Doc updates, version bump for release

.github/workflows/ci.yml

@@ -14,10 +14,12 @@ jobs:
       - uses: dschep/install-pipenv-action@v1
       - name: Install dependencies
         run: |
-          sudo apt install protobuf-compiler
+          sudo apt install protobuf-compiler libprotobuf-dev
           pipenv install --dev
       - name: Run tests
         run: |
+          cp .env.default .env
+          pipenv run pip install -e .
           pipenv run generate
           pipenv run test
       - name: Build package
@@ -25,7 +27,7 @@ jobs:
         run: pipenv run python setup.py sdist
       - name: Publish package
         if: github.event_name == 'push' && startsWith(github.event.ref, 'refs/tags')
-        uses: pypa/gh-action-pypi-publish@master
+        uses: pypa/gh-action-pypi-publish@v1.0.0a0
         with:
           user: __token__
           password: ${{ secrets.pypi }}

Pipfile

@@ -14,6 +14,7 @@ rope = "*"
 protobuf = "*"
 jinja2 = "*"
 grpclib = "*"
+stringcase = "*"
 
 [requires]
 python_version = "3.7"

Pipfile.lock

@@ -1,7 +1,7 @@
 {
     "_meta": {
         "hash": {
-            "sha256": "f698150037f2a8ac554e4d37ecd4619ba35d1aa570f5b641d048ec9c6b23eb40"
+            "sha256": "28c38cd6c4eafb0b9ac9a64cf623145868fdee163111d3b941b34d23011db6ca"
         },
         "pipfile-spec": 6,
         "requires": {
@@ -147,6 +147,13 @@
                 "sha256:d16a0141ec1a18405cd4ce8b4613101da75da0e9a7aec5bdd4fa804d0e0eba73"
             ],
             "version": "==1.12.0"
+        },
+        "stringcase": {
+            "hashes": [
+                "sha256:48a06980661908efe8d9d34eab2b6c13aefa2163b3ced26972902e3bdfd87008"
+            ],
+            "index": "pypi",
+            "version": "==1.2.0"
         }
     },
     "develop": {
@@ -159,10 +166,10 @@
         },
         "attrs": {
             "hashes": [
-                "sha256:ec20e7a4825331c1b5ebf261d111e16fa9612c1f7a5e1f884f12bd53a664dfd2",
+                "sha256:08a96c641c3a74e44eb59afb61a24f2cb9f4d7188748e76ba4bb5edfa3cb7d1c",
-                "sha256:f913492e1663d3c36f502e5e9ba6cd13cf19d7fab50aa13239e420fef95e1396"
+                "sha256:f7b7ce16570fe9965acd6d30101a28f62fb4a7f9e926b3bbc9b61f8b04247e72"
             ],
-            "version": "==19.2.0"
+            "version": "==19.3.0"
         },
         "entrypoints": {
             "hashes": [
@@ -211,26 +218,30 @@
         },
         "mypy": {
             "hashes": [
-                "sha256:1d98fd818ad3128a5408148c9e4a5edce6ed6b58cc314283e631dd5d9216527b",
+                "sha256:1521c186a3d200c399bd5573c828ea2db1362af7209b2adb1bb8532cea2fb36f",
-                "sha256:22ee018e8fc212fe601aba65d3699689dd29a26410ef0d2cc1943de7bec7e3ac",
+                "sha256:31a046ab040a84a0fc38bc93694876398e62bc9f35eca8ccbf6418b7297f4c00",
-                "sha256:3a24f80776edc706ec8d05329e854d5b9e464cd332e25cde10c8da2da0a0db6c",
+                "sha256:3b1a411909c84b2ae9b8283b58b48541654b918e8513c20a400bb946aa9111ae",
-                "sha256:42a78944e80770f21609f504ca6c8173f7768043205b5ac51c9144e057dcf879",
+                "sha256:48c8bc99380575deb39f5d3400ebb6a8a1cb5cc669bbba4d3bb30f904e0a0e7d",
-                "sha256:4b2b20106973548975f0c0b1112eceb4d77ed0cafe0a231a1318f3b3a22fc795",
+                "sha256:540c9caa57a22d0d5d3c69047cc9dd0094d49782603eb03069821b41f9e970e9",
-                "sha256:591a9625b4d285f3ba69f541c84c0ad9e7bffa7794da3fa0585ef13cf95cb021",
+                "sha256:672e418425d957e276c291930a3921b4a6413204f53fe7c37cad7bc57b9a3391",
-                "sha256:5b4b70da3d8bae73b908a90bb2c387b977e59d484d22c604a2131f6f4397c1a3",
+                "sha256:6ed3b9b3fdc7193ea7aca6f3c20549b377a56f28769783a8f27191903a54170f",
-                "sha256:84edda1ffeda0941b2ab38ecf49302326df79947fa33d98cdcfbf8ca9cf0bb23",
+                "sha256:9371290aa2cad5ad133e4cdc43892778efd13293406f7340b9ffe99d5ec7c1d9",
-                "sha256:b2b83d29babd61b876ae375786960a5374bba0e4aba3c293328ca6ca5dc448dd",
+                "sha256:ace6ac1d0f87d4072f05b5468a084a45b4eda970e4d26704f201e06d47ab2990",
-                "sha256:cc4502f84c37223a1a5ab700649b5ab1b5e4d2bf2d426907161f20672a21930b",
+                "sha256:b428f883d2b3fe1d052c630642cc6afddd07d5cd7873da948644508be3b9d4a7",
-                "sha256:e29e24dd6e7f39f200a5bb55dcaa645d38a397dd5a6674f6042ef02df5795046"
+                "sha256:d5bf0e6ec8ba346a2cf35cb55bf4adfddbc6b6576fcc9e10863daa523e418dbb",
+                "sha256:d7574e283f83c08501607586b3167728c58e8442947e027d2d4c7dcd6d82f453",
+                "sha256:dc889c84241a857c263a2b1cd1121507db7d5b5f5e87e77147097230f374d10b",
+                "sha256:f4748697b349f373002656bf32fede706a0e713d67bfdcf04edf39b1f61d46eb"
             ],
             "index": "pypi",
-            "version": "==0.730"
+            "version": "==0.740"
         },
         "mypy-extensions": {
             "hashes": [
-                "sha256:a161e3b917053de87dbe469987e173e49fb454eca10ef28b48b384538cc11458"
+                "sha256:090fedd75945a69ae91ce1303b5824f428daf5a028d2f6ab8a299250a846f15d",
+                "sha256:2d82818f5bb3e369420cb3c4060a7970edba416647068eb4c5343488a6c604a8"
             ],
-            "version": "==0.4.2"
+            "version": "==0.4.3"
         },
         "packaging": {
             "hashes": [
@@ -300,20 +311,25 @@
         },
         "typed-ast": {
             "hashes": [
+                "sha256:1170afa46a3799e18b4c977777ce137bb53c7485379d9706af8a59f2ea1aa161",
                 "sha256:18511a0b3e7922276346bcb47e2ef9f38fb90fd31cb9223eed42c85d1312344e",
                 "sha256:262c247a82d005e43b5b7f69aff746370538e176131c32dda9cb0f324d27141e",
                 "sha256:2b907eb046d049bcd9892e3076c7a6456c93a25bebfe554e931620c90e6a25b0",
                 "sha256:354c16e5babd09f5cb0ee000d54cfa38401d8b8891eefa878ac772f827181a3c",
+                "sha256:48e5b1e71f25cfdef98b013263a88d7145879fbb2d5185f2a0c79fa7ebbeae47",
                 "sha256:4e0b70c6fc4d010f8107726af5fd37921b666f5b31d9331f0bd24ad9a088e631",
                 "sha256:630968c5cdee51a11c05a30453f8cd65e0cc1d2ad0d9192819df9978984529f4",
                 "sha256:66480f95b8167c9c5c5c87f32cf437d585937970f3fc24386f313a4c97b44e34",
                 "sha256:71211d26ffd12d63a83e079ff258ac9d56a1376a25bc80b1cdcdf601b855b90b",
+                "sha256:7954560051331d003b4e2b3eb822d9dd2e376fa4f6d98fee32f452f52dd6ebb2",
+                "sha256:838997f4310012cf2e1ad3803bce2f3402e9ffb71ded61b5ee22617b3a7f6b6e",
                 "sha256:95bd11af7eafc16e829af2d3df510cecfd4387f6453355188342c3e79a2ec87a",
                 "sha256:bc6c7d3fa1325a0c6613512a093bc2a2a15aeec350451cbdf9e1d4bffe3e3233",
                 "sha256:cc34a6f5b426748a507dd5d1de4c1978f2eb5626d51326e43280941206c209e1",
                 "sha256:d755f03c1e4a51e9b24d899561fec4ccaf51f210d52abdf8c07ee2849b212a36",
                 "sha256:d7c45933b1bdfaf9f36c579671fec15d25b06c8398f113dab64c18ed1adda01d",
                 "sha256:d896919306dd0aa22d0132f62a1b78d11aaf4c9fc5b3410d3c666b818191630a",
+                "sha256:fdc1c9bbf79510b76408840e009ed65958feba92a88833cdceecff93ae8fff66",
                 "sha256:ffde2fbfad571af120fcbfbbc61c72469e72f550d676c3342492a9dfdefb8f12"
             ],
             "version": "==1.4.0"

