This commit is contained in:
Iliyan Angelov
2025-12-01 06:50:10 +02:00
parent 91f51bc6fe
commit 62c1fe5951
4682 changed files with 544807 additions and 31208 deletions

View File

@@ -1,13 +1,14 @@
"""This module contains related classes and functions for serialization."""
from __future__ import annotations
import dataclasses
from functools import partialmethod
from typing import TYPE_CHECKING, Any, Callable, TypeVar, Union, overload
from functools import partial, partialmethod
from typing import TYPE_CHECKING, Annotated, Any, Callable, Literal, TypeVar, overload
from pydantic_core import PydanticUndefined, core_schema
from pydantic_core import core_schema as _core_schema
from typing_extensions import Annotated, Literal, TypeAlias
from pydantic_core.core_schema import SerializationInfo, SerializerFunctionWrapHandler, WhenUsed
from typing_extensions import TypeAlias
from . import PydanticUndefinedAnnotation
from ._internal import _decorators, _internal_dataclass
@@ -18,6 +19,26 @@ from .annotated_handlers import GetCoreSchemaHandler
class PlainSerializer:
"""Plain serializers use a function to modify the output of serialization.
This is particularly helpful when you want to customize the serialization for annotated types.
Consider an input of `list`, which will be serialized into a space-delimited string.
```python
from typing import Annotated
from pydantic import BaseModel, PlainSerializer
CustomStr = Annotated[
list, PlainSerializer(lambda x: ' '.join(x), return_type=str)
]
class StudentModel(BaseModel):
courses: CustomStr
student = StudentModel(courses=['Math', 'Chemistry', 'English'])
print(student.model_dump())
#> {'courses': 'Math Chemistry English'}
```
Attributes:
func: The serializer function.
return_type: The return type for the function. If omitted it will be inferred from the type annotation.
@@ -27,7 +48,7 @@ class PlainSerializer:
func: core_schema.SerializerFunction
return_type: Any = PydanticUndefined
when_used: Literal['always', 'unless-none', 'json', 'json-unless-none'] = 'always'
when_used: WhenUsed = 'always'
def __get_pydantic_core_schema__(self, source_type: Any, handler: GetCoreSchemaHandler) -> core_schema.CoreSchema:
"""Gets the Pydantic core schema.
@@ -40,12 +61,20 @@ class PlainSerializer:
The Pydantic core schema.
"""
schema = handler(source_type)
try:
return_type = _decorators.get_function_return_type(
self.func, self.return_type, handler._get_types_namespace()
)
except NameError as e:
raise PydanticUndefinedAnnotation.from_name_error(e) from e
if self.return_type is not PydanticUndefined:
return_type = self.return_type
else:
try:
# Do not pass in globals as the function could be defined in a different module.
# Instead, let `get_callable_return_type` infer the globals to use, but still pass
# in locals that may contain a parent/rebuild namespace:
return_type = _decorators.get_callable_return_type(
self.func,
localns=handler._get_types_namespace().locals,
)
except NameError as e:
raise PydanticUndefinedAnnotation.from_name_error(e) from e
return_schema = None if return_type is PydanticUndefined else handler.generate_schema(return_type)
schema['serialization'] = core_schema.plain_serializer_function_ser_schema(
function=self.func,
@@ -61,6 +90,58 @@ class WrapSerializer:
"""Wrap serializers receive the raw inputs along with a handler function that applies the standard serialization
logic, and can modify the resulting value before returning it as the final output of serialization.
For example, here's a scenario in which a wrap serializer transforms timezones to UTC **and** utilizes the existing `datetime` serialization logic.
```python
from datetime import datetime, timezone
from typing import Annotated, Any
from pydantic import BaseModel, WrapSerializer
class EventDatetime(BaseModel):
start: datetime
end: datetime
def convert_to_utc(value: Any, handler, info) -> dict[str, datetime]:
# Note that `handler` can actually help serialize the `value` for
# further custom serialization in case it's a subclass.
partial_result = handler(value, info)
if info.mode == 'json':
return {
k: datetime.fromisoformat(v).astimezone(timezone.utc)
for k, v in partial_result.items()
}
return {k: v.astimezone(timezone.utc) for k, v in partial_result.items()}
UTCEventDatetime = Annotated[EventDatetime, WrapSerializer(convert_to_utc)]
class EventModel(BaseModel):
event_datetime: UTCEventDatetime
dt = EventDatetime(
start='2024-01-01T07:00:00-08:00', end='2024-01-03T20:00:00+06:00'
)
event = EventModel(event_datetime=dt)
print(event.model_dump())
'''
{
'event_datetime': {
'start': datetime.datetime(
2024, 1, 1, 15, 0, tzinfo=datetime.timezone.utc
),
'end': datetime.datetime(
2024, 1, 3, 14, 0, tzinfo=datetime.timezone.utc
),
}
}
'''
print(event.model_dump_json())
'''
{"event_datetime":{"start":"2024-01-01T15:00:00Z","end":"2024-01-03T14:00:00Z"}}
'''
```
Attributes:
func: The serializer function to be wrapped.
return_type: The return type for the function. If omitted it will be inferred from the type annotation.
