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"""Configuration for Pydantic models.""" |
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from __future__ import annotations as _annotations |
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from typing import TYPE_CHECKING, Any, Callable, Dict, List, Type, TypeVar, Union |
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from typing_extensions import Literal, TypeAlias, TypedDict |
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from ._migration import getattr_migration |
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from .aliases import AliasGenerator |
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from .errors import PydanticUserError |
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if TYPE_CHECKING: |
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from ._internal._generate_schema import GenerateSchema as _GenerateSchema |
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from .fields import ComputedFieldInfo, FieldInfo |
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__all__ = ('ConfigDict', 'with_config') |
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JsonValue: TypeAlias = Union[int, float, str, bool, None, List['JsonValue'], 'JsonDict'] |
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JsonDict: TypeAlias = Dict[str, JsonValue] |
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JsonEncoder = Callable[[Any], Any] |
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JsonSchemaExtraCallable: TypeAlias = Union[ |
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Callable[[JsonDict], None], |
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Callable[[JsonDict, Type[Any]], None], |
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] |
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ExtraValues = Literal['allow', 'ignore', 'forbid'] |
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class ConfigDict(TypedDict, total=False): |
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"""A TypedDict for configuring Pydantic behaviour.""" |
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title: str | None |
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"""The title for the generated JSON schema, defaults to the model's name""" |
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model_title_generator: Callable[[type], str] | None |
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"""A callable that takes a model class and returns the title for it. Defaults to `None`.""" |
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field_title_generator: Callable[[str, FieldInfo | ComputedFieldInfo], str] | None |
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"""A callable that takes a field's name and info and returns title for it. Defaults to `None`.""" |
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str_to_lower: bool |
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"""Whether to convert all characters to lowercase for str types. Defaults to `False`.""" |
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str_to_upper: bool |
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"""Whether to convert all characters to uppercase for str types. Defaults to `False`.""" |
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str_strip_whitespace: bool |
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"""Whether to strip leading and trailing whitespace for str types.""" |
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str_min_length: int |
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"""The minimum length for str types. Defaults to `None`.""" |
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str_max_length: int | None |
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"""The maximum length for str types. Defaults to `None`.""" |
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extra: ExtraValues | None |
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""" |
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Whether to ignore, allow, or forbid extra attributes during model initialization. Defaults to `'ignore'`. |
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You can configure how pydantic handles the attributes that are not defined in the model: |
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* `allow` - Allow any extra attributes. |
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* `forbid` - Forbid any extra attributes. |
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* `ignore` - Ignore any extra attributes. |
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```py |
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from pydantic import BaseModel, ConfigDict |
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class User(BaseModel): |
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model_config = ConfigDict(extra='ignore') # (1)! |
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name: str |
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user = User(name='John Doe', age=20) # (2)! |
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print(user) |
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#> name='John Doe' |
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``` |
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1. This is the default behaviour. |
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2. The `age` argument is ignored. |
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Instead, with `extra='allow'`, the `age` argument is included: |
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```py |
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from pydantic import BaseModel, ConfigDict |
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class User(BaseModel): |
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model_config = ConfigDict(extra='allow') |
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name: str |
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user = User(name='John Doe', age=20) # (1)! |
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print(user) |
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#> name='John Doe' age=20 |
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``` |
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1. The `age` argument is included. |
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With `extra='forbid'`, an error is raised: |
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```py |
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from pydantic import BaseModel, ConfigDict, ValidationError |
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class User(BaseModel): |
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model_config = ConfigDict(extra='forbid') |
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name: str |
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try: |
