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from __future__ import annotations
from types import MappingProxyType
from typing import Any
from itemadapter._imports import (
PydanticUndefined,
PydanticV1Undefined,
attr,
pydantic,
pydantic_v1,
)
__all__ = ["get_field_meta_from_class", "is_item"]
def _is_attrs_class(obj: Any) -> bool:
if attr is None:
return False
return attr.has(obj)
def _is_pydantic_model(obj: Any) -> bool:
if pydantic is None:
return False
return issubclass(obj, pydantic.BaseModel)
def _is_pydantic_v1_model(obj: Any) -> bool:
if pydantic_v1 is None:
return False
return issubclass(obj, pydantic_v1.BaseModel)
def _get_pydantic_model_metadata(item_model: Any, field_name: str) -> MappingProxyType:
metadata = {}
field = item_model.model_fields[field_name]
for attribute in [
"alias_priority",
"alias",
"allow_inf_nan",
"annotation",
"coerce_numbers_to_str",
"decimal_places",
"default_factory",
"deprecated",
"description",
"discriminator",
"examples",
"exclude",
"fail_fast",
"field_title_generator",
"frozen",
"ge",
"gt",
"init_var",
"init",
"json_schema_extra",
"kw_only",
"le",
"lt",
"max_digits",
"max_length",
"min_length",
"multiple_of",
"pattern",
"repr",
"serialization_alias",
"strict",
"title",
"union_mode",
"validate_default",
"validation_alias",
]:
if hasattr(field, attribute) and (value := getattr(field, attribute)) is not None:
metadata[attribute] = value
for attribute, default_value in [
("default", PydanticUndefined),
("metadata", []),
]:
if hasattr(field, attribute) and (value := getattr(field, attribute)) != default_value:
