Header

This class represents a header parameter, inheriting functionality from Param. It is used to define and validate header values, supporting various validation constraints such as length, pattern, and numeric ranges. The class also handles aliases, descriptions, and schema generation for API documentation.

Attributes

Attribute	Type	Description
in_	ParamTypes.header	This attribute stores the parameter type as 'header', indicating that the parameter should be extracted from the request headers.

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Constructor

Signature

def Header(
    default: Any = Undefined,
    default_factory: Callable[[], Any]| None = _Unset,
    annotation: Any | None = null,
    alias: str | None = null,
    alias_priority: int | None = _Unset,
    validation_alias: str | AliasPath | AliasChoices | None = null,
    serialization_alias: str | None = null,
    convert_underscores: bool = true,
    title: str | None = null,
    description: str | None = null,
    gt: float | None = null,
    ge: float | None = null,
    lt: float | None = null,
    le: float | None = null,
    min_length: int | None = null,
    max_length: int | None = null,
    pattern: str | None = null,
    regex: Annotated[str | None, deprecated("Deprecated in FastAPI 0.100.0 and Pydantic v2, use `pattern` instead.")] = null,
    discriminator: str | None = null,
    strict: bool | None = _Unset,
    multiple_of: float | None = _Unset,
    allow_inf_nan: bool | None = _Unset,
    max_digits: int | None = _Unset,
    decimal_places: int | None = _Unset,
    examples: list[Any]| None = null,
    example: Annotated[Any | None, deprecated("Deprecated in OpenAPI 3.1.0 that now uses JSON Schema 2020-12, although still supported. Use examples instead.")] = _Unset,
    openapi_examples: dict[str, [Example](../openapi/models/example.md?sid=fastapi_openapi_models_example)]| None = null,
    deprecated: deprecated | str | bool | None = null,
    include_in_schema: bool = true,
    json_schema_extra: dict[str, Any]| None = null,
    extra: Any = null
) - > null

Parameters

Name	Type	Description
default	Any = Undefined	The default value for the parameter.
default_factory	`Callable[[], Any]	None` = _Unset
annotation	`Any	None` = null
alias	`str	None` = null
alias_priority	`int	None` = _Unset
validation_alias	`str	AliasPath
serialization_alias	`str	None` = null
convert_underscores	bool = true	Whether to convert underscores in the parameter name to hyphens for HTTP headers.
title	`str	None` = null
description	`str	None` = null
gt	`float	None` = null
ge	`float	None` = null
lt	`float	None` = null
le	`float	None` = null
min_length	`int	None` = null
max_length	`int	None` = null
pattern	`str	None` = null
regex	`Annotated[str	None, deprecated("Deprecated in FastAPI 0.100.0 and Pydantic v2, use pattern instead.")]` = null
discriminator	`str	None` = null
strict	`bool	None` = _Unset
multiple_of	`float	None` = _Unset
allow_inf_nan	`bool	None` = _Unset
max_digits	`int	None` = _Unset
decimal_places	`int	None` = _Unset
examples	`list[Any]	None` = null
example	`Annotated[Any	None, deprecated("Deprecated in OpenAPI 3.1.0 that now uses JSON Schema 2020-12, although still supported. Use examples instead.")]` = _Unset
openapi_examples	`dict[str, Example]	None` = null
deprecated	`deprecated	str
include_in_schema	bool = true	Whether to include the parameter in the OpenAPI schema.
json_schema_extra	`dict[str, Any]	None` = null
extra	Any = null	Additional keyword arguments.

---

Signature

def Header(
    default: Any = Undefined,
    default_factory: Callable[[], Any]| None = _Unset,
    annotation: Any | None = null,
    alias: str | None = null,
    alias_priority: int | None = _Unset,
    validation_alias: str | AliasPath | AliasChoices | None = null,
    serialization_alias: str | None = null,
    convert_underscores: bool = true,
    title: str | None = null,
    description: str | None = null,
    gt: float | None = null,
    ge: float | None = null,
    lt: float | None = null,
    le: float | None = null,
    min_length: int | None = null,
    max_length: int | None = null,
    pattern: str | None = null,
    regex: Annotated[str | None, deprecated("Deprecated in FastAPI 0.100.0 and Pydantic v2, use `pattern` instead.")] = null,
    discriminator: str | None = null,
    strict: bool | None = _Unset,
    multiple_of: float | None = _Unset,
    allow_inf_nan: bool | None = _Unset,
    max_digits: int | None = _Unset,
    decimal_places: int | None = _Unset,
    examples: list[Any]| None = null,
    example: Annotated[Any | None, deprecated("Deprecated in OpenAPI 3.1.0 that now uses JSON Schema 2020-12, although still supported. Use examples instead.")] = _Unset,
    openapi_examples: dict[str, [Example](../openapi/models/example.md?sid=fastapi_openapi_models_example)]| None = null,
    deprecated: deprecated | str | bool | None = null,
    include_in_schema: bool = true,
    json_schema_extra: dict[str, Any]| None = null,
    extra: Any = null
) - > null

Parameters

Name	Type	Description
default	Any = Undefined	The default value for the header if it is not provided. Use Undefined if there is no default value.
default_factory	`Callable[[], Any]	None` = _Unset
annotation	`Any	None` = null
alias	`str	None` = null
alias_priority	`int	None` = _Unset
validation_alias	`str	AliasPath
serialization_alias	`str	None` = null
convert_underscores	bool = true	A boolean indicating whether underscores in the header name should be converted to hyphens for HTTP header compatibility.
title	`str	None` = null
description	`str	None` = null
gt	`float	None` = null
ge	`float	None` = null
lt	`float	None` = null
le	`float	None` = null
min_length	`int	None` = null
max_length	`int	None` = null
pattern	`str	None` = null
regex	`Annotated[str	None, deprecated("Deprecated in FastAPI 0.100.0 and Pydantic v2, use pattern instead.")]` = null
discriminator	`str	None` = null
strict	`bool	None` = _Unset
multiple_of	`float	None` = _Unset
allow_inf_nan	`bool	None` = _Unset
max_digits	`int	None` = _Unset
decimal_places	`int	None` = _Unset
examples	`list[Any]	None` = null
example	`Annotated[Any	None, deprecated("Deprecated in OpenAPI 3.1.0 that now uses JSON Schema 2020-12, although still supported. Use examples instead.")]` = _Unset
openapi_examples	`dict[str, Example]	None` = null
deprecated	`deprecated	str
include_in_schema	bool = true	A boolean indicating whether the header parameter should be included in the generated OpenAPI schema.
json_schema_extra	`dict[str, Any]	None` = null
extra	Any = null	Additional keyword arguments that can be passed to the underlying Pydantic Field.

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