When caching, return the object's cache_key up front if it's defined.

This will prevent objects PORO objects that don't have updated_at defined, from throwing an error.

Not as big a deal now that PORO objects can inherit ActiveModelSerializers::Model, but still necessary if it's not inherited for whatever reason.

Add the Adapter type to the cache key.

This prevents incorrect results when the same object is serialized with different adapters.

BF:

Cherry-pick of
040a97b9e9
which was a squash of
f89ed71058

from pr 1346

test/cache_test.rb

@@ -4,6 +4,21 @@ require 'tempfile'
 
 module ActiveModelSerializers
   class CacheTest < ActiveSupport::TestCase
+    UncachedAuthor = Class.new(Author) do
+      # To confirm cache_key is set using updated_at and cache_key option passed to cache
+      undef_method :cache_key
+    end
+
+    Article = Class.new(::Model) do
+      # To confirm error is raised when cache_key is not set and cache_key option not passed to cache
+      undef_method :cache_key
+    end
+
+    ArticleSerializer = Class.new(ActiveModel::Serializer) do
+      cache only: [:place], skip_digest: true
+      attributes :title
+    end
+
     InheritedRoleSerializer = Class.new(RoleSerializer) do
       cache key: 'inherited_role', only: [:name, :special_attribute]
       attribute :special_attribute
@@ -81,15 +96,26 @@ module ActiveModelSerializers
       assert_equal(nil, @comment_serializer.class._cache_key)
     end
 
-    def test_cache_key_interpolation_with_updated_at
-      render_object_with_cache(@author)
-      assert_equal(nil, cache_store.fetch(@author.cache_key))
-      assert_equal(@author_serializer.attributes.to_json, cache_store.fetch("#{@author_serializer.class._cache_key}/#{@author_serializer.object.id}-#{@author_serializer.object.updated_at.strftime("%Y%m%d%H%M%S%9N")}").to_json)
+
+    def test_error_is_raised_if_cache_key_is_not_defined_on_object_or_passed_as_cache_option
+      article = Article.new(title: 'Must Read')
+      assert_raises ActiveModel::Serializer::Adapter::CachedSerializer::UndefinedCacheKey do
+        render_object_with_cache(article)
+      end
+    end
+
+    def test_cache_key_interpolation_with_updated_at_when_cache_key_is_not_defined_on_object
+      uncached_author            = UncachedAuthor.new(name: 'Joao M. D. Moura')
+      uncached_author_serializer = AuthorSerializer.new(uncached_author)
+
+      render_object_with_cache(uncached_author)
+      key = cache_key_with_adapter("#{uncached_author_serializer.class._cache_key}/#{uncached_author_serializer.object.id}-#{uncached_author_serializer.object.updated_at.strftime("%Y%m%d%H%M%S%9N")}")
+      assert_equal(uncached_author_serializer.attributes.to_json, ActionController::Base.cache_store.fetch(key).to_json)
     end
 
     def test_default_cache_key_fallback
       render_object_with_cache(@comment)
-      assert_equal(@comment_serializer.attributes.to_json, cache_store.fetch(@comment.cache_key).to_json)
+      assert_equal(@comment_serializer.attributes.to_json, ActionController::Base.cache_store.fetch(cache_key_with_adapter(@comment.cache_key)).to_json)
     end
 
     def test_cache_options_definition
@@ -111,8 +137,8 @@ module ActiveModelSerializers
       Timecop.freeze(Time.current) do
         render_object_with_cache(@post)
 
-        assert_equal(@post_serializer.attributes, cache_store.fetch(@post.cache_key))
-        assert_equal(@comment_serializer.attributes, cache_store.fetch(@comment.cache_key))
+        assert_equal(@post_serializer.attributes, ActionController::Base.cache_store.fetch(cache_key_with_adapter(@post.cache_key)))
+        assert_equal(@comment_serializer.attributes, ActionController::Base.cache_store.fetch(cache_key_with_adapter(@comment.cache_key)))
       end
     end
 
@@ -122,8 +148,9 @@ module ActiveModelSerializers
         render_object_with_cache(@post)
 
         # Check if it cached the objects separately
-        assert_equal(@post_serializer.attributes,    cached_serialization(@post_serializer))
-        assert_equal(@comment_serializer.attributes, cached_serialization(@comment_serializer))
+        assert_equal(@post_serializer.attributes, ActionController::Base.cache_store.fetch(cache_key_with_adapter(@post.cache_key)))
+        assert_equal(@comment_serializer.attributes, ActionController::Base.cache_store.fetch(cache_key_with_adapter(@comment.cache_key)))
+
 
         # Simulating update on comments relationship with Post
         new_comment            = Comment.new(id: 2567, body: 'ZOMG A NEW COMMENT')
@@ -134,8 +161,8 @@ module ActiveModelSerializers
         render_object_with_cache(@post)
 
         # Check if the the new comment was cached
-        assert_equal(new_comment_serializer.attributes, cached_serialization(new_comment_serializer))
-        assert_equal(@post_serializer.attributes, cached_serialization(@post_serializer))
+        assert_equal(new_comment_serializer.attributes, ActionController::Base.cache_store.fetch(cache_key_with_adapter(new_comment.cache_key)))
+        assert_equal(@post_serializer.attributes, ActionController::Base.cache_store.fetch(cache_key_with_adapter(@post.cache_key)))
       end
     end
 
@@ -150,7 +177,7 @@ module ActiveModelSerializers
       hash = render_object_with_cache(@location)
 
       assert_equal(hash, expected_result)
-      assert_equal({ place: 'Nowhere' }, cache_store.fetch(@location.cache_key))
+      assert_equal({ place: 'Nowhere' }, ActionController::Base.cache_store.fetch(cache_key_with_adapter(@location.cache_key)))
     end
 
     def test_fragment_cache_with_inheritance
@@ -161,9 +188,14 @@ module ActiveModelSerializers
       refute_includes(base.keys, :special_attribute)
     end
 
+    def test_uses_adapter_in_cache_key
+      render_object_with_cache(@post)
+      assert_equal(@post_serializer.attributes, ActionController::Base.cache_store.fetch("#{@post.cache_key}/#{adapter.class.to_s.demodulize.underscore}"))
+    end
+
     def test_uses_file_digest_in_cache_key
       render_object_with_cache(@blog)
-      assert_equal(@blog_serializer.attributes, cache_store.fetch(@blog.cache_key_with_digest))
+      assert_equal(@blog_serializer.attributes, ActionController::Base.cache_store.fetch("#{cache_key_with_adapter(@blog.cache_key)}/#{@blog.class::FILE_DIGEST}"))
     end
 
     def test_cache_digest_definition
@@ -254,7 +286,16 @@ module ActiveModelSerializers
     private
 
     def render_object_with_cache(obj, options = {})
-      serializable(obj, options).serializable_hash
+      @serializable_resource = serializable(obj, options).serializable_hash
+      @serializable_resource.serializable_hash
+    end
+
+    def adapter
+      @serializable_resource.adapter
+    end
+
+    def cache_key_with_adapter(key)
+      "#{key}/#{adapter.name.underscore}"
     end
 
     def cache_store

test/fixtures/poro.rb

@@ -55,8 +55,8 @@ Bio      = Class.new(Model)
 Blog     = Class.new(Model) do
   FILE_DIGEST = Digest::MD5.hexdigest(File.open(__FILE__).read)
 
-  def cache_key_with_digest
-    "#{cache_key}/#{FILE_DIGEST}"
+  def digest
+    FILE_DIGEST
   end
 end
 Role     = Class.new(Model)