fix: Add no-pretty print option (#336)

proto/message.py

@@ -376,6 +376,7 @@ def to_json(
         use_integers_for_enums=True,
         including_default_value_fields=True,
         preserving_proto_field_name=False,
+        indent=2,
     ) -> str:
         """Given a message instance, serialize it to json
 
@@ -388,6 +389,9 @@ def to_json(
             preserving_proto_field_name (Optional(bool)): An option that
                 determines whether field name representations preserve
                 proto case (snake_case) or use lowerCamelCase. Default is False.
+            indent: The JSON object will be pretty-printed with this indent level.
+                An indent level of 0 or negative will only insert newlines.
+                Pass None for the most compact representation without newlines.
 
         Returns:
             str: The json string representation of the protocol buffer.
@@ -397,6 +401,7 @@ def to_json(
             use_integers_for_enums=use_integers_for_enums,
             including_default_value_fields=including_default_value_fields,
             preserving_proto_field_name=preserving_proto_field_name,
+            indent=indent,
         )
 
     def from_json(cls, payload, *, ignore_unknown_fields=False) -> "Message":

tests/test_json.py

@@ -28,6 +28,16 @@ class Squid(proto.Message):
     assert json == '{"massKg":100}'
 
 
+def test_message_to_json_no_indent():
+    class Squid(proto.Message):
+        mass_kg = proto.Field(proto.INT32, number=1)
+        name = proto.Field(proto.STRING, number=2)
+
+    s = Squid(mass_kg=100, name="no_new_lines_squid")
+    json = Squid.to_json(s, indent=None)
+    assert json == '{"massKg": 100, "name": "no_new_lines_squid"}'
+
+
 def test_message_from_json():
     class Squid(proto.Message):
         mass_kg = proto.Field(proto.INT32, number=1)