README.md

@@ -10,6 +10,7 @@ This project aims to provide an improved experience when using Protobuf / gRPC i
   - Enums
   - Dataclasses
   - `async`/`await`
+  - Timezone-aware `datetime` and `timedelta` objects
   - Relative imports
   - Mypy type checking
 
@@ -34,6 +35,8 @@ This project exists because I am unhappy with the state of the official Google p
   - Much code looks like C++ or Java ported 1:1 to Python
   - Capitalized function names like `HasField()` and `SerializeToString()`
   - Uses `SerializeToString()` rather than the built-in `__bytes__()`
+  - Special wrapped types don't use Python's `None`
+  - Timestamp/duration types don't use Python's built-in `datetime` module
 
 This project is a reimplementation from the ground up focused on idiomatic modern Python to help fix some of the above. While it may not be a 1:1 drop-in replacement due to changed method names and call patterns, the wire format is identical.
 
@@ -155,7 +158,7 @@ You can use it like so (enable async in the interactive shell first):
 EchoResponse(values=["hello", "hello"])
 
 >>> async for response in service.echo_stream(value="hello", extra_times=1)
-    print(response)
+        print(response)
 
 EchoStreamResponse(value="hello")
 EchoStreamResponse(value="hello")
@@ -168,6 +171,12 @@ Both serializing and parsing are supported to/from JSON and Python dictionaries
 - Dicts: `Message().to_dict()`, `Message().from_dict(...)`
 - JSON: `Message().to_json()`, `Message().from_json(...)`
 
+For compatibility the default is to convert field names to `camelCase`. You can control this behavior by passing a casing value, e.g:
+
+```py
+>>> MyMessage().to_dict(casing=betterproto.Casing.SNAKE)
+```
+
 ### Determining if a message was sent
 