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User(name='John Doe', age=20) |
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except ValidationError as e: |
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print(e) |
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''' |
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1 validation error for User |
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age |
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Extra inputs are not permitted [type=extra_forbidden, input_value=20, input_type=int] |
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''' |
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``` |
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""" |
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frozen: bool |
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""" |
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Whether models are faux-immutable, i.e. whether `__setattr__` is allowed, and also generates |
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a `__hash__()` method for the model. This makes instances of the model potentially hashable if all the |
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attributes are hashable. Defaults to `False`. |
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Note: |
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On V1, the inverse of this setting was called `allow_mutation`, and was `True` by default. |
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""" |
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populate_by_name: bool |
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""" |
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Whether an aliased field may be populated by its name as given by the model |
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attribute, as well as the alias. Defaults to `False`. |
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Note: |
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The name of this configuration setting was changed in **v2.0** from |
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`allow_population_by_field_name` to `populate_by_name`. |
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```py |
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from pydantic import BaseModel, ConfigDict, Field |
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class User(BaseModel): |
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model_config = ConfigDict(populate_by_name=True) |
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name: str = Field(alias='full_name') # (1)! |
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age: int |
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user = User(full_name='John Doe', age=20) # (2)! |
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print(user) |
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#> name='John Doe' age=20 |
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user = User(name='John Doe', age=20) # (3)! |
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print(user) |
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#> name='John Doe' age=20 |
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``` |
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1. The field `'name'` has an alias `'full_name'`. |
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2. The model is populated by the alias `'full_name'`. |
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3. The model is populated by the field name `'name'`. |
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""" |
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use_enum_values: bool |
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""" |
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Whether to populate models with the `value` property of enums, rather than the raw enum. |
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This may be useful if you want to serialize `model.model_dump()` later. Defaults to `False`. |
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!!! note |
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If you have an `Optional[Enum]` value that you set a default for, you need to use `validate_default=True` |
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for said Field to ensure that the `use_enum_values` flag takes effect on the default, as extracting an |
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enum's value occurs during validation, not serialization. |
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```py |
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from enum import Enum |
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from typing import Optional |
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from pydantic import BaseModel, ConfigDict, Field |
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class SomeEnum(Enum): |
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FOO = 'foo' |
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BAR = 'bar' |
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BAZ = 'baz' |
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class SomeModel(BaseModel): |
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model_config = ConfigDict(use_enum_values=True) |
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some_enum: SomeEnum |
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another_enum: Optional[SomeEnum] = Field(default=SomeEnum.FOO, validate_default=True) |
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model1 = SomeModel(some_enum=SomeEnum.BAR) |
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print(model1.model_dump()) |
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# {'some_enum': 'bar', 'another_enum': 'foo'} |
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model2 = SomeModel(some_enum=SomeEnum.BAR, another_enum=SomeEnum.BAZ) |
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print(model2.model_dump()) |
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#> {'some_enum': 'bar', 'another_enum': 'baz'} |
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``` |
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""" |
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validate_assignment: bool |
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""" |
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Whether to validate the data when the model is changed. Defaults to `False`. |
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The default behavior of Pydantic is to validate the data when the model is created. |
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In case the user changes the data after the model is created, the model is _not_ revalidated. |
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```py |
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from pydantic import BaseModel |
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class User(BaseModel): |
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name: str |
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user = User(name='John Doe') # (1)! |
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print(user) |
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#> name='John Doe' |
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user.name = 123 # (1)! |
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print(user) |
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#> name=123 |
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``` |
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1. The validation happens only when the model is created. |
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2. The validation does not happen when the data is changed. |
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In case you want to revalidate the model when the data is changed, you can use `validate_assignment=True`: |
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```py |
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from pydantic import BaseModel, ValidationError |
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class User(BaseModel, validate_assignment=True): # (1)! |
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name: str |
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user = User(name='John Doe') # (2)! |
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print(user) |
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#> name='John Doe' |
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try: |
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user.name = 123 # (3)! |
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except ValidationError as e: |
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print(e) |
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''' |
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1 validation error for User |
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name |
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Input should be a valid string [type=string_type, input_value=123, input_type=int] |
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''' |
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``` |
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1. You can either use class keyword arguments, or `model_config` to set `validate_assignment=True`. |
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2. The validation happens when the model is created. |
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3. The validation _also_ happens when the data is changed. |
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""" |
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arbitrary_types_allowed: bool |
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""" |
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Whether arbitrary types are allowed for field types. Defaults to `False`. |
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```py |
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from pydantic import BaseModel, ConfigDict, ValidationError |
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# This is not a pydantic model, it's an arbitrary class |
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class Pet: |
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def __init__(self, name: str): |
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self.name = name |
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class Model(BaseModel): |
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model_config = ConfigDict(arbitrary_types_allowed=True) |
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pet: Pet |
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owner: str |
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pet = Pet(name='Hedwig') |
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# A simple check of instance type is used to validate the data |
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model = Model(owner='Harry', pet=pet) |
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print(model) |
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#> pet=<__main__.Pet object at 0x0123456789ab> owner='Harry' |
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print(model.pet) |
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#> <__main__.Pet object at 0x0123456789ab> |
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print(model.pet.name) |
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#> Hedwig |
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print(type(model.pet)) |
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#> <class '__main__.Pet'> |
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try: |
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# If the value is not an instance of the type, it's invalid |
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Model(owner='Harry', pet='Hedwig') |
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except ValidationError as e: |
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print(e) |
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''' |
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1 validation error for Model |
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pet |
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Input should be an instance of Pet [type=is_instance_of, input_value='Hedwig', input_type=str] |
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''' |
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# Nothing in the instance of the arbitrary type is checked |
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# Here name probably should have been a str, but it's not validated |
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pet2 = Pet(name=42) |
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model2 = Model(owner='Harry', pet=pet2) |
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print(model2) |
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#> pet=<__main__.Pet object at 0x0123456789ab> owner='Harry' |
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print(model2.pet) |
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#> <__main__.Pet object at 0x0123456789ab> |
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print(model2.pet.name) |
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#> 42 |
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print(type(model2.pet)) |
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#> <class '__main__.Pet'> |
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``` |
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""" |
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from_attributes: bool |
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""" |
