From 1c028785ebeeb130e2d42a3ade5fc86bf9ab495d Mon Sep 17 00:00:00 2001
From: Alex Zherdev <alex_zherdev@acl.com>
Date: Wed, 16 Oct 2019 12:39:02 -0700
Subject: [PATCH] Introduce use_sha1_digests config option

---
 .../serializer/concerns/caching.rb            |  3 +-
 test/cache_test.rb                            | 33 +++++++++++++++++--
 2 files changed, 33 insertions(+), 3 deletions(-)

diff --git a/lib/active_model/serializer/concerns/caching.rb b/lib/active_model/serializer/concerns/caching.rb
index 7b3ff37e..cdcd5685 100644
--- a/lib/active_model/serializer/concerns/caching.rb
+++ b/lib/active_model/serializer/concerns/caching.rb
@@ -56,7 +56,8 @@ module ActiveModel
         def digest_caller_file(caller_line)
           serializer_file_path = caller_line[CALLER_FILE]
           serializer_file_contents = IO.read(serializer_file_path)
-          Digest::SHA1.hexdigest(serializer_file_contents)
+          algorithm = ActiveModelSerializers.config.use_sha1_digests ? Digest::SHA1 : Digest::MD5
+          algorithm.hexdigest(serializer_file_contents)
         rescue TypeError, Errno::ENOENT
           warn <<-EOF.strip_heredoc
             Cannot digest non-existent file: '#{caller_line}'.
diff --git a/test/cache_test.rb b/test/cache_test.rb
index f67f98a6..112e366c 100644
--- a/test/cache_test.rb
+++ b/test/cache_test.rb
@@ -446,15 +446,39 @@ module ActiveModelSerializers
     # rubocop:enable Metrics/AbcSize
 
     def test_uses_file_digest_in_cache_key
+      reset_cache_digest(@blog_serializer)
       render_object_with_cache(@blog)
-      file_digest = Digest::SHA1.hexdigest(File.open(__FILE__).read)
+      file_digest = Digest::MD5.hexdigest(File.open(__FILE__).read)
       key = "#{@blog.cache_key}/#{adapter.cache_key}/#{file_digest}"
       assert_equal(@blog_serializer.attributes, cache_store.fetch(key))
     end
 
+    def test_uses_sha1_digest_in_cache_key_when_configured
+      reset_cache_digest(@blog_serializer)
+      previous_use_sha1_digests = ActiveModelSerializers.config.use_sha1_digests
+      ActiveModelSerializers.config.use_sha1_digests = true
+      render_object_with_cache(@blog)
+      file_digest = Digest::SHA1.hexdigest(File.open(__FILE__).read)
+      key = "#{@blog.cache_key}/#{adapter.cache_key}/#{file_digest}"
+      assert_equal(@blog_serializer.attributes, cache_store.fetch(key))
+    ensure
+      ActiveModelSerializers.config.use_sha1_digests = previous_use_sha1_digests
+    end
+
     def test_cache_digest_definition
+      reset_cache_digest(@post_serializer)
+      file_digest = Digest::MD5.hexdigest(File.open(__FILE__).read)
+      assert_equal(file_digest, @post_serializer.class._cache_digest)
+    end
+
+    def test_cache_sha1_digest_definition
+      reset_cache_digest(@post_serializer)
+      previous_use_sha1_digests = ActiveModelSerializers.config.use_sha1_digests
+      ActiveModelSerializers.config.use_sha1_digests = true
       file_digest = Digest::SHA1.hexdigest(File.open(__FILE__).read)
       assert_equal(file_digest, @post_serializer.class._cache_digest)
+    ensure
+      ActiveModelSerializers.config.use_sha1_digests = previous_use_sha1_digests
     end
 
     def test_object_cache_keys
@@ -560,7 +584,7 @@ module ActiveModelSerializers
       path = file.path
       caller_line = "#{path}:1:in `<top (required)>'"
       file.close
-      assert_equal ActiveModel::Serializer.digest_caller_file(caller_line), Digest::SHA1.hexdigest(contents)
+      assert_equal ActiveModel::Serializer.digest_caller_file(caller_line), Digest::MD5.hexdigest(contents)
     ensure
       file.unlink
       FileUtils.remove_entry dir
@@ -715,5 +739,10 @@ module ActiveModelSerializers
     def adapter
       @serializable_resource.adapter
     end
+
+    def reset_cache_digest(serializer)
+      return unless serializer.class.instance_variable_defined?(:@_cache_digest)
+      serializer.class.remove_instance_variable(:@_cache_digest)
+    end
   end
 end