@@ -70,7 +151,7 @@ class WrapSerializer:
func: core_schema.WrapSerializerFunction
return_type: Any = PydanticUndefined
when_used: Literal['always', 'unless-none', 'json', 'json-unless-none'] = 'always'
when_used: WhenUsed = 'always'
def __get_pydantic_core_schema__(self, source_type: Any, handler: GetCoreSchemaHandler) -> core_schema.CoreSchema:
"""This method is used to get the Pydantic core schema of the class.
@@ -83,12 +164,20 @@ class WrapSerializer:
The generated core schema of the class.
"""
schema = handler(source_type)
try:
return_type = _decorators.get_function_return_type(
self.func, self.return_type, handler._get_types_namespace()
)
except NameError as e:
raise PydanticUndefinedAnnotation.from_name_error(e) from e
if self.return_type is not PydanticUndefined:
return_type = self.return_type
else:
try:
# Do not pass in globals as the function could be defined in a different module.
# Instead, let `get_callable_return_type` infer the globals to use, but still pass
# in locals that may contain a parent/rebuild namespace:
return_type = _decorators.get_callable_return_type(
self.func,
localns=handler._get_types_namespace().locals,
)
except NameError as e:
raise PydanticUndefinedAnnotation.from_name_error(e) from e
return_schema = None if return_type is PydanticUndefined else handler.generate_schema(return_type)
schema['serialization'] = core_schema.wrap_serializer_function_ser_schema(
function=self.func,
@@ -100,58 +189,77 @@ class WrapSerializer:
if TYPE_CHECKING:
_PartialClsOrStaticMethod: TypeAlias = Union[classmethod[Any, Any, Any], staticmethod[Any, Any], partialmethod[Any]]
_PlainSerializationFunction = Union[_core_schema.SerializerFunction, _PartialClsOrStaticMethod]
_WrapSerializationFunction = Union[_core_schema.WrapSerializerFunction, _PartialClsOrStaticMethod]
_PlainSerializeMethodType = TypeVar('_PlainSerializeMethodType', bound=_PlainSerializationFunction)
_WrapSerializeMethodType = TypeVar('_WrapSerializeMethodType', bound=_WrapSerializationFunction)
_Partial: TypeAlias = 'partial[Any] | partialmethod[Any]'
FieldPlainSerializer: TypeAlias = 'core_schema.SerializerFunction | _Partial'
"""A field serializer method or function in `plain` mode."""
FieldWrapSerializer: TypeAlias = 'core_schema.WrapSerializerFunction | _Partial'
"""A field serializer method or function in `wrap` mode."""
FieldSerializer: TypeAlias = 'FieldPlainSerializer | FieldWrapSerializer'
"""A field serializer method or function."""
_FieldPlainSerializerT = TypeVar('_FieldPlainSerializerT', bound=FieldPlainSerializer)
_FieldWrapSerializerT = TypeVar('_FieldWrapSerializerT', bound=FieldWrapSerializer)
@overload
def field_serializer(
__field: str,
*fields: str,
return_type: Any = ...,
when_used: Literal['always', 'unless-none', 'json', 'json-unless-none'] = ...,
check_fields: bool | None = ...,
) -> Callable[[_PlainSerializeMethodType], _PlainSerializeMethodType]:
...
@overload
def field_serializer(
__field: str,
*fields: str,
mode: Literal['plain'],
return_type: Any = ...,
when_used: Literal['always', 'unless-none', 'json', 'json-unless-none'] = ...,
check_fields: bool | None = ...,
) -> Callable[[_PlainSerializeMethodType], _PlainSerializeMethodType]:
...
@overload
def field_serializer(
__field: str,
field: str,
/,
*fields: str,
mode: Literal['wrap'],
return_type: Any = ...,
when_used: Literal['always', 'unless-none', 'json', 'json-unless-none'] = ...,
when_used: WhenUsed = ...,
check_fields: bool | None = ...,
) -> Callable[[_WrapSerializeMethodType], _WrapSerializeMethodType]:
...
) -> Callable[[_FieldWrapSerializerT], _FieldWrapSerializerT]: ...