 Sometimes it is useful to be able to determine whether a message has been sent on the wire. This is how the Google wrapper types work to let you know whether a value is unset, set as the default (zero value), or set as something else, for example.
@@ -238,6 +247,53 @@ Again this is a little different than the official Google code generator:
 ["foo", "foo's value"]
 ```
 
+### Well-Known Google Types
+
+Google provides several well-known message types like a timestamp, duration, and several wrappers used to provide optional zero value support. Each of these has a special JSON representation and is handled a little differently from normal messages. The Python mapping for these is as follows:
+
+| Google Message              | Python Type                              | Default                |
+| --------------------------- | ---------------------------------------- | ---------------------- |
+| `google.protobuf.duration`  | [`datetime.timedelta`][td]               | `0`                    |
+| `google.protobuf.timestamp` | Timezone-aware [`datetime.datetime`][dt] | `1970-01-01T00:00:00Z` |
+| `google.protobuf.*Value`    | `Optional[...]`                          | `None`                 |
+
+[td]: https://docs.python.org/3/library/datetime.html#timedelta-objects
+[dt]: https://docs.python.org/3/library/datetime.html#datetime.datetime
+
+For the wrapper types, the Python type corresponds to the wrapped type, e.g. `google.protobuf.BoolValue` becomes `Optional[bool]` while `google.protobuf.Int32Value` becomes `Optional[int]`. All of the optional values default to `None`, so don't forget to check for that possible state. Given:
+
+```protobuf
+syntax = "proto3";
+
+import "google/protobuf/duration.proto";
+import "google/protobuf/timestamp.proto";
+import "google/protobuf/wrappers.proto";
+
+message Test {
+  google.protobuf.BoolValue maybe = 1;
+  google.protobuf.Timestamp ts = 2;
+  google.protobuf.Duration duration = 3;
+}
+```
+
+You can do stuff like:
+
+```py
+>>> t = Test().from_dict({"maybe": True, "ts": "2019-01-01T12:00:00Z", "duration": "1.200s"})
+>>> t
+st(maybe=True, ts=datetime.datetime(2019, 1, 1, 12, 0, tzinfo=datetime.timezone.utc), duration=datetime.timedelta(seconds=1, microseconds=200000))
+
+>>> t.ts - t.duration
+datetime.datetime(2019, 1, 1, 11, 59, 58, 800000, tzinfo=datetime.timezone.utc)
+
+>>> t.ts.isoformat()
+'2019-01-01T12:00:00+00:00'
+
+>>> t.maybe = None
+>>> t.to_dict()
+{'ts': '2019-01-01T12:00:00Z', 'duration': '1.200s'}
+```
+
 ## Development
 
 First, make sure you have Python 3.7+ and `pipenv` installed, along with the official [Protobuf Compiler](https://github.com/protocolbuffers/protobuf/releases) for your platform. Then:
@@ -295,14 +351,14 @@ $ pipenv run tests
   - [x] Bytes as base64
   - [ ] Any support
   - [x] Enum strings
-  - [ ] Well known types support (timestamp, duration, wrappers)
+  - [x] Well known types support (timestamp, duration, wrappers)
-  - [ ] Support different casing (orig vs. camel vs. others?)
+  - [x] Support different casing (orig vs. camel vs. others?)
 - [ ] Async service stubs
   - [x] Unary-unary
   - [x] Server streaming response
   - [ ] Client streaming request
-- [ ] Renaming messages and fields to conform to Python name standards
+- [x] Renaming messages and fields to conform to Python name standards
-- [ ] Renaming clashes with language keywords and standard library top-level packages
+- [x] Renaming clashes with language keywords
 - [x] Python package
 - [x] Automate running tests
 - [ ] Cleanup!

betterproto/__init__.py

@@ -5,6 +5,7 @@ import json
 import struct
 from abc import ABC
 from base64 import b64encode, b64decode
+from datetime import datetime, timedelta, timezone
 from typing import (
     Any,
     AsyncGenerator,
@@ -24,6 +25,9 @@ from typing import (
 
 import grpclib.client
 import grpclib.const
+import stringcase
+
+from .casing import safe_snake_case
 
 # Proto 3 data types
 TYPE_ENUM = "enum"
@@ -101,6 +105,17 @@ WIRE_FIXED_64_TYPES = [TYPE_DOUBLE, TYPE_FIXED64, TYPE_SFIXED64]
 WIRE_LEN_DELIM_TYPES = [TYPE_STRING, TYPE_BYTES, TYPE_MESSAGE, TYPE_MAP]
 
 
+# Protobuf datetimes start at the Unix Epoch in 1970 in UTC.
+DATETIME_ZERO = datetime(1970, 1, 1, tzinfo=timezone.utc)
+
+
+class Casing(enum.Enum):
+    """Casing constants for serialization."""
+
+    CAMEL = stringcase.camelcase
+    SNAKE = stringcase.snakecase
+
+
 class _PLACEHOLDER:
     pass
 
@@ -108,18 +123,6 @@ class _PLACEHOLDER:
 PLACEHOLDER: Any = _PLACEHOLDER()
 
 
-def get_default(proto_type: str) -> Any:
-    """Get the default (zero value) for a given type."""
-    return {
-        TYPE_BOOL: False,
-        TYPE_FLOAT: 0.0,
-        TYPE_DOUBLE: 0.0,
-        TYPE_STRING: "",
-        TYPE_BYTES: b"",
-        TYPE_MAP: {},
-    }.get(proto_type, 0)
-
-
 @dataclasses.dataclass(frozen=True)
 class FieldMetadata:
     """Stores internal metadata used for parsing & serialization."""
@@ -129,9 +132,11 @@ class FieldMetadata:
     # Protobuf type name
     proto_type: str
     # Map information if the proto_type is a map
-    map_types: Optional[Tuple[str, str]]
+    map_types: Optional[Tuple[str, str]] = None
     # Groups several "one-of" fields together
-    group: Optional[str]
+    group: Optional[str] = None
+    # Describes the wrapped type (e.g. when using google.protobuf.BoolValue)
+    wraps: Optional[str] = None
 
     @staticmethod
     def get(field: dataclasses.Field) -> "FieldMetadata":
@@ -145,11 +150,14 @@ def dataclass_field(
     *,
     map_types: Optional[Tuple[str, str]] = None,
     group: Optional[str] = None,
+    wraps: Optional[str] = None,
 ) -> dataclasses.Field:
     """Creates a dataclass field with attached protobuf metadata."""
     return dataclasses.field(
         default=PLACEHOLDER,
-        metadata={"betterproto": FieldMetadata(number, proto_type, map_types, group)},
+        metadata={
+            "betterproto": FieldMetadata(number, proto_type, map_types, group, wraps)
+        },
     )
 
 
@@ -222,8 +230,10 @@ def bytes_field(number: int, group: Optional[str] = None) -> Any:
     return dataclass_field(number, TYPE_BYTES, group=group)
 
 
-def message_field(number: int, group: Optional[str] = None) -> Any:
+def message_field(
-    return dataclass_field(number, TYPE_MESSAGE, group=group)
+    number: int, group: Optional[str] = None, wraps: Optional[str] = None
+) -> Any:
+    return dataclass_field(number, TYPE_MESSAGE, group=group, wraps=wraps)
 
 
 def map_field(
@@ -274,7 +284,7 @@ def encode_varint(value: int) -> bytes:
     return bytes(b + [bits])
 
 
-def _preprocess_single(proto_type: str, value: Any) -> bytes:
+def _preprocess_single(proto_type: str, wraps: str, value: Any) -> bytes:
     """Adjusts values before serialization."""
     if proto_type in [
         TYPE_ENUM,
@@ -297,16 +307,37 @@ def _preprocess_single(proto_type: str, value: Any) -> bytes:
     elif proto_type == TYPE_STRING:
         return value.encode("utf-8")
     elif proto_type == TYPE_MESSAGE:
+        if isinstance(value, datetime):
+            # Convert the `datetime` to a timestamp message.
+            seconds = int(value.timestamp())
+            nanos = int(value.microsecond * 1e3)
+            value = _Timestamp(seconds=seconds, nanos=nanos)
+        elif isinstance(value, timedelta):
+            # Convert the `timedelta` to a duration message.
+            total_ms = value // timedelta(microseconds=1)
+            seconds = int(total_ms / 1e6)
+            nanos = int((total_ms % 1e6) * 1e3)
+            value = _Duration(seconds=seconds, nanos=nanos)
+        elif wraps:
+            if value is None:
+                return b""
+            value = _get_wrapper(wraps)(value=value)
+
         return bytes(value)
 
     return value
 
 
 def _serialize_single(
-    field_number: int, proto_type: str, value: Any, *, serialize_empty: bool = False
+    field_number: int,
+    proto_type: str,
+    value: Any,
+    *,
+    serialize_empty: bool = False,
+    wraps: str = "",
 ) -> bytes:
     """Serializes a single field and value."""
-    value = _preprocess_single(proto_type, value)
+    value = _preprocess_single(proto_type, wraps, value)
 
     output = b""
     if proto_type in WIRE_VARINT_TYPES:
@@ -319,7 +350,7 @@ def _serialize_single(
         key = encode_varint((field_number << 3) | 1)
         output += key + value
     elif proto_type in WIRE_LEN_DELIM_TYPES:
-        if len(value) or serialize_empty:
+        if len(value) or serialize_empty or wraps:
             key = encode_varint((field_number << 3) | 2)
             output += key + encode_varint(len(value)) + value
     else:
@@ -359,7 +390,6 @@ def parse_fields(value: bytes) -> Generator[ParsedField, None, None]:
     while i < len(value):
         start = i
         num_wire, i = decode_varint(value, i)
-        # print(num_wire, i)
         number = num_wire >> 3
         wire_type = num_wire & 0x7
 
@@ -375,8 +405,6 @@ def parse_fields(value: bytes) -> Generator[ParsedField, None, None]:
         elif wire_type == 5:
             decoded, i = value[i : i + 4], i + 4
 
-        # print(ParsedField(number=number, wire_type=wire_type, value=decoded))
-
         yield ParsedField(
             number=number, wire_type=wire_type, value=decoded, raw=value[start:i]
         )
@@ -392,15 +420,19 @@ class Message(ABC):
     register the message fields which get used by the serializers and parsers
     to go between Python, binary and JSON protobuf message representations.
     """
+    _serialized_on_wire: bool
+    _unknown_fields: bytes
+    _group_map: Dict[str, dict]
 
     def __post_init__(self) -> None:
         # Set a default value for each field in the class after `__init__` has
         # already been run.
-        group_map = {"fields": {}, "groups": {}}
+        group_map: Dict[str, dict] = {"fields": {}, "groups": {}}
         for field in dataclasses.fields(self):
             meta = FieldMetadata.get(field)
 
             if meta.group:
+                # This is part of a one-of group.
                 group_map["fields"][field.name] = meta.group
 
                 if meta.group not in group_map["groups"]:
@@ -450,6 +482,11 @@ class Message(ABC):
             meta = FieldMetadata.get(field)
             value = getattr(self, field.name)
 
+            if value is None:
+                # Optional items should be skipped. This is used for the Google
+                # wrapper types.
+                continue
+
             # Being selected in a a group means this field is the one that is
             # currently set in a `oneof` group, so it must be serialized even
             # if the value is the default zero value.
@@ -457,42 +494,48 @@ class Message(ABC):
             if meta.group and self._group_map["groups"][meta.group]["current"] == field:
                 selected_in_group = True
 
-            if isinstance(value, list):
+            serialize_empty = False
-                if not len(value) and not selected_in_group:
+            if isinstance(value, Message) and value._serialized_on_wire:
-                    # Empty values are not serialized
+                # Empty messages can still be sent on the wire if they were
-                    continue
+                # set (or received empty).
+                serialize_empty = True
 
+            if value == self._get_field_default(field, meta) and not (
+                selected_in_group or serialize_empty
+            ):
+                # Default (zero) values are not serialized. Two exceptions are
+                # if this is the selected oneof item or if we know we have to
+                # serialize an empty message (i.e. zero value was explicitly
+                # set by the user).
+                continue
+
+            if isinstance(value, list):
                 if meta.proto_type in PACKED_TYPES:
                     # Packed lists look like a length-delimited field. First,
                     # preprocess/encode each value into a buffer and then
                     # treat it like a field of raw bytes.
                     buf = b""
                     for item in value:
-                        buf += _preprocess_single(meta.proto_type, item)
+                        buf += _preprocess_single(meta.proto_type, "", item)
                     output += _serialize_single(meta.number, TYPE_BYTES, buf)
                 else:
                     for item in value:
-                        output += _serialize_single(meta.number, meta.proto_type, item)
+                        output += _serialize_single(
+                            meta.number, meta.proto_type, item, wraps=meta.wraps or ""
+                        )
             elif isinstance(value, dict):
-                if not len(value) and not selected_in_group:
-                    # Empty values are not serialized
-                    continue
-
                 for k, v in value.items():
                     assert meta.map_types
                     sk = _serialize_single(1, meta.map_types[0], k)
                     sv = _serialize_single(2, meta.map_types[1], v)
                     output += _serialize_single(meta.number, meta.proto_type, sk + sv)
             else:
-                if value == get_default(meta.proto_type) and not selected_in_group:
-                    # Default (zero) values are not serialized
-                    continue
-
-                serialize_empty = False
-                if isinstance(value, Message) and value._serialized_on_wire:
-                    serialize_empty = True
                 output += _serialize_single(
-                    meta.number, meta.proto_type, value, serialize_empty=serialize_empty
+                    meta.number,
+                    meta.proto_type,
+                    value,
+                    serialize_empty=serialize_empty,
+                    wraps=meta.wraps or "",
                 )
 
         return output + self._unknown_fields
@@ -500,30 +543,45 @@ class Message(ABC):
     # For compatibility with other libraries
     SerializeToString = __bytes__
 
-    def _cls_for(self, field: dataclasses.Field, index: int = 0) -> Type:
+    def _type_hint(self, field_name: str) -> Type:
-        """Get the message class for a field from the type hints."""
         module = inspect.getmodule(self.__class__)
         type_hints = get_type_hints(self.__class__, vars(module))
-        cls = type_hints[field.name]
+        return type_hints[field_name]
+
+    def _cls_for(self, field: dataclasses.Field, index: int = 0) -> Type:
+        """Get the message class for a field from the type hints."""
+        cls = self._type_hint(field.name)
         if hasattr(cls, "__args__") and index >= 0:
-            cls = type_hints[field.name].__args__[index]
+            cls = cls.__args__[index]
         return cls
 
     def _get_field_default(self, field: dataclasses.Field, meta: FieldMetadata) -> Any:
-        t = self._cls_for(field, index=-1)
+        t = self._type_hint(field.name)
 
         value: Any = 0
-        if meta.proto_type == TYPE_MAP:
+        if hasattr(t, "__origin__"):
-            # Maps cannot be repeated, so we check these first.
+            if t.__origin__ == dict:
-            value = {}
+                # This is some kind of map (dict in Python).
-        elif hasattr(t, "__args__") and len(t.__args__) == 1:
+                value = {}
-            # Anything else with type args is a list.
+            elif t.__origin__ == list:
-            value = []
+                # This is some kind of list (repeated) field.
-        elif meta.proto_type == TYPE_MESSAGE:
+                value = []
-            # Message means creating an instance of the right type.
+            elif t.__origin__ == Union and t.__args__[1] == type(None):
-            value = t()
+                # This is an optional (wrapped) field. For setting the default we
+                # really don't care what kind of field it is.
+                value = None
+            else:
+                value = t()
+        elif issubclass(t, Enum):
+            # Enums always default to zero.
+            value = 0
+        elif t == datetime:
+            # Offsets are relative to 1970-01-01T00:00:00Z
+            value = DATETIME_ZERO
         else:
-            value = get_default(meta.proto_type)
+            # This is either a primitive scalar or another message type. Calling
+            # it should result in its zero value.
+            value = t()
 
         return value
 
@@ -540,6 +598,9 @@ class Message(ABC):
             elif meta.proto_type in [TYPE_SINT32, TYPE_SINT64]:
                 # Undo zig-zag encoding
                 value = (value >> 1) ^ (-(value & 1))
+            elif meta.proto_type == TYPE_BOOL:
+                # Booleans use a varint encoding, so convert it to true/false.
+                value = value > 0
         elif wire_type in [WIRE_FIXED_32, WIRE_FIXED_64]:
             fmt = _pack_fmt(meta.proto_type)
             value = struct.unpack(fmt, value)[0]
@@ -548,8 +609,18 @@ class Message(ABC):
                 value = value.decode("utf-8")
             elif meta.proto_type == TYPE_MESSAGE:
                 cls = self._cls_for(field)
-                value = cls().parse(value)
+
-                value._serialized_on_wire = True
+                if cls == datetime:
+                    value = _Timestamp().parse(value).to_datetime()
+                elif cls == timedelta:
+                    value = _Duration().parse(value).to_timedelta()
+                elif meta.wraps:
+                    # This is a Google wrapper value message around a single
+                    # scalar type.
+                    value = _get_wrapper(meta.wraps)().parse(value).value
+                else:
+                    value = cls().parse(value)
+                    value._serialized_on_wire = True
             elif meta.proto_type == TYPE_MAP:
                 # TODO: This is slow, use a cache to make it faster since each
                 #       key/value pair will recreate the class.
@@ -624,48 +695,59 @@ class Message(ABC):
     def FromString(cls: Type[T], data: bytes) -> T:
         return cls().parse(data)
 
-    def to_dict(self) -> dict:
+    def to_dict(self, casing: Casing = Casing.CAMEL) -> dict:
         """
         Returns a dict representation of this message instance which can be
-        used to serialize to e.g. JSON.
+        used to serialize to e.g. JSON. Defaults to camel casing for
+        compatibility but can be set to other modes.
         """
         output: Dict[str, Any] = {}
         for field in dataclasses.fields(self):
             meta = FieldMetadata.get(field)
             v = getattr(self, field.name)
+            cased_name = casing(field.name).rstrip("_") # type: ignore
             if meta.proto_type == "message":
-                if isinstance(v, list):
+                if isinstance(v, datetime):
+                    if v != DATETIME_ZERO:
+                        output[cased_name] = _Timestamp.timestamp_to_json(v)
+                elif isinstance(v, timedelta):
+                    if v != timedelta(0):
+                        output[cased_name] = _Duration.delta_to_json(v)
+                elif meta.wraps:
+                    if v is not None:
+                        output[cased_name] = v
+                elif isinstance(v, list):
                     # Convert each item.
                     v = [i.to_dict() for i in v]
-                    output[field.name] = v
+                    output[cased_name] = v
                 elif v._serialized_on_wire:
-                    output[field.name] = v.to_dict()
+                    output[cased_name] = v.to_dict()
             elif meta.proto_type == "map":
                 for k in v:
                     if hasattr(v[k], "to_dict"):
                         v[k] = v[k].to_dict()
 
                 if v:
-                    output[field.name] = v
+                    output[cased_name] = v
-            elif v != get_default(meta.proto_type):
+            elif v != self._get_field_default(field, meta):
                 if meta.proto_type in INT_64_TYPES:
                     if isinstance(v, list):
-                        output[field.name] = [str(n) for n in v]
+                        output[cased_name] = [str(n) for n in v]
                     else:
-                        output[field.name] = str(v)
+                        output[cased_name] = str(v)
                 elif meta.proto_type == TYPE_BYTES:
                     if isinstance(v, list):
-                        output[field.name] = [b64encode(b).decode("utf8") for b in v]
+                        output[cased_name] = [b64encode(b).decode("utf8") for b in v]
                     else:
-                        output[field.name] = b64encode(v).decode("utf8")
+                        output[cased_name] = b64encode(v).decode("utf8")
                 elif meta.proto_type == TYPE_ENUM:
-                    enum_values = list(self._cls_for(field))
+                    enum_values = list(self._cls_for(field)) # type: ignore
                     if isinstance(v, list):
-                        output[field.name] = [enum_values[e].name for e in v]
+                        output[cased_name] = [enum_values[e].name for e in v]
                     else:
-                        output[field.name] = enum_values[v].name
+                        output[cased_name] = enum_values[v].name
                 else:
-                    output[field.name] = v
+                    output[cased_name] = v
         return output
 
     def from_dict(self: T, value: dict) -> T:
@@ -674,44 +756,58 @@ class Message(ABC):
         returns the instance itself and is therefore assignable and chainable.
         """
         self._serialized_on_wire = True
-        for field in dataclasses.fields(self):
+        fields_by_name = {f.name: f for f in dataclasses.fields(self)}
-            meta = FieldMetadata.get(field)
+        for key in value:
-            if field.name in value and value[field.name] is not None:
+            snake_cased = safe_snake_case(key)
-                if meta.proto_type == "message":
+            if snake_cased in fields_by_name:
-                    v = getattr(self, field.name)
+                field = fields_by_name[snake_cased]
-                    # print(v, value[field.name])
+                meta = FieldMetadata.get(field)
-                    if isinstance(v, list):
-                        cls = self._cls_for(field)
-                        for i in range(len(value[field.name])):
-                            v.append(cls().from_dict(value[field.name][i]))
-                    else:
-                        v.from_dict(value[field.name])
-                elif meta.map_types and meta.map_types[1] == TYPE_MESSAGE:
-                    v = getattr(self, field.name)
-                    cls = self._cls_for(field, index=1)
-                    for k in value[field.name]:
-                        v[k] = cls().from_dict(value[field.name][k])
-                else:
-                    v = value[field.name]
-                    if meta.proto_type in INT_64_TYPES:
-                        if isinstance(value[field.name], list):
-                            v = [int(n) for n in value[field.name]]
-                        else:
-                            v = int(value[field.name])
-                    elif meta.proto_type == TYPE_BYTES:
-                        if isinstance(value[field.name], list):
-                            v = [b64decode(n) for n in value[field.name]]
-                        else:
-                            v = b64decode(value[field.name])
-                    elif meta.proto_type == TYPE_ENUM:
-                        enum_cls = self._cls_for(field)
-                        if isinstance(v, list):
-                            v = [enum_cls.from_string(e) for e in v]
-                        elif isinstance(v, str):
-                            v = enum_cls.from_string(v)
 
-                    if v is not None:
+                if value[key] is not None:
-                        setattr(self, field.name, v)
+                    if meta.proto_type == "message":
+                        v = getattr(self, field.name)
+                        if isinstance(v, list):
+                            cls = self._cls_for(field)
+                            for i in range(len(value[key])):
+                                v.append(cls().from_dict(value[key][i]))
+                        elif isinstance(v, datetime):
+                            v = datetime.fromisoformat(
+                                value[key].replace("Z", "+00:00")
+                            )
+                            setattr(self, field.name, v)
+                        elif isinstance(v, timedelta):
+                            v = timedelta(seconds=float(value[key][:-1]))
+                            setattr(self, field.name, v)
+                        elif meta.wraps:
+                            setattr(self, field.name, value[key])
+                        else:
+                            v.from_dict(value[key])
+                    elif meta.map_types and meta.map_types[1] == TYPE_MESSAGE:
+                        v = getattr(self, field.name)
+                        cls = self._cls_for(field, index=1)
+                        for k in value[key]:
+                            v[k] = cls().from_dict(value[key][k])
+                    else:
+                        v = value[key]
+                        if meta.proto_type in INT_64_TYPES:
+                            if isinstance(value[key], list):
+                                v = [int(n) for n in value[key]]
+                            else:
+                                v = int(value[key])
+                        elif meta.proto_type == TYPE_BYTES:
+                            if isinstance(value[key], list):
+                                v = [b64decode(n) for n in value[key]]
+                            else:
+                                v = b64decode(value[key])
+                        elif meta.proto_type == TYPE_ENUM:
+                            enum_cls = self._cls_for(field)
+                            if isinstance(v, list):
+                                v = [enum_cls.from_string(e) for e in v]
+                            elif isinstance(v, str):
+                                v = enum_cls.from_string(v)
+
+                        if v is not None:
+                            setattr(self, field.name, v)
         return self
 
     def to_json(self, indent: Union[None, int, str] = None) -> str:
@@ -743,6 +839,140 @@ def which_one_of(message: Message, group_name: str) -> Tuple[str, Any]:
     return (field.name, getattr(message, field.name))
 
 
+@dataclasses.dataclass
+class _Duration(Message):
+    # Signed seconds of the span of time. Must be from -315,576,000,000 to
+    # +315,576,000,000 inclusive. Note: these bounds are computed from: 60
+    # sec/min * 60 min/hr * 24 hr/day * 365.25 days/year * 10000 years
+    seconds: int = int64_field(1)
+    # Signed fractions of a second at nanosecond resolution of the span of time.
+    # Durations less than one second are represented with a 0 `seconds` field and
+    # a positive or negative `nanos` field. For durations of one second or more,
+    # a non-zero value for the `nanos` field must be of the same sign as the
+    # `seconds` field. Must be from -999,999,999 to +999,999,999 inclusive.
+    nanos: int = int32_field(2)
+
+    def to_timedelta(self) -> timedelta:
+        return timedelta(seconds=self.seconds, microseconds=self.nanos / 1e3)
+
+    @staticmethod
+    def delta_to_json(delta: timedelta) -> str:
+        parts = str(delta.total_seconds()).split(".")
+        if len(parts) > 1:
+            while len(parts[1]) not in [3, 6, 9]:
+                parts[1] = parts[1] + "0"
+        return ".".join(parts) + "s"
+
+
+@dataclasses.dataclass
+class _Timestamp(Message):
+    # Represents seconds of UTC time since Unix epoch 1970-01-01T00:00:00Z. Must
+    # be from 0001-01-01T00:00:00Z to 9999-12-31T23:59:59Z inclusive.
+    seconds: int = int64_field(1)
+    # Non-negative fractions of a second at nanosecond resolution. Negative
+    # second values with fractions must still have non-negative nanos values that
+    # count forward in time. Must be from 0 to 999,999,999 inclusive.
+    nanos: int = int32_field(2)
+
+    def to_datetime(self) -> datetime:
+        ts = self.seconds + (self.nanos / 1e9)
+        return datetime.fromtimestamp(ts, tz=timezone.utc)
+
+    @staticmethod
+    def timestamp_to_json(dt: datetime) -> str:
+        nanos = dt.microsecond * 1e3
+        copy = dt.replace(microsecond=0, tzinfo=None)
+        result = copy.isoformat()
+        if (nanos % 1e9) == 0:
+            # If there are 0 fractional digits, the fractional
+            # point '.' should be omitted when serializing.
+            return result + "Z"
+        if (nanos % 1e6) == 0:
+            # Serialize 3 fractional digits.
+            return result + ".%03dZ" % (nanos / 1e6)
+        if (nanos % 1e3) == 0:
+            # Serialize 6 fractional digits.
+            return result + ".%06dZ" % (nanos / 1e3)
+        # Serialize 9 fractional digits.
+        return result + ".%09dZ" % nanos
+
+
+class _WrappedMessage(Message):
+    """
+    Google protobuf wrapper types base class. JSON representation is just the
+    value itself.
+    """
+    value: Any
+
+    def to_dict(self, casing: Casing = Casing.CAMEL) -> Any:
+        return self.value
+
+    def from_dict(self: T, value: Any) -> T:
+        if value is not None:
+            self.value = value
+        return self
+
+
+@dataclasses.dataclass
+class _BoolValue(_WrappedMessage):
+    value: bool = bool_field(1)
+
+
+@dataclasses.dataclass
+class _Int32Value(_WrappedMessage):
+    value: int = int32_field(1)
+
+
+@dataclasses.dataclass
+class _UInt32Value(_WrappedMessage):
+    value: int = uint32_field(1)
+
+
+@dataclasses.dataclass
+class _Int64Value(_WrappedMessage):
+    value: int = int64_field(1)
+
+
+@dataclasses.dataclass
+class _UInt64Value(_WrappedMessage):
+    value: int = uint64_field(1)
+
+
+@dataclasses.dataclass
+class _FloatValue(_WrappedMessage):
+    value: float = float_field(1)
+
+
+@dataclasses.dataclass
+class _DoubleValue(_WrappedMessage):
