
+  end
+
+  def _read_fragment_cache(key, options = nil)
+    @context.controller.instrument_fragment_cache :read_fragment, key do
+      ::Rails.cache.read(key, options)
+    end
+  end
+
+  def _write_fragment_cache(key, options = nil)
+    @context.controller.instrument_fragment_cache :write_fragment, key do
+      yield.tap do |value|
+        ::Rails.cache.write(key, value, options)
+      end
+    end
+  end
+
   def _cache_key(key, options)
     key = _fragment_name_with_digest(key, options)
-    key = url_for(key).split('://', 2).last if ::Hash === key
+
+    if @context.respond_to?(:fragment_cache_key)
+      key = @context.fragment_cache_key(key)
+    else
+      key = url_for(key).split('://', 2).last if ::Hash === key
+    end
+
     ::ActiveSupport::Cache.expand_cache_key(key, :jbuilder)
   end
 

test/jbuilder_template_test.rb

@@ -332,6 +332,35 @@ def assert_collection_rendered(result, context = nil)
     JBUILDER
   end
 
+  test "fragment caching uses fragment_cache_key" do
+    undef_context_methods :fragment_name_with_digest, :cache_fragment_name
+
+    @context.expects(:fragment_cache_key).with("cachekey")
+
+    jbuild <<-JBUILDER
+      json.cache! "cachekey" do
+        json.name "Cache"
+      end
+    JBUILDER
+  end
+
+  test "fragment caching instrumentation" do
+    undef_context_methods :fragment_name_with_digest, :cache_fragment_name
+
+    payloads = {}
+    ActiveSupport::Notifications.subscribe("read_fragment.action_controller") { |*args| payloads[:read_fragment] = args.last }
+    ActiveSupport::Notifications.subscribe("write_fragment.action_controller") { |*args| payloads[:write_fragment] = args.last }
+
+    jbuild <<-JBUILDER
+      json.cache! "cachekey" do
+        json.name "Cache"
+      end
+    JBUILDER
+
+    assert_equal "jbuilder/cachekey", payloads[:read_fragment][:key]
+    assert_equal "jbuilder/cachekey", payloads[:write_fragment][:key]
+  end
+
   test "current cache digest option accepts options" do
     undef_context_methods :fragment_name_with_digest