Python: add datetime support + pass mypy --strict + rename JSON-related methods (#14)

* Python: add datetime support + pass mypy --strict

* Fix rfc3339 regex

Author: ucarion

crates/target_csharp_system_text/src/lib.rs

@@ -160,9 +160,7 @@ impl jtd_codegen::target::Target for Target {
                 None
             }
 
-            target::Item::Postamble => {
-                None
-            }
+            target::Item::Postamble => None,
 
             target::Item::Alias {
                 metadata,

crates/target_go/src/lib.rs

@@ -157,9 +157,7 @@ impl jtd_codegen::target::Target for Target {
                 None
             }
 
-            target::Item::Postamble => {
-                None
-            }
+            target::Item::Postamble => None,
 
             target::Item::Alias {
                 metadata,

crates/target_java_jackson/src/lib.rs

@@ -198,9 +198,7 @@ impl jtd_codegen::target::Target for Target {
                 None
             }
 
-            target::Item::Postamble => {
-                None
-            }
+            target::Item::Postamble => None,
 
             target::Item::Alias {
                 metadata,

crates/target_python/docker/Dockerfile

@@ -2,10 +2,14 @@ FROM python:3.9
 
 ARG MAIN
 
+RUN pip3 install mypy
+
 WORKDIR /work
 COPY /main.py /work/main.py
 
 COPY /gen /work/gen
 RUN sed -i -e "s/MAIN/$MAIN/g" /work/main.py
 
+RUN mypy --strict .
+
 ENTRYPOINT python3 -u main.py

crates/target_python/docker/main.py

@@ -3,5 +3,5 @@
 from gen import MAIN
 
 for line in sys.stdin:
-    value = MAIN.from_json(json.loads(line))
-    print(json.dumps(value.to_json()))
+    value = MAIN.from_json_data(json.loads(line))
+    print(json.dumps(value.to_json_data()))

crates/target_python/output/basic_discriminator/__init__.py

@@ -1,70 +1,114 @@
 # Code generated by jtd-codegen for Python v0.2.0
 
+import re
 from dataclasses import dataclass
-from typing import Any, Union, get_args, get_origin
+from datetime import datetime, timedelta, timezone
+from typing import Any, Dict, Type, Union, get_args, get_origin
 
-def _from_json(cls, data):
-    if data is None or cls in [bool, int, float, str, object] or cls is Any:
-        return data
-    if get_origin(cls) is Union:
-        return _from_json(get_args(cls)[0], data)
-    if get_origin(cls) is list:
-        return [_from_json(get_args(cls)[0], d) for d in data]
-    if get_origin(cls) is dict:
-        return { k: _from_json(get_args(cls)[1], v) for k, v in data.items() }
-    return cls.from_json(data)
-
-def _to_json(data):
-    if data is None or type(data) in [bool, int, float, str, object]:
-        return data
-    if type(data) is list:
-        return [_to_json(d) for d in data]
-    if type(data) is dict:
-        return { k: _to_json(v) for k, v in data.items() }
-    return data.to_json()
 
 @dataclass
 class Root:
     foo: 'str'
 
     @classmethod
-    def from_json(cls, data) -> 'Root':
-        return {
+    def from_json_data(cls, data: Any) -> 'Root':
+        variants: Dict[str, Type[Root]] = {
             "BAR_BAZ": RootBarBaz,
             "QUUX": RootQuux,
-        }[data["foo"]].from_json(data)
+        }
 
-    def to_json(self):
+        return variants[data["foo"]].from_json_data(data)
+
+    def to_json_data(self) -> Any:
         pass
 
 @dataclass
 class RootBarBaz(Root):
     baz: 'str'
 
     @classmethod
-    def from_json(cls, data) -> 'RootBarBaz':
+    def from_json_data(cls, data: Any) -> 'RootBarBaz':
         return cls(
             "BAR_BAZ",
-            _from_json(str, data.get("baz")),
+            _from_json_data(str, data.get("baz")),
         )
 
-    def to_json(self):
+    def to_json_data(self) -> Any:
         data = { "foo": "BAR_BAZ" }
-        data["baz"] = _to_json(self.baz)
+        data["baz"] = _to_json_data(self.baz)
         return data
 
 @dataclass
 class RootQuux(Root):
     quuz: 'str'
 
     @classmethod
-    def from_json(cls, data) -> 'RootQuux':
+    def from_json_data(cls, data: Any) -> 'RootQuux':
         return cls(
             "QUUX",
-            _from_json(str, data.get("quuz")),
+            _from_json_data(str, data.get("quuz")),
         )
 