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Whether to build models and look up discriminators of tagged unions using python object attributes. |
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""" |
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loc_by_alias: bool |
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"""Whether to use the actual key provided in the data (e.g. alias) for error `loc`s rather than the field's name. Defaults to `True`.""" |
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alias_generator: Callable[[str], str] | AliasGenerator | None |
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""" |
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A callable that takes a field name and returns an alias for it |
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or an instance of [`AliasGenerator`][pydantic.aliases.AliasGenerator]. Defaults to `None`. |
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When using a callable, the alias generator is used for both validation and serialization. |
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If you want to use different alias generators for validation and serialization, you can use |
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[`AliasGenerator`][pydantic.aliases.AliasGenerator] instead. |
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If data source field names do not match your code style (e. g. CamelCase fields), |
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you can automatically generate aliases using `alias_generator`. Here's an example with |
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a basic callable: |
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```py |
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from pydantic import BaseModel, ConfigDict |
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from pydantic.alias_generators import to_pascal |
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class Voice(BaseModel): |
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model_config = ConfigDict(alias_generator=to_pascal) |
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name: str |
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language_code: str |
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voice = Voice(Name='Filiz', LanguageCode='tr-TR') |
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print(voice.language_code) |
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#> tr-TR |
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print(voice.model_dump(by_alias=True)) |
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#> {'Name': 'Filiz', 'LanguageCode': 'tr-TR'} |
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``` |
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If you want to use different alias generators for validation and serialization, you can use |
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[`AliasGenerator`][pydantic.aliases.AliasGenerator]. |
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```py |
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from pydantic import AliasGenerator, BaseModel, ConfigDict |
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from pydantic.alias_generators import to_camel, to_pascal |
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class Athlete(BaseModel): |
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first_name: str |
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last_name: str |
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sport: str |
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model_config = ConfigDict( |
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alias_generator=AliasGenerator( |
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validation_alias=to_camel, |
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serialization_alias=to_pascal, |
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) |
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) |
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athlete = Athlete(firstName='John', lastName='Doe', sport='track') |
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print(athlete.model_dump(by_alias=True)) |
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#> {'FirstName': 'John', 'LastName': 'Doe', 'Sport': 'track'} |
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``` |
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Note: |
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Pydantic offers three built-in alias generators: [`to_pascal`][pydantic.alias_generators.to_pascal], |
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[`to_camel`][pydantic.alias_generators.to_camel], and [`to_snake`][pydantic.alias_generators.to_snake]. |
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""" |
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ignored_types: tuple[type, ...] |
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"""A tuple of types that may occur as values of class attributes without annotations. This is |
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typically used for custom descriptors (classes that behave like `property`). If an attribute is set on a |
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class without an annotation and has a type that is not in this tuple (or otherwise recognized by |
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_pydantic_), an error will be raised. Defaults to `()`. |
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""" |
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allow_inf_nan: bool |
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"""Whether to allow infinity (`+inf` an `-inf`) and NaN values to float fields. Defaults to `True`.""" |
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json_schema_extra: JsonDict | JsonSchemaExtraCallable | None |
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"""A dict or callable to provide extra JSON schema properties. Defaults to `None`.""" |
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json_encoders: dict[type[object], JsonEncoder] | None |
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""" |
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A `dict` of custom JSON encoders for specific types. Defaults to `None`. |
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!!! warning "Deprecated" |
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This config option is a carryover from v1. |
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We originally planned to remove it in v2 but didn't have a 1:1 replacement so we are keeping it for now. |
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It is still deprecated and will likely be removed in the future. |
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""" |
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strict: bool |
