Add an option to always print enums as ints in Json API

https://github.com/google/protobuf/issues/2735

src/google/protobuf/util/internal/protostream_objectsource.cc

@@ -120,6 +120,7 @@ ProtoStreamObjectSource::ProtoStreamObjectSource(
       own_typeinfo_(true),
       type_(type),
       use_lower_camel_for_enums_(false),
+      use_ints_for_enums_(false),
       recursion_depth_(0),
       max_recursion_depth_(kDefaultMaxRecursionDepth),
       render_unknown_fields_(false),
@@ -135,6 +136,7 @@ ProtoStreamObjectSource::ProtoStreamObjectSource(
       own_typeinfo_(false),
       type_(type),
       use_lower_camel_for_enums_(false),
+      use_ints_for_enums_(false),
       recursion_depth_(0),
       max_recursion_depth_(kDefaultMaxRecursionDepth),
       render_unknown_fields_(false),
@@ -858,6 +860,12 @@ Status ProtoStreamObjectSource::RenderNonMessageField(
         break;
       }
 
+      // No need to lookup enum type if we need to render int.
+      if (use_ints_for_enums_) {
+        ow->RenderInt32(field_name, buffer32);
+        break;
+      }
+
       // Get the nested enum type for this field.
       // TODO(skarvaje): Avoid string manipulation. Find ways to speed this
       // up.

src/google/protobuf/util/internal/protostream_objectsource.h

@@ -110,6 +110,12 @@ class LIBPROTOBUF_EXPORT ProtoStreamObjectSource : public ObjectSource {
     use_lower_camel_for_enums_ = value;
   }
 
+  // Sets whether to always output enums as ints, by default this is off, and
+  // enums are rendered as strings.
+  void set_use_ints_for_enums(bool value) {
+    use_ints_for_enums_ = value;
+  }
+
   // Sets the max recursion depth of proto message to be deserialized. Proto
   // messages over this depth will fail to be deserialized.
   // Default value is 64.
@@ -285,6 +291,9 @@ class LIBPROTOBUF_EXPORT ProtoStreamObjectSource : public ObjectSource {
   // Whether to render enums using lowerCamelCase. Defaults to false.
   bool use_lower_camel_for_enums_;
 
+  // Whether to render enums as ints always. Defaults to false.
+  bool use_ints_for_enums_;
+
   // Tracks current recursion depth.
   mutable int recursion_depth_;
 

src/google/protobuf/util/internal/protostream_objectsource_test.cc

@@ -102,6 +102,7 @@ class ProtostreamObjectSourceTest
         mock_(),
         ow_(&mock_),
         use_lower_camel_for_enums_(false),
+        use_ints_for_enums_(false),
         add_trailing_zeros_(false) {
     helper_.ResetTypeInfo(Book::descriptor(), Proto3Message::descriptor());
   }
@@ -123,6 +124,7 @@ class ProtostreamObjectSourceTest
     google::protobuf::scoped_ptr<ProtoStreamObjectSource> os(
         helper_.NewProtoSource(&in_stream, GetTypeUrl(descriptor)));
     if (use_lower_camel_for_enums_) os->set_use_lower_camel_for_enums(true);
+    if (use_ints_for_enums_) os->set_use_ints_for_enums(true);
     os->set_max_recursion_depth(64);
     return os->WriteTo(&mock_);
   }
@@ -270,6 +272,8 @@ class ProtostreamObjectSourceTest
 
   void UseLowerCamelForEnums() { use_lower_camel_for_enums_ = true; }
 
+  void UseIntsForEnums() { use_ints_for_enums_ = true; }
+
   void AddTrailingZeros() { add_trailing_zeros_ = true; }
 
   testing::TypeInfoTestHelper helper_;
@@ -277,6 +281,7 @@ class ProtostreamObjectSourceTest
   ::testing::NiceMock<MockObjectWriter> mock_;
   ExpectingObjectWriter ow_;
   bool use_lower_camel_for_enums_;
+  bool use_ints_for_enums_;
   bool add_trailing_zeros_;
 };
 
@@ -498,6 +503,18 @@ TEST_P(ProtostreamObjectSourceTest, EnumCaseIsUnchangedByDefault) {
   DoTest(book, Book::descriptor());
 }
 
+TEST_P(ProtostreamObjectSourceTest, UseIntsForEnumsTest) {
+  Book book;
+  book.set_type(Book::ACTION_AND_ADVENTURE);
+
+  UseIntsForEnums();
+
+  ow_.StartObject("")
+      ->RenderInt32("type", 3)
+      ->EndObject();
+  DoTest(book, Book::descriptor());
+}
+
 TEST_P(ProtostreamObjectSourceTest, UnknownEnum) {
   Proto3Message message;
   message.set_enum_value(static_cast<Proto3Message::NestedEnum>(1234));

src/google/protobuf/util/json_util.cc

@@ -79,6 +79,7 @@ util::Status BinaryToJsonStream(TypeResolver* resolver,
   google::protobuf::Type type;
   RETURN_IF_ERROR(resolver->ResolveMessageType(type_url, &type));
   converter::ProtoStreamObjectSource proto_source(&in_stream, resolver, type);
+  proto_source.set_use_ints_for_enums(options.always_print_enums_as_ints);
   io::CodedOutputStream out_stream(json_output);
   converter::JsonObjectWriter json_writer(options.add_whitespace ? " " : "",
                                           &out_stream);

src/google/protobuf/util/json_util.h

@@ -61,9 +61,13 @@ struct JsonPrintOptions {
   // set to 0 will be omitted. Set this flag to true will override the default
   // behavior and print primitive fields regardless of their values.
   bool always_print_primitive_fields;
+  // Whether to always print enums as ints. By default they are rendered as
+  // strings.
+  bool always_print_enums_as_ints;
 
   JsonPrintOptions() : add_whitespace(false),
-                       always_print_primitive_fields(false) {
+                       always_print_primitive_fields(false),
+                       always_print_enums_as_ints(false) {
   }
 };
 

src/google/protobuf/util/json_util_test.cc

@@ -160,6 +160,29 @@ TEST_F(JsonUtilTest, TestDefaultValues) {
       ToJson(m, options));
 }
 
+TEST_F(JsonUtilTest, TestAlwaysPrintEnumsAsInts) {
+  TestMessage orig;
+  orig.set_enum_value(proto3::EnumType::BAR);
+  orig.add_repeated_enum_value(proto3::EnumType::FOO);
+  orig.add_repeated_enum_value(proto3::EnumType::BAR);
+
+  JsonPrintOptions print_options;
+  print_options.always_print_enums_as_ints = true;
+
+  string expected_json =
+    "{\"enumValue\":1,\"repeatedEnumValue\":[0,1]}";
+  EXPECT_EQ(expected_json, ToJson(orig, print_options));
+
+  TestMessage parsed;
+  JsonParseOptions parse_options;
+  ASSERT_TRUE(FromJson(expected_json, &parsed, parse_options));
+
+  EXPECT_EQ(proto3::EnumType::BAR, parsed.enum_value());
+  EXPECT_EQ(2, parsed.repeated_enum_value_size());
+  EXPECT_EQ(proto3::EnumType::FOO, parsed.repeated_enum_value(0));
+  EXPECT_EQ(proto3::EnumType::BAR, parsed.repeated_enum_value(1));
+}
+
 TEST_F(JsonUtilTest, ParseMessage) {
   // Some random message but good enough to verify that the parsing warpper
   // functions are working properly.