+    value: float = double_field(1)
+
+
+@dataclasses.dataclass
+class _StringValue(_WrappedMessage):
+    value: str = string_field(1)
+
+
+@dataclasses.dataclass
+class _BytesValue(_WrappedMessage):
+    value: bytes = bytes_field(1)
+
+
+def _get_wrapper(proto_type: str) -> Type:
+    """Get the wrapper message class for a wrapped type."""
+    return {
+        TYPE_BOOL: _BoolValue,
+        TYPE_INT32: _Int32Value,
+        TYPE_UINT32: _UInt32Value,
+        TYPE_INT64: _Int64Value,
+        TYPE_UINT64: _UInt64Value,
+        TYPE_FLOAT: _FloatValue,
+        TYPE_DOUBLE: _DoubleValue,
+        TYPE_STRING: _StringValue,
+        TYPE_BYTES: _BytesValue,
+    }[proto_type]
+
+
 class ServiceStub(ABC):
     """
     Base class for async gRPC service stubs.

betterproto/casing.py

@@ -0,0 +1,41 @@
+import stringcase
+
+
+def safe_snake_case(value: str) -> str:
+    """Snake case a value taking into account Python keywords."""
+    value = stringcase.snakecase(value)
+    if value in [
+        "and",
+        "as",
+        "assert",
+        "break",
+        "class",
+        "continue",
+        "def",
+        "del",
+        "elif",
+        "else",
+        "except",
+        "finally",
+        "for",
+        "from",
+        "global",
+        "if",
+        "import",
+        "in",
+        "is",
+        "lambda",
+        "nonlocal",
+        "not",
+        "or",
+        "pass",
+        "raise",
+        "return",
+        "try",
+        "while",
+        "with",
+        "yield",
+    ]:
+        # https://www.python.org/dev/peps/pep-0008/#descriptive-naming-styles
+        value += "_"
+    return value

betterproto/plugin.py

@@ -16,6 +16,8 @@ except ImportError:
     )
     raise SystemExit(1)
 
+import stringcase
+
 from google.protobuf.compiler import plugin_pb2 as plugin
 from google.protobuf.descriptor_pb2 import (
     DescriptorProto,
@@ -25,11 +27,20 @@ from google.protobuf.descriptor_pb2 import (
     ServiceDescriptorProto,
 )
 
+from betterproto.casing import safe_snake_case
 
-def snake_case(value: str) -> str:
+
-    return (
+WRAPPER_TYPES = {
-        re.sub(r"(?<=[a-z])[A-Z]|[A-Z](?=[^A-Z])", r"_\g<0>", value).lower().strip("_")
+    "google.protobuf.DoubleValue": "float",
-    )
+    "google.protobuf.FloatValue": "float",
+    "google.protobuf.Int64Value": "int",
+    "google.protobuf.UInt64Value": "int",
+    "google.protobuf.Int32Value": "int",
+    "google.protobuf.UInt32Value": "int",
+    "google.protobuf.BoolValue": "bool",
+    "google.protobuf.StringValue": "str",
+    "google.protobuf.BytesValue": "bytes",
+}
 
 
 def get_ref_type(package: str, imports: set, type_name: str) -> str:
@@ -37,15 +48,33 @@ def get_ref_type(package: str, imports: set, type_name: str) -> str:
     Return a Python type name for a proto type reference. Adds the import if
     necessary.
     """
+    # If the package name is a blank string, then this should still work
+    # because by convention packages are lowercase and message/enum types are
+    # pascal-cased. May require refactoring in the future.
     type_name = type_name.lstrip(".")
+
+    if type_name in WRAPPER_TYPES:
+        return f"Optional[{WRAPPER_TYPES[type_name]}]"
+
+    if type_name == "google.protobuf.Duration":
+        return "timedelta"
+
+    if type_name == "google.protobuf.Timestamp":
+        return "datetime"
+
     if type_name.startswith(package):
-        # This is the current package, which has nested types flattened.
+        parts = type_name.lstrip(package).lstrip(".").split(".")
-        type_name = f'"{type_name.lstrip(package).lstrip(".").replace(".", "")}"'
+        if len(parts) == 1 or (len(parts) > 1 and parts[0][0] == parts[0][0].upper()):
+            # This is the current package, which has nested types flattened.
+            # foo.bar_thing => FooBarThing
+            cased = [stringcase.pascalcase(part) for part in parts]
+            type_name = f'"{"".join(cased)}"'
 
     if "." in type_name:
         # This is imported from another package. No need
         # to use a forward ref and we need to add the import.
         parts = type_name.split(".")
+        parts[-1] = stringcase.pascalcase(parts[-1])
         imports.add(f"from .{'.'.join(parts[:-2])} import {parts[-2]}")
         type_name = f"{parts[-2]}.{parts[-1]}"
 
@@ -122,7 +151,7 @@ def get_comment(proto_file, path: List[int]) -> str:
 
             if path[-2] == 2 and path[-4] != 6:
                 # This is a field
-                return "    # " + "    # ".join(lines)
+                return "    # " + "\n    # ".join(lines)
             else:
                 # This is a message, enum, service, or method
                 if len(lines) == 1 and len(lines[0]) < 70:
@@ -146,6 +175,9 @@ def generate_code(request, response):
     output_map = {}
     for proto_file in request.proto_file:
         out = proto_file.package
+        if out == "google.protobuf":
+            continue
+
         if not out:
             out = os.path.splitext(proto_file.name)[0].replace(os.path.sep, ".")
 
@@ -163,6 +195,7 @@ def generate_code(request, response):
             "package": package,
             "files": [f.name for f in options["files"]],
             "imports": set(),
+            "datetime_imports": set(),
             "typing_imports": set(),
             "messages": [],
             "enums": [],
@@ -179,7 +212,7 @@ def generate_code(request, response):
             for item, path in traverse(proto_file):
                 # print(item, file=sys.stderr)
                 # print(path, file=sys.stderr)
-                data = {"name": item.name}
+                data = {"name": item.name, "py_name": stringcase.pascalcase(item.name)}
 
                 if isinstance(item, DescriptorProto):
                     # print(item, file=sys.stderr)
@@ -203,6 +236,14 @@ def generate_code(request, response):
                         packed = False
 
                         field_type = f.Type.Name(f.type).lower()[5:]
+
+                        field_wraps = ""
+                        if f.type_name.startswith(
+                            ".google.protobuf"
+                        ) and f.type_name.endswith("Value"):
+                            w = f.type_name.split(".").pop()[:-5].upper()
+                            field_wraps = f"betterproto.TYPE_{w}"
+
                         map_types = None
                         if f.type == 11:
                             # This might be a map...
@@ -252,13 +293,23 @@ def generate_code(request, response):
                         if f.HasField("oneof_index"):
                             one_of = item.oneof_decl[f.oneof_index].name
 
+                        if "Optional[" in t:
+                            output["typing_imports"].add("Optional")
+
+                        if "timedelta" in t:
+                            output["datetime_imports"].add("timedelta")
+                        elif "datetime" in t:
+                            output["datetime_imports"].add("datetime")
+
                         data["properties"].append(
                             {
                                 "name": f.name,
+                                "py_name": safe_snake_case(f.name),
                                 "number": f.number,
                                 "comment": get_comment(proto_file, path + [2, i]),
                                 "proto_type": int(f.type),
                                 "field_type": field_type,
+                                "field_wraps": field_wraps,
                                 "map_types": map_types,