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""" |
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_(new in V2)_ If `True`, strict validation is applied to all fields on the model. |
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By default, Pydantic attempts to coerce values to the correct type, when possible. |
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There are situations in which you may want to disable this behavior, and instead raise an error if a value's type |
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does not match the field's type annotation. |
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To configure strict mode for all fields on a model, you can set `strict=True` on the model. |
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```py |
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from pydantic import BaseModel, ConfigDict |
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class Model(BaseModel): |
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model_config = ConfigDict(strict=True) |
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name: str |
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age: int |
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``` |
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See [Strict Mode](../concepts/strict_mode.md) for more details. |
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See the [Conversion Table](../concepts/conversion_table.md) for more details on how Pydantic converts data in both |
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strict and lax modes. |
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""" |
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revalidate_instances: Literal['always', 'never', 'subclass-instances'] |
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""" |
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When and how to revalidate models and dataclasses during validation. Accepts the string |
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values of `'never'`, `'always'` and `'subclass-instances'`. Defaults to `'never'`. |
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- `'never'` will not revalidate models and dataclasses during validation |
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- `'always'` will revalidate models and dataclasses during validation |
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- `'subclass-instances'` will revalidate models and dataclasses during validation if the instance is a |
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subclass of the model or dataclass |
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By default, model and dataclass instances are not revalidated during validation. |
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```py |
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from typing import List |
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from pydantic import BaseModel |
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class User(BaseModel, revalidate_instances='never'): # (1)! |
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hobbies: List[str] |
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class SubUser(User): |
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sins: List[str] |
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class Transaction(BaseModel): |
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user: User |
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my_user = User(hobbies=['reading']) |
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t = Transaction(user=my_user) |
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print(t) |
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#> user=User(hobbies=['reading']) |
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my_user.hobbies = [1] # (2)! |
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t = Transaction(user=my_user) # (3)! |
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print(t) |
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#> user=User(hobbies=[1]) |
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my_sub_user = SubUser(hobbies=['scuba diving'], sins=['lying']) |
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t = Transaction(user=my_sub_user) |
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print(t) |
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#> user=SubUser(hobbies=['scuba diving'], sins=['lying']) |
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``` |
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1. `revalidate_instances` is set to `'never'` by **default. |
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2. The assignment is not validated, unless you set `validate_assignment` to `True` in the model's config. |
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3. Since `revalidate_instances` is set to `never`, this is not revalidated. |
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If you want to revalidate instances during validation, you can set `revalidate_instances` to `'always'` |
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in the model's config. |
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```py |
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from typing import List |
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from pydantic import BaseModel, ValidationError |
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class User(BaseModel, revalidate_instances='always'): # (1)! |
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hobbies: List[str] |
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class SubUser(User): |
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sins: List[str] |
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class Transaction(BaseModel): |
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user: User |
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my_user = User(hobbies=['reading']) |
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t = Transaction(user=my_user) |
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print(t) |
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#> user=User(hobbies=['reading']) |
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my_user.hobbies = [1] |
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try: |
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t = Transaction(user=my_user) # (2)! |
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except ValidationError as e: |
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print(e) |
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''' |
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1 validation error for Transaction |
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user.hobbies.0 |
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Input should be a valid string [type=string_type, input_value=1, input_type=int] |