@overload
def field_serializer(
field: str,
/,
*fields: str,
mode: Literal['plain'] = ...,
return_type: Any = ...,
when_used: WhenUsed = ...,
check_fields: bool | None = ...,
) -> Callable[[_FieldPlainSerializerT], _FieldPlainSerializerT]: ...
def field_serializer(
*fields: str,
mode: Literal['plain', 'wrap'] = 'plain',
# TODO PEP 747 (grep for 'return_type' on the whole code base):
return_type: Any = PydanticUndefined,
when_used: Literal['always', 'unless-none', 'json', 'json-unless-none'] = 'always',
when_used: WhenUsed = 'always',
check_fields: bool | None = None,
) -> Callable[[Any], Any]:
) -> (
Callable[[_FieldWrapSerializerT], _FieldWrapSerializerT]
| Callable[[_FieldPlainSerializerT], _FieldPlainSerializerT]
):
"""Decorator that enables custom field serialization.
See [Custom serializers](../concepts/serialization.md#custom-serializers) for more information.
In the below example, a field of type `set` is used to mitigate duplication. A `field_serializer` is used to serialize the data as a sorted list.
```python
from pydantic import BaseModel, field_serializer
class StudentModel(BaseModel):
name: str = 'Jane'
courses: set[str]
@field_serializer('courses', when_used='json')
def serialize_courses_in_order(self, courses: set[str]):
return sorted(courses)
student = StudentModel(courses={'Math', 'Chemistry', 'English'})
print(student.model_dump_json())
#> {"name":"Jane","courses":["Chemistry","English","Math"]}
```
See [the usage documentation](../concepts/serialization.md#serializers) for more information.
Four signatures are supported:
@@ -175,9 +283,7 @@ def field_serializer(
The decorator function.
"""
def dec(
f: Callable[..., Any] | staticmethod[Any, Any] | classmethod[Any, Any, Any]
) -> _decorators.PydanticDescriptorProxy[Any]:
def dec(f: FieldSerializer) -> _decorators.PydanticDescriptorProxy[Any]:
dec_info = _decorators.FieldSerializerDecoratorInfo(
fields=fields,
mode=mode,
@@ -185,42 +291,109 @@ def field_serializer(
when_used=when_used,
check_fields=check_fields,
)
return _decorators.PydanticDescriptorProxy(f, dec_info)
return _decorators.PydanticDescriptorProxy(f, dec_info) # pyright: ignore[reportArgumentType]
return dec
return dec # pyright: ignore[reportReturnType]
FuncType = TypeVar('FuncType', bound=Callable[..., Any])
if TYPE_CHECKING:
# The first argument in the following callables represent the `self` type:
ModelPlainSerializerWithInfo: TypeAlias = Callable[[Any, SerializationInfo[Any]], Any]
"""A model serializer method with the `info` argument, in `plain` mode."""
ModelPlainSerializerWithoutInfo: TypeAlias = Callable[[Any], Any]
"""A model serializer method without the `info` argument, in `plain` mode."""
ModelPlainSerializer: TypeAlias = 'ModelPlainSerializerWithInfo | ModelPlainSerializerWithoutInfo'
"""A model serializer method in `plain` mode."""
ModelWrapSerializerWithInfo: TypeAlias = Callable[[Any, SerializerFunctionWrapHandler, SerializationInfo[Any]], Any]
"""A model serializer method with the `info` argument, in `wrap` mode."""
ModelWrapSerializerWithoutInfo: TypeAlias = Callable[[Any, SerializerFunctionWrapHandler], Any]
"""A model serializer method without the `info` argument, in `wrap` mode."""
ModelWrapSerializer: TypeAlias = 'ModelWrapSerializerWithInfo | ModelWrapSerializerWithoutInfo'
"""A model serializer method in `wrap` mode."""
ModelSerializer: TypeAlias = 'ModelPlainSerializer | ModelWrapSerializer'
_ModelPlainSerializerT = TypeVar('_ModelPlainSerializerT', bound=ModelPlainSerializer)
_ModelWrapSerializerT = TypeVar('_ModelWrapSerializerT', bound=ModelWrapSerializer)
@overload
def model_serializer(__f: FuncType) -> FuncType:
...
def model_serializer(f: _ModelPlainSerializerT, /) -> _ModelPlainSerializerT: ...
@overload
def model_serializer(
*, mode: Literal['wrap'], when_used: WhenUsed = 'always', return_type: Any = ...
) -> Callable[[_ModelWrapSerializerT], _ModelWrapSerializerT]: ...