-    def to_json(self):
+    def to_json_data(self) -> Any:
         data = { "foo": "QUUX" }
-        data["quuz"] = _to_json(self.quuz)
+        data["quuz"] = _to_json_data(self.quuz)
+        return data
+
+def _from_json_data(cls: Any, data: Any) -> Any:
+    if data is None or cls in [bool, int, float, str, object] or cls is Any:
+        return data
+    if cls is datetime:
+        return _parse_rfc3339(data)
+    if get_origin(cls) is Union:
+        return _from_json_data(get_args(cls)[0], data)
+    if get_origin(cls) is list:
+        return [_from_json_data(get_args(cls)[0], d) for d in data]
+    if get_origin(cls) is dict:
+        return { k: _from_json_data(get_args(cls)[1], v) for k, v in data.items() }
+    return cls.from_json_data(data)
+
+def _to_json_data(data: Any) -> Any:
+    if data is None or type(data) in [bool, int, float, str, object]:
         return data
+    if type(data) is datetime:
+        return data.isoformat()
+    if type(data) is list:
+        return [_to_json_data(d) for d in data]
+    if type(data) is dict:
+        return { k: _to_json_data(v) for k, v in data.items() }
+    return data.to_json_data()
+
+def _parse_rfc3339(s: str) -> datetime:
+    datetime_re = '^(\d{4})-(\d{2})-(\d{2})[tT](\d{2}):(\d{2}):(\d{2})(\.\d+)?([zZ]|((\+|-)(\d{2}):(\d{2})))$'
+    match = re.match(datetime_re, s)
+    if not match:
+        raise ValueError('Invalid RFC3339 date/time', s)
+
+    (year, month, day, hour, minute, second, frac_seconds, offset,
+     *tz) = match.groups()
+
+    frac_seconds_parsed = None
+    if frac_seconds:
+        frac_seconds_parsed = int(float(frac_seconds) * 1_000_000)
+    else:
+        frac_seconds_parsed = 0
+
+    tzinfo = None
+    if offset == 'Z':
+        tzinfo = timezone.utc
+    else:
+        hours = int(tz[2])
+        minutes = int(tz[3])
+        sign = 1 if tz[1] == '+' else -1
+
+        if minutes not in range(60):
+            raise ValueError('minute offset must be in 0..59')
+
+        tzinfo = timezone(timedelta(minutes=sign * (60 * hours + minutes)))
+
+    second_parsed = int(second)
+    if second_parsed == 60:
+        second_parsed = 59
+
+    return datetime(int(year), int(month), int(day), int(hour), int(minute),
+                    second_parsed, frac_seconds_parsed, tzinfo)            

crates/target_python/output/basic_enum/__init__.py

@@ -1,35 +1,77 @@
 # Code generated by jtd-codegen for Python v0.2.0
 
+import re
+from datetime import datetime, timedelta, timezone
 from enum import Enum
 from typing import Any, Union, get_args, get_origin
 
-def _from_json(cls, data):
+
+class Root(Enum):
+    BAR = "Bar"
+    BAZ = "Baz"
+    FOO = "Foo"
+    @classmethod
+    def from_json_data(cls, data: Any) -> 'Root':
+        return cls(data)
+
+    def to_json_data(self) -> Any:
+        return self.value
+
+def _from_json_data(cls: Any, data: Any) -> Any:
     if data is None or cls in [bool, int, float, str, object] or cls is Any:
         return data
+    if cls is datetime:
+        return _parse_rfc3339(data)
     if get_origin(cls) is Union:
-        return _from_json(get_args(cls)[0], data)
+        return _from_json_data(get_args(cls)[0], data)
     if get_origin(cls) is list:
-        return [_from_json(get_args(cls)[0], d) for d in data]
+        return [_from_json_data(get_args(cls)[0], d) for d in data]
     if get_origin(cls) is dict:
-        return { k: _from_json(get_args(cls)[1], v) for k, v in data.items() }
-    return cls.from_json(data)
+        return { k: _from_json_data(get_args(cls)[1], v) for k, v in data.items() }
+    return cls.from_json_data(data)
 
-def _to_json(data):
+def _to_json_data(data: Any) -> Any:
     if data is None or type(data) in [bool, int, float, str, object]:
         return data
+    if type(data) is datetime:
+        return data.isoformat()
     if type(data) is list:
-        return [_to_json(d) for d in data]
+        return [_to_json_data(d) for d in data]
     if type(data) is dict:
-        return { k: _to_json(v) for k, v in data.items() }
-    return data.to_json()
+        return { k: _to_json_data(v) for k, v in data.items() }
+    return data.to_json_data()
 
-class Root(Enum):
-    BAR = "Bar"
-    BAZ = "Baz"
-    FOO = "Foo"
-    @classmethod
-    def from_json(cls, data) -> 'Root':
-        return cls(data)
+def _parse_rfc3339(s: str) -> datetime:
+    datetime_re = '^(\d{4})-(\d{2})-(\d{2})[tT](\d{2}):(\d{2}):(\d{2})(\.\d+)?([zZ]|((\+|-)(\d{2}):(\d{2})))$'
+    match = re.match(datetime_re, s)
+    if not match:
+        raise ValueError('Invalid RFC3339 date/time', s)
 
-    def to_json(self):
-        return self.value
+    (year, month, day, hour, minute, second, frac_seconds, offset,
+     *tz) = match.groups()
+
+    frac_seconds_parsed = None
+    if frac_seconds:
+        frac_seconds_parsed = int(float(frac_seconds) * 1_000_000)
+    else:
+        frac_seconds_parsed = 0
+
+    tzinfo = None
+    if offset == 'Z':
+        tzinfo = timezone.utc
+    else:
+        hours = int(tz[2])
+        minutes = int(tz[3])
+        sign = 1 if tz[1] == '+' else -1
+
+        if minutes not in range(60):
+            raise ValueError('minute offset must be in 0..59')
+
+        tzinfo = timezone(timedelta(minutes=sign * (60 * hours + minutes)))
+
+    second_parsed = int(second)
+    if second_parsed == 60:
+        second_parsed = 59
+
+    return datetime(int(year), int(month), int(day), int(hour), int(minute),
+                    second_parsed, frac_seconds_parsed, tzinfo)