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''' |
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my_sub_user = SubUser(hobbies=['scuba diving'], sins=['lying']) |
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t = Transaction(user=my_sub_user) |
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print(t) # (3)! |
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#> user=User(hobbies=['scuba diving']) |
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``` |
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1. `revalidate_instances` is set to `'always'`. |
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2. The model is revalidated, since `revalidate_instances` is set to `'always'`. |
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3. Using `'never'` we would have gotten `user=SubUser(hobbies=['scuba diving'], sins=['lying'])`. |
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It's also possible to set `revalidate_instances` to `'subclass-instances'` to only revalidate instances |
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of subclasses of the model. |
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```py |
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from typing import List |
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from pydantic import BaseModel |
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class User(BaseModel, revalidate_instances='subclass-instances'): # (1)! |
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hobbies: List[str] |
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class SubUser(User): |
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sins: List[str] |
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class Transaction(BaseModel): |
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user: User |
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my_user = User(hobbies=['reading']) |
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t = Transaction(user=my_user) |
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print(t) |
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#> user=User(hobbies=['reading']) |
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my_user.hobbies = [1] |
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t = Transaction(user=my_user) # (2)! |
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print(t) |
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#> user=User(hobbies=[1]) |
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my_sub_user = SubUser(hobbies=['scuba diving'], sins=['lying']) |
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t = Transaction(user=my_sub_user) |
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print(t) # (3)! |
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#> user=User(hobbies=['scuba diving']) |
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``` |
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1. `revalidate_instances` is set to `'subclass-instances'`. |
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2. This is not revalidated, since `my_user` is not a subclass of `User`. |
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3. Using `'never'` we would have gotten `user=SubUser(hobbies=['scuba diving'], sins=['lying'])`. |
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""" |
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ser_json_timedelta: Literal['iso8601', 'float'] |
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""" |
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The format of JSON serialized timedeltas. Accepts the string values of `'iso8601'` and |
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`'float'`. Defaults to `'iso8601'`. |
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- `'iso8601'` will serialize timedeltas to ISO 8601 durations. |
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- `'float'` will serialize timedeltas to the total number of seconds. |
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""" |
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ser_json_bytes: Literal['utf8', 'base64'] |
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""" |
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The encoding of JSON serialized bytes. Accepts the string values of `'utf8'` and `'base64'`. |
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Defaults to `'utf8'`. |
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- `'utf8'` will serialize bytes to UTF-8 strings. |
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- `'base64'` will serialize bytes to URL safe base64 strings. |
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""" |
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ser_json_inf_nan: Literal['null', 'constants', 'strings'] |
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""" |
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The encoding of JSON serialized infinity and NaN float values. Defaults to `'null'`. |
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|
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- `'null'` will serialize infinity and NaN values as `null`. |
|
- `'constants'` will serialize infinity and NaN values as `Infinity` and `NaN`. |
|
- `'strings'` will serialize infinity as string `"Infinity"` and NaN as string `"NaN"`. |
|
""" |
|
|
|
|
|
validate_default: bool |
|
"""Whether to validate default values during validation. Defaults to `False`.""" |
|
|
|
validate_return: bool |
|
"""whether to validate the return value from call validators. Defaults to `False`.""" |
|
|
|
protected_namespaces: tuple[str, ...] |
|
""" |
|
A `tuple` of strings that prevent model to have field which conflict with them. |
|
Defaults to `('model_', )`). |
|
|
|
Pydantic prevents collisions between model attributes and `BaseModel`'s own methods by |
|
namespacing them with the prefix `model_`. |
|
|
|
```py |
|
import warnings |
|
|
|
from pydantic import BaseModel |
|
|
|
warnings.filterwarnings('error') # Raise warnings as errors |
|
|
|
try: |
|
|
|
class Model(BaseModel): |
|
model_prefixed_field: str |
|
|
|
except UserWarning as e: |
|
print(e) |
|
''' |
|
Field "model_prefixed_field" has conflict with protected namespace "model_". |
|
|
|
You may be able to resolve this warning by setting `model_config['protected_namespaces'] = ()`. |
|
''' |
|
``` |
|
|
|
You can customize this behavior using the `protected_namespaces` setting: |
|
|
|
```py |
|
import warnings |
|
|
|
from pydantic import BaseModel, ConfigDict |
|
|
|
warnings.filterwarnings('error') # Raise warnings as errors |
|
|
|
try: |
|
|
|
class Model(BaseModel): |
|
model_prefixed_field: str |
|
also_protect_field: str |
|
|
|
model_config = ConfigDict( |
|
protected_namespaces=('protect_me_', 'also_protect_') |
|
) |
|
|
|
except UserWarning as e: |
|
print(e) |
|
''' |
|