@overload
def model_serializer(
*,
mode: Literal['plain', 'wrap'] = ...,
when_used: Literal['always', 'unless-none', 'json', 'json-unless-none'] = 'always',
mode: Literal['plain'] = ...,
when_used: WhenUsed = 'always',
return_type: Any = ...,
) -> Callable[[FuncType], FuncType]:
...
) -> Callable[[_ModelPlainSerializerT], _ModelPlainSerializerT]: ...
def model_serializer(
__f: Callable[..., Any] | None = None,
f: _ModelPlainSerializerT | _ModelWrapSerializerT | None = None,
/,
*,
mode: Literal['plain', 'wrap'] = 'plain',
when_used: Literal['always', 'unless-none', 'json', 'json-unless-none'] = 'always',
when_used: WhenUsed = 'always',
return_type: Any = PydanticUndefined,
) -> Callable[[Any], Any]:
) -> (
_ModelPlainSerializerT
| Callable[[_ModelWrapSerializerT], _ModelWrapSerializerT]
| Callable[[_ModelPlainSerializerT], _ModelPlainSerializerT]
):
"""Decorator that enables custom model serialization.
See [Custom serializers](../concepts/serialization.md#custom-serializers) for more information.
This is useful when a model need to be serialized in a customized manner, allowing for flexibility beyond just specific fields.
An example would be to serialize temperature to the same temperature scale, such as degrees Celsius.
```python
from typing import Literal
from pydantic import BaseModel, model_serializer
class TemperatureModel(BaseModel):
unit: Literal['C', 'F']
value: int
@model_serializer()
def serialize_model(self):
if self.unit == 'F':
return {'unit': 'C', 'value': int((self.value - 32) / 1.8)}
return {'unit': self.unit, 'value': self.value}
temperature = TemperatureModel(unit='F', value=212)
print(temperature.model_dump())
#> {'unit': 'C', 'value': 100}
```
Two signatures are supported for `mode='plain'`, which is the default:
- `(self)`
- `(self, info: SerializationInfo)`
And two other signatures for `mode='wrap'`:
- `(self, nxt: SerializerFunctionWrapHandler)`
- `(self, nxt: SerializerFunctionWrapHandler, info: SerializationInfo)`
See [the usage documentation](../concepts/serialization.md#serializers) for more information.
Args:
__f: The function to be decorated.
f: The function to be decorated.
mode: The serialization mode.
- `'plain'` means the function will be called instead of the default serialization logic
@@ -233,14 +406,14 @@ def model_serializer(
The decorator function.
"""
def dec(f: Callable[..., Any]) -> _decorators.PydanticDescriptorProxy[Any]:
def dec(f: ModelSerializer) -> _decorators.PydanticDescriptorProxy[Any]:
dec_info = _decorators.ModelSerializerDecoratorInfo(mode=mode, return_type=return_type, when_used=when_used)
return _decorators.PydanticDescriptorProxy(f, dec_info)
if __f is None:
return dec
if f is None:
return dec # pyright: ignore[reportReturnType]
else:
return dec(__f) # type: ignore
return dec(f) # pyright: ignore[reportReturnType]
AnyType = TypeVar('AnyType')
@@ -248,15 +421,19 @@ AnyType = TypeVar('AnyType')
if TYPE_CHECKING:
SerializeAsAny = Annotated[AnyType, ...] # SerializeAsAny[list[str]] will be treated by type checkers as list[str]
"""Force serialization to ignore whatever is defined in the schema and instead ask the object
itself how it should be serialized.
In particular, this means that when model subclasses are serialized, fields present in the subclass
but not in the original schema will be included.
"""Annotation used to mark a type as having duck-typing serialization behavior.
See [usage documentation](../concepts/serialization.md#serializing-with-duck-typing) for more details.
"""
else:
@dataclasses.dataclass(**_internal_dataclass.slots_true)
class SerializeAsAny: # noqa: D101
class SerializeAsAny:
"""Annotation used to mark a type as having duck-typing serialization behavior.
See [usage documentation](../concepts/serialization.md#serializing-with-duck-typing) for more details.
"""
def __class_getitem__(cls, item: Any) -> Any:
return Annotated[item, SerializeAsAny()]
@@ -268,9 +445,7 @@ else:
while schema_to_update['type'] == 'definitions':
schema_to_update = schema_to_update.copy()
schema_to_update = schema_to_update['schema']
schema_to_update['serialization'] = core_schema.wrap_serializer_function_ser_schema(
lambda x, h: h(x), schema=core_schema.any_schema()
)
schema_to_update['serialization'] = core_schema.simple_ser_schema('any')
return schema
__hash__ = object.__hash__