                                 "type": t,
                                 "zero": zero,
@@ -294,6 +345,7 @@ def generate_code(request, response):
 
                 data = {
                     "name": service.name,
+                    "py_name": stringcase.pascalcase(service.name),
                     "comment": get_comment(proto_file, [6, i]),
                     "methods": [],
                 }
@@ -317,7 +369,7 @@ def generate_code(request, response):
                     data["methods"].append(
                         {
                             "name": method.name,
-                            "py_name": snake_case(method.name),
+                            "py_name": stringcase.snakecase(method.name),
                             "comment": get_comment(proto_file, [6, i, 2, j]),
                             "route": f"/{package}.{service.name}/{method.name}",
                             "input": get_ref_type(
@@ -338,6 +390,7 @@ def generate_code(request, response):
                 output["services"].append(data)
 
         output["imports"] = sorted(output["imports"])
+        output["datetime_imports"] = sorted(output["datetime_imports"])
         output["typing_imports"] = sorted(output["typing_imports"])
 
         # Fill response
@@ -361,10 +414,20 @@ def generate_code(request, response):
                 inits.add(base)
 
     for base in inits:
+        name = os.path.join(base, "__init__.py")
+
+        if os.path.exists(name):
+            # Never overwrite inits as they may have custom stuff in them.
+            continue
+
         init = response.file.add()
-        init.name = os.path.join(base, "__init__.py")
+        init.name = name
         init.content = b""
 
+    filenames = sorted([f.name for f in response.file])
+    for fname in filenames:
+        print(f"Writing {fname}", file=sys.stderr)
+
 
 def main():
     """The plugin's main entry point."""

betterproto/templates/template.py

@@ -2,6 +2,10 @@
 # sources: {{ ', '.join(description.files) }}
 # plugin: python-betterproto
 from dataclasses import dataclass
+{% if description.datetime_imports %}
+from datetime import {% for i in description.datetime_imports %}{{ i }}{% if not loop.last %}, {% endif %}{% endfor %}
+
+{% endif%}
 {% if description.typing_imports %}
 from typing import {% for i in description.typing_imports %}{{ i }}{% if not loop.last %}, {% endif %}{% endfor %}
 
@@ -18,7 +22,7 @@ import grpclib
 
 
 {% if description.enums %}{% for enum in description.enums %}
-class {{ enum.name }}(betterproto.Enum):
+class {{ enum.py_name }}(betterproto.Enum):
     {% if enum.comment %}
 {{ enum.comment }}
 
@@ -35,7 +39,7 @@ class {{ enum.name }}(betterproto.Enum):
 {% endif %}
 {% for message in description.messages %}
 @dataclass
-class {{ message.name }}(betterproto.Message):
+class {{ message.py_name }}(betterproto.Message):
     {% if message.comment %}
 {{ message.comment }}
 
@@ -44,7 +48,7 @@ class {{ message.name }}(betterproto.Message):
         {% if field.comment %}
 {{ field.comment }}
         {% endif %}
-    {{ field.name }}: {{ field.type }} = betterproto.{{ field.field_type }}_field({{ field.number }}{% if field.field_type == 'map'%}, betterproto.{{ field.map_types[0] }}, betterproto.{{ field.map_types[1] }}{% endif %}{% if field.one_of %}, group="{{ field.one_of }}"{% endif %})
+    {{ field.py_name }}: {{ field.type }} = betterproto.{{ field.field_type }}_field({{ field.number }}{% if field.field_type == 'map'%}, betterproto.{{ field.map_types[0] }}, betterproto.{{ field.map_types[1] }}{% endif %}{% if field.one_of %}, group="{{ field.one_of }}"{% endif %}{% if field.field_wraps %}, wraps={{ field.field_wraps }}{% endif %})
     {% endfor %}
     {% if not message.properties %}
     pass
@@ -53,13 +57,13 @@ class {{ message.name }}(betterproto.Message):
 
 {% endfor %}
 {% for service in description.services %}
-class {{ service.name }}Stub(betterproto.ServiceStub):
+class {{ service.py_name }}Stub(betterproto.ServiceStub):
     {% if service.comment %}
 {{ service.comment }}
 
     {% endif %}
     {% for method in service.methods %}
-    async def {{ method.py_name }}(self{% if method.input_message and method.input_message.properties %}, *, {% for field in method.input_message.properties %}{{ field.name }}: {% if field.zero == "None" %}Optional[{{ field.type }}]{% else %}{{ field.type }}{% endif %} = {{ field.zero }}{% if not loop.last %}, {% endif %}{% endfor %}{% endif %}) -> {% if method.server_streaming %}AsyncGenerator[{{ method.output }}, None]{% else %}{{ method.output }}{% endif %}:
+    async def {{ method.py_name }}(self{% if method.input_message and method.input_message.properties %}, *, {% for field in method.input_message.properties %}{{ field.name }}: {% if field.zero == "None" and not field.type.startswith("Optional[") %}Optional[{{ field.type }}]{% else %}{{ field.type }}{% endif %} = {{ field.zero }}{% if not loop.last %}, {% endif %}{% endfor %}{% endif %}) -> {% if method.server_streaming %}AsyncGenerator[{{ method.output }}, None]{% else %}{{ method.output }}{% endif %}:
         {% if method.comment %}
 {{ method.comment }}
 

betterproto/tests/bool.json

@@ -0,0 +1,3 @@
+{
+  "value": true
+}

betterproto/tests/bool.proto

@@ -0,0 +1,5 @@
+syntax = "proto3";
+
+message Test {
+    bool value = 1;
+}

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/googletypes-missing.json

@@ -0,0 +1 @@
+{}

betterproto/tests/googletypes.json

@@ -0,0 +1,5 @@
+{
+  "maybe": false,
+  "ts": "1972-01-01T10:00:20.021Z",
+  "duration": "1.200s"
+}

betterproto/tests/googletypes.proto

@@ -0,0 +1,12 @@
+syntax = "proto3";
+
+import "google/protobuf/duration.proto";
+import "google/protobuf/timestamp.proto";
+import "google/protobuf/wrappers.proto";
+
+message Test {
+  google.protobuf.BoolValue maybe = 1;
+  google.protobuf.Timestamp ts = 2;
+  google.protobuf.Duration duration = 3;
+  google.protobuf.Int32Value important = 4;
+}

betterproto/tests/keywords.json

@@ -0,0 +1,5 @@
+{
+  "for": 1,
+  "with": 2,
+  "as": 3
+}

betterproto/tests/keywords.proto

@@ -0,0 +1,7 @@
+syntax = "proto3";
+
+message Test {
+  int32 for = 1;
+  int32 with = 2;
+  int32 as = 3;
+}

betterproto/tests/test_features.py

@@ -1,5 +1,6 @@
 import betterproto
 from dataclasses import dataclass
+from typing import Optional
 
 
 def test_has_field():
@@ -115,3 +116,49 @@ 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,
+    }
+
+
+def test_optional_flag():
+    @dataclass
+    class Request(betterproto.Message):
+        flag: Optional[bool] = betterproto.message_field(1, wraps=betterproto.TYPE_BOOL)
+
+    # Serialization of not passed vs. set vs. zero-value.
+    assert bytes(Request()) == b""
+    assert bytes(Request(flag=True)) == b"\n\x02\x08\x01"
+    assert bytes(Request(flag=False)) == b"\n\x00"
+
+    # Differentiate between not passed and the zero-value.
+    assert Request().parse(b"").flag == None
+    assert Request().parse(b"\n\x00").flag == False

setup.py

@@ -2,7 +2,7 @@ from setuptools import setup, find_packages
 
 setup(
     name="betterproto",
-    version="1.0.1",
+    version="1.1.0",
     description="A better Protobuf / gRPC generator & library",
     long_description=open("README.md", "r").read(),
     long_description_content_type="text/markdown",
@@ -18,7 +18,7 @@ setup(
     ),
     package_data={"betterproto": ["py.typed", "templates/template.py"]},
     python_requires=">=3.7",
-    install_requires=["grpclib"],
+    install_requires=["grpclib", "stringcase"],
     extras_require={"compiler": ["jinja2", "protobuf"]},
     zip_safe=False,
 )