Field "also_protect_field" has conflict with protected namespace "also_protect_". |
|
|
|
You may be able to resolve this warning by setting `model_config['protected_namespaces'] = ('protect_me_',)`. |
|
''' |
|
``` |
|
|
|
While Pydantic will only emit a warning when an item is in a protected namespace but does not actually have a collision, |
|
an error _is_ raised if there is an actual collision with an existing attribute: |
|
|
|
```py |
|
from pydantic import BaseModel |
|
|
|
try: |
|
|
|
class Model(BaseModel): |
|
model_validate: str |
|
|
|
except NameError as e: |
|
print(e) |
|
''' |
|
Field "model_validate" conflicts with member <bound method BaseModel.model_validate of <class 'pydantic.main.BaseModel'>> of protected namespace "model_". |
|
''' |
|
``` |
|
""" |
|
|
|
hide_input_in_errors: bool |
|
""" |
|
Whether to hide inputs when printing errors. Defaults to `False`. |
|
|
|
Pydantic shows the input value and type when it raises `ValidationError` during the validation. |
|
|
|
```py |
|
from pydantic import BaseModel, ValidationError |
|
|
|
class Model(BaseModel): |
|
a: str |
|
|
|
try: |
|
Model(a=123) |
|
except ValidationError as e: |
|
print(e) |
|
''' |
|
1 validation error for Model |
|
a |
|
Input should be a valid string [type=string_type, input_value=123, input_type=int] |
|
''' |
|
``` |
|
|
|
You can hide the input value and type by setting the `hide_input_in_errors` config to `True`. |
|
|
|
```py |
|
from pydantic import BaseModel, ConfigDict, ValidationError |
|
|
|
class Model(BaseModel): |
|
a: str |
|
model_config = ConfigDict(hide_input_in_errors=True) |
|
|
|
try: |
|
Model(a=123) |
|
except ValidationError as e: |
|
print(e) |
|
''' |
|
1 validation error for Model |
|
a |
|
Input should be a valid string [type=string_type] |
|
''' |
|
``` |
|
""" |
|
|
|
defer_build: bool |
|
""" |
|
Whether to defer model validator and serializer construction until the first model validation. Defaults to False. |
|
|
|
This can be useful to avoid the overhead of building models which are only |
|
used nested within other models, or when you want to manually define type namespace via |
|
[`Model.model_rebuild(_types_namespace=...)`][pydantic.BaseModel.model_rebuild]. |
|
|
|
See also [`experimental_defer_build_mode`][pydantic.config.ConfigDict.experimental_defer_build_mode]. |
|
|
|
!!! note |
|
`defer_build` does not work by default with FastAPI Pydantic models. By default, the validator and serializer |
|
for said models is constructed immediately for FastAPI routes. You also need to define |
|
[`experimental_defer_build_mode=('model', 'type_adapter')`][pydantic.config.ConfigDict.experimental_defer_build_mode] with FastAPI |
|
models in order for `defer_build=True` to take effect. This additional (experimental) parameter is required for |
|
the deferred building due to FastAPI relying on `TypeAdapter`s. |
|
""" |
|
|
|
experimental_defer_build_mode: tuple[Literal['model', 'type_adapter'], ...] |
|
""" |
|
Controls when [`defer_build`][pydantic.config.ConfigDict.defer_build] is applicable. Defaults to `('model',)`. |
|
|
|
Due to backwards compatibility reasons [`TypeAdapter`][pydantic.type_adapter.TypeAdapter] does not by default |
|
respect `defer_build`. Meaning when `defer_build` is `True` and `experimental_defer_build_mode` is the default `('model',)` |
|
then `TypeAdapter` immediately constructs its validator and serializer instead of postponing said construction until |
|
the first model validation. Set this to `('model', 'type_adapter')` to make `TypeAdapter` respect the `defer_build` |
|
so it postpones validator and serializer construction until the first validation or serialization. |
|
|
|
!!! note |
|
The `experimental_defer_build_mode` parameter is named with an underscore to suggest this is an experimental feature. It may |
|
be removed or changed in the future in a minor release. |
|
""" |
|
|
|
plugin_settings: dict[str, object] | None |
|
"""A `dict` of settings for plugins. Defaults to `None`. |
|
|
|
See [Pydantic Plugins](../concepts/plugins.md) for details. |
|
""" |
|
|
|
schema_generator: type[_GenerateSchema] | None |
|
""" |
|
A custom core schema generator class to use when generating JSON schemas. |
|
Useful if you want to change the way types are validated across an entire model/schema. Defaults to `None`. |
|
|
|
The `GenerateSchema` interface is subject to change, currently only the `string_schema` method is public. |
|
|
|
See [#6737](https://github.com/pydantic/pydantic/pull/6737) for details. |
|
""" |
|
|
|
json_schema_serialization_defaults_required: bool |
|
""" |
|
Whether fields with default values should be marked as required in the serialization schema. Defaults to `False`. |
|
|
|
This ensures that the serialization schema will reflect the fact a field with a default will always be present |
|
when serializing the model, even though it is not required for validation. |
|
|
|
However, there are scenarios where this may be undesirable — in particular, if you want to share the schema |
|
between validation and serialization, and don't mind fields with defaults being marked as not required during |
|
serialization. See [#7209](https://github.com/pydantic/pydantic/issues/7209) for more details. |
|
|
|
```py |
|
from pydantic import BaseModel, ConfigDict |
|
|
|
class Model(BaseModel): |
|
a: str = 'a' |
|
|
|
model_config = ConfigDict(json_schema_serialization_defaults_required=True) |
|
|
|
print(Model.model_json_schema(mode='validation')) |
|
''' |
|
{ |
|
'properties': {'a': {'default': 'a', 'title': 'A', 'type': 'string'}}, |
|
'title': 'Model', |
|
'type': 'object', |
|
} |
|
''' |
|
print(Model.model_json_schema(mode='serialization')) |
|
''' |
|
{ |
|
'properties': {'a': {'default': 'a', 'title': 'A', 'type': 'string'}}, |
|
'required': ['a'], |
|
'title': 'Model', |
|
'type': 'object', |
|
} |
|
''' |
|
``` |
|
""" |
|
|
|
json_schema_mode_override: Literal['validation', 'serialization', None] |
|
""" |
|
If not `None`, the specified mode will be used to generate the JSON schema regardless of what `mode` was passed to |
|
the function call. Defaults to `None`. |
|
|
|
This provides a way to force the JSON schema generation to reflect a specific mode, e.g., to always use the |
|
validation schema. |
|
|
|
It can be useful when using frameworks (such as FastAPI) that may generate different schemas for validation |
|
and serialization that must both be referenced from the same schema; when this happens, we automatically append |
|
`-Input` to the definition reference for the validation schema and `-Output` to the definition reference for the |
|
serialization schema. By specifying a `json_schema_mode_override` though, this prevents the conflict between |
|
the validation and serialization schemas (since both will use the specified schema), and so prevents the suffixes |
|
from being added to the definition references. |
|
|
|
```py |
|
from pydantic import BaseModel, ConfigDict, Json |
|
|
|
class Model(BaseModel): |
|
