Better JSON casing support, renaming messages/fields

betterproto/tests/casing.json

@@ -0,0 +1,4 @@
+{
+  "camelCase": 1,
+  "snakeCase": "ONE"
+}

betterproto/tests/casing.proto

@@ -0,0 +1,12 @@
+syntax = "proto3";
+
+enum my_enum {
+  ZERO = 0;
+  ONE = 1;
+  TWO = 2;
+}
+
+message Test {
+  int32 camelCase = 1;
+  my_enum snake_case = 2;
+}

betterproto/tests/generate.py

@@ -72,7 +72,8 @@ if __name__ == "__main__":
         input_json = open(filename).read()
         parsed = Parse(input_json, imported.Test())
         serialized = parsed.SerializeToString()
-        serialized_json = MessageToJson(parsed, preserving_proto_field_name=True)
+        preserve = "casing" not in filename
+        serialized_json = MessageToJson(parsed, preserving_proto_field_name=preserve)
 
         s_loaded = json.loads(serialized_json)
         in_loaded = json.loads(input_json)

betterproto/tests/test_features.py

@@ -115,3 +115,34 @@ def test_oneof_support():
     assert betterproto.which_one_of(foo2, "group1")[0] == "bar"
     assert foo.bar == 0
     assert betterproto.which_one_of(foo2, "group2")[0] == ""
+
+
+def test_json_casing():
+    @dataclass
+    class CasingTest(betterproto.Message):
+        pascal_case: int = betterproto.int32_field(1)
+        camel_case: int = betterproto.int32_field(2)
+        snake_case: int = betterproto.int32_field(3)
+        kabob_case: int = betterproto.int32_field(4)
+
+    # Parsing should accept almost any input
+    test = CasingTest().from_dict(
+        {"PascalCase": 1, "camelCase": 2, "snake_case": 3, "kabob-case": 4}
+    )
+
+    assert test == CasingTest(1, 2, 3, 4)
+
+    # Serializing should be strict.
+    assert test.to_dict() == {
+        "pascalCase": 1,
+        "camelCase": 2,
+        "snakeCase": 3,
+        "kabobCase": 4,
+    }
+
+    assert test.to_dict(casing=betterproto.Casing.SNAKE) == {
+        "pascal_case": 1,
+        "camel_case": 2,
+        "snake_case": 3,
+        "kabob_case": 4,
+    }