Update 2025-04-13_16:49:18
This commit is contained in:
@ -0,0 +1,450 @@
|
||||
"""This module contains related classes and functions for serialization."""
|
||||
|
||||
from __future__ import annotations
|
||||
|
||||
import dataclasses
|
||||
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.core_schema import SerializationInfo, SerializerFunctionWrapHandler, WhenUsed
|
||||
from typing_extensions import TypeAlias
|
||||
|
||||
from . import PydanticUndefinedAnnotation
|
||||
from ._internal import _decorators, _internal_dataclass
|
||||
from .annotated_handlers import GetCoreSchemaHandler
|
||||
|
||||
|
||||
@dataclasses.dataclass(**_internal_dataclass.slots_true, frozen=True)
|
||||
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.
|
||||
when_used: Determines when this serializer should be used. Accepts a string with values `'always'`,
|
||||
`'unless-none'`, `'json'`, and `'json-unless-none'`. Defaults to 'always'.
|
||||
"""
|
||||
|
||||
func: core_schema.SerializerFunction
|
||||
return_type: Any = PydanticUndefined
|
||||
when_used: WhenUsed = 'always'
|
||||
|
||||
def __get_pydantic_core_schema__(self, source_type: Any, handler: GetCoreSchemaHandler) -> core_schema.CoreSchema:
|
||||
"""Gets the Pydantic core schema.
|
||||
|
||||
Args:
|
||||
source_type: The source type.
|
||||
handler: The `GetCoreSchemaHandler` instance.
|
||||
|
||||
Returns:
|
||||
The Pydantic core schema.
|
||||
"""
|
||||
schema = handler(source_type)
|
||||
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,
|
||||
info_arg=_decorators.inspect_annotated_serializer(self.func, 'plain'),
|
||||
return_schema=return_schema,
|
||||
when_used=self.when_used,
|
||||
)
|
||||
return schema
|
||||
|
||||
|
||||
@dataclasses.dataclass(**_internal_dataclass.slots_true, frozen=True)
|
||||
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.
|
||||
when_used: Determines when this serializer should be used. Accepts a string with values `'always'`,
|
||||
`'unless-none'`, `'json'`, and `'json-unless-none'`. Defaults to 'always'.
|
||||
"""
|
||||
|
||||
func: core_schema.WrapSerializerFunction
|
||||
return_type: Any = PydanticUndefined
|
||||
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.
|
||||
|
||||
Args:
|
||||
source_type: Source type.
|
||||
handler: Core schema handler.
|
||||
|
||||
Returns:
|
||||
The generated core schema of the class.
|
||||
"""
|
||||
schema = handler(source_type)
|
||||
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,
|
||||
info_arg=_decorators.inspect_annotated_serializer(self.func, 'wrap'),
|
||||
return_schema=return_schema,
|
||||
when_used=self.when_used,
|
||||
)
|
||||
return schema
|
||||
|
||||
|
||||
if TYPE_CHECKING:
|
||||
_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,
|
||||
mode: Literal['wrap'],
|
||||
return_type: Any = ...,
|
||||
when_used: WhenUsed = ...,
|
||||
check_fields: bool | None = ...,
|
||||
) -> 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',
|
||||
return_type: Any = PydanticUndefined,
|
||||
when_used: WhenUsed = 'always',
|
||||
check_fields: bool | None = None,
|
||||
) -> (
|
||||
Callable[[_FieldWrapSerializerT], _FieldWrapSerializerT]
|
||||
| Callable[[_FieldPlainSerializerT], _FieldPlainSerializerT]
|
||||
):
|
||||
"""Decorator that enables custom field serialization.
|
||||
|
||||
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 typing import Set
|
||||
|
||||
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 [Custom serializers](../concepts/serialization.md#custom-serializers) for more information.
|
||||
|
||||
Four signatures are supported:
|
||||
|
||||
- `(self, value: Any, info: FieldSerializationInfo)`
|
||||
- `(self, value: Any, nxt: SerializerFunctionWrapHandler, info: FieldSerializationInfo)`
|
||||
- `(value: Any, info: SerializationInfo)`
|
||||
- `(value: Any, nxt: SerializerFunctionWrapHandler, info: SerializationInfo)`
|
||||
|
||||
Args:
|
||||
fields: Which field(s) the method should be called on.
|
||||
mode: The serialization mode.
|
||||
|
||||
- `plain` means the function will be called instead of the default serialization logic,
|
||||
- `wrap` means the function will be called with an argument to optionally call the
|
||||
default serialization logic.
|
||||
return_type: Optional return type for the function, if omitted it will be inferred from the type annotation.
|
||||
when_used: Determines the serializer will be used for serialization.
|
||||
check_fields: Whether to check that the fields actually exist on the model.
|
||||
|
||||
Returns:
|
||||
The decorator function.
|
||||
"""
|
||||
|
||||
def dec(f: FieldSerializer) -> _decorators.PydanticDescriptorProxy[Any]:
|
||||
dec_info = _decorators.FieldSerializerDecoratorInfo(
|
||||
fields=fields,
|
||||
mode=mode,
|
||||
return_type=return_type,
|
||||
when_used=when_used,
|
||||
check_fields=check_fields,
|
||||
)
|
||||
return _decorators.PydanticDescriptorProxy(f, dec_info) # pyright: ignore[reportArgumentType]
|
||||
|
||||
return dec # pyright: ignore[reportReturnType]
|
||||
|
||||
|
||||
if TYPE_CHECKING:
|
||||
# The first argument in the following callables represent the `self` type:
|
||||
|
||||
ModelPlainSerializerWithInfo: TypeAlias = Callable[[Any, SerializationInfo], 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]
|
||||
"""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: _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'] = ...,
|
||||
when_used: WhenUsed = 'always',
|
||||
return_type: Any = ...,
|
||||
) -> Callable[[_ModelPlainSerializerT], _ModelPlainSerializerT]: ...
|
||||
|
||||
|
||||
def model_serializer(
|
||||
f: _ModelPlainSerializerT | _ModelWrapSerializerT | None = None,
|
||||
/,
|
||||
*,
|
||||
mode: Literal['plain', 'wrap'] = 'plain',
|
||||
when_used: WhenUsed = 'always',
|
||||
return_type: Any = PydanticUndefined,
|
||||
) -> (
|
||||
_ModelPlainSerializerT
|
||||
| Callable[[_ModelWrapSerializerT], _ModelWrapSerializerT]
|
||||
| Callable[[_ModelPlainSerializerT], _ModelPlainSerializerT]
|
||||
):
|
||||
"""Decorator that enables custom model serialization.
|
||||
|
||||
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 [Custom serializers](../concepts/serialization.md#custom-serializers) for more information.
|
||||
|
||||
Args:
|
||||
f: The function to be decorated.
|
||||
mode: The serialization mode.
|
||||
|
||||
- `'plain'` means the function will be called instead of the default serialization logic
|
||||
- `'wrap'` means the function will be called with an argument to optionally call the default
|
||||
serialization logic.
|
||||
when_used: Determines when this serializer should be used.
|
||||
return_type: The return type for the function. If omitted it will be inferred from the type annotation.
|
||||
|
||||
Returns:
|
||||
The decorator function.
|
||||
"""
|
||||
|
||||
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 # pyright: ignore[reportReturnType]
|
||||
else:
|
||||
return dec(f) # pyright: ignore[reportReturnType]
|
||||
|
||||
|
||||
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.
|
||||
"""
|
||||
else:
|
||||
|
||||
@dataclasses.dataclass(**_internal_dataclass.slots_true)
|
||||
class SerializeAsAny: # noqa: D101
|
||||
def __class_getitem__(cls, item: Any) -> Any:
|
||||
return Annotated[item, SerializeAsAny()]
|
||||
|
||||
def __get_pydantic_core_schema__(
|
||||
self, source_type: Any, handler: GetCoreSchemaHandler
|
||||
) -> core_schema.CoreSchema:
|
||||
schema = handler(source_type)
|
||||
schema_to_update = schema
|
||||
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()
|
||||
)
|
||||
return schema
|
||||
|
||||
__hash__ = object.__hash__
|
Reference in New Issue
Block a user