a: Json[int] # requires a string to validate, but will dump an int |
|
|
|
print(Model.model_json_schema(mode='serialization')) |
|
''' |
|
{ |
|
'properties': {'a': {'title': 'A', 'type': 'integer'}}, |
|
'required': ['a'], |
|
'title': 'Model', |
|
'type': 'object', |
|
} |
|
''' |
|
|
|
class ForceInputModel(Model): |
|
# the following ensures that even with mode='serialization', we |
|
# will get the schema that would be generated for validation. |
|
model_config = ConfigDict(json_schema_mode_override='validation') |
|
|
|
print(ForceInputModel.model_json_schema(mode='serialization')) |
|
''' |
|
{ |
|
'properties': { |
|
'a': { |
|
'contentMediaType': 'application/json', |
|
'contentSchema': {'type': 'integer'}, |
|
'title': 'A', |
|
'type': 'string', |
|
} |
|
}, |
|
'required': ['a'], |
|
'title': 'ForceInputModel', |
|
'type': 'object', |
|
} |
|
''' |
|
``` |
|
""" |
|
|
|
coerce_numbers_to_str: bool |
|
""" |
|
If `True`, enables automatic coercion of any `Number` type to `str` in "lax" (non-strict) mode. Defaults to `False`. |
|
|
|
Pydantic doesn't allow number types (`int`, `float`, `Decimal`) to be coerced as type `str` by default. |
|
|
|
```py |
|
from decimal import Decimal |
|
|
|
from pydantic import BaseModel, ConfigDict, ValidationError |
|
|
|
class Model(BaseModel): |
|
value: str |
|
|
|
try: |
|
print(Model(value=42)) |
|
except ValidationError as e: |
|
print(e) |
|
''' |
|
1 validation error for Model |
|
value |
|
Input should be a valid string [type=string_type, input_value=42, input_type=int] |
|
''' |
|
|
|
class Model(BaseModel): |
|
model_config = ConfigDict(coerce_numbers_to_str=True) |
|
|
|
value: str |
|
|
|
repr(Model(value=42).value) |
|
#> "42" |
|
repr(Model(value=42.13).value) |
|
#> "42.13" |
|
repr(Model(value=Decimal('42.13')).value) |
|
#> "42.13" |
|
``` |
|
""" |
|
|
|
regex_engine: Literal['rust-regex', 'python-re'] |
|
""" |
|
The regex engine to be used for pattern validation. |
|
Defaults to `'rust-regex'`. |
|
|
|
- `rust-regex` uses the [`regex`](https://docs.rs/regex) Rust crate, |
|
which is non-backtracking and therefore more DDoS resistant, but does not support all regex features. |
|
- `python-re` use the [`re`](https://docs.python.org/3/library/re.html) module, |
|
which supports all regex features, but may be slower. |
|
|
|
!!! note |
|
If you use a compiled regex pattern, the python-re engine will be used regardless of this setting. |
|
This is so that flags such as `re.IGNORECASE` are respected. |
|
|
|
```py |
|
from pydantic import BaseModel, ConfigDict, Field, ValidationError |
|
|
|
class Model(BaseModel): |
|
model_config = ConfigDict(regex_engine='python-re') |
|
|
|
value: str = Field(pattern=r'^abc(?=def)') |
|
|
|
print(Model(value='abcdef').value) |
|
#> abcdef |
|
|
|
try: |
|
print(Model(value='abxyzcdef')) |
|
except ValidationError as e: |
|
print(e) |
|
''' |
|
1 validation error for Model |
|
value |
|
String should match pattern '^abc(?=def)' [type=string_pattern_mismatch, input_value='abxyzcdef', input_type=str] |
|
''' |
|
``` |
|
""" |
|
|
|
validation_error_cause: bool |
|
""" |
|
If `True`, Python exceptions that were part of a validation failure will be shown as an exception group as a cause. Can be useful for debugging. Defaults to `False`. |
|
|
|
Note: |
|
Python 3.10 and older don't support exception groups natively. <=3.10, backport must be installed: `pip install exceptiongroup`. |
|
|
|
Note: |
|
The structure of validation errors are likely to change in future Pydantic versions. Pydantic offers no guarantees about their structure. Should be used for visual traceback debugging only. |
|
""" |
|
|
|
use_attribute_docstrings: bool |
|
''' |
|
Whether docstrings of attributes (bare string literals immediately following the attribute declaration) |
|
should be used for field descriptions. Defaults to `False`. |
|
|
|
Available in Pydantic v2.7+. |
|
|
|
```py |
|
from pydantic import BaseModel, ConfigDict, Field |
|
|
|
|
|
class Model(BaseModel): |
|
model_config = ConfigDict(use_attribute_docstrings=True) |
|
|
|
x: str |
|
""" |
|
Example of an attribute docstring |
|
""" |
|
|
|
y: int = Field(description="Description in Field") |
|
""" |
|
Description in Field overrides attribute docstring |
|
""" |
|
|
|
|
|
print(Model.model_fields["x"].description) |
|
# > Example of an attribute docstring |
|
print(Model.model_fields["y"].description) |
|
# > Description in Field |
|
``` |
|
This requires the source code of the class to be available at runtime. |
|
|
|
!!! warning "Usage with `TypedDict`" |
|
Due to current limitations, attribute docstrings detection may not work as expected when using `TypedDict` |
|
(in particular when multiple `TypedDict` classes have the same name in the same source file). The behavior |
|
can be different depending on the Python version used. |
|
''' |
|
|
|
cache_strings: bool | Literal['all', 'keys', 'none'] |
|
""" |
|
Whether to cache strings to avoid constructing new Python objects. Defaults to True. |
|
|
|
Enabling this setting should significantly improve validation performance while increasing memory usage slightly. |
|
|
|
- `True` or `'all'` (the default): cache all strings |
|
- `'keys'`: cache only dictionary keys |
|
- `False` or `'none'`: no caching |
|
|
|
!!! note |
|
`True` or `'all'` is required to cache strings during general validation because |
|
validators don't know if they're in a key or a value. |
|
|
|
!!! tip |
|
If repeated strings are rare, it's recommended to use `'keys'` or `'none'` to reduce memory usage, |
|
as the performance difference is minimal if repeated strings are rare. |
|
""" |
|
|
|
|
|
_TypeT = TypeVar('_TypeT', bound=type) |
|
|
|
|
|
def with_config(config: ConfigDict) -> Callable[[_TypeT], _TypeT]: |
|
"""Usage docs: https://docs.pydantic.dev/2.8/concepts/config/#configuration-with-dataclass-from-the-standard-library-or-typeddict |
|
|
|
A convenience decorator to set a [Pydantic configuration](config.md) on a `TypedDict` or a `dataclass` from the standard library. |
|
|
|
Although the configuration can be set using the `__pydantic_config__` attribute, it does not play well with type checkers, |
|
especially with `TypedDict`. |
|
|
|
!!! example "Usage" |
|
|
|
```py |
|
from typing_extensions import TypedDict |
|
|
|
from pydantic import ConfigDict, TypeAdapter, with_config |
|
|
|
@with_config(ConfigDict(str_to_lower=True)) |
|
class Model(TypedDict): |
|
x: str |
|
|
|
ta = TypeAdapter(Model) |
|
|
|
print(ta.validate_python({'x': 'ABC'})) |
|
#> {'x': 'abc'} |
|
``` |
|
""" |
|
|
|
def inner(class_: _TypeT, /) -> _TypeT: |
|
|
|
|
|
|
|
from ._internal._utils import is_model_class |
|
|
|
if is_model_class(class_): |
|
raise PydanticUserError( |
|
f'Cannot use `with_config` on {class_.__name__} as it is a Pydantic model', |
|
code='with-config-on-model', |
|
) |
|
class_.__pydantic_config__ = config |
|
return class_ |
|
|
|
return inner |
|
|
|
|
|
__getattr__ = getattr_migration(__name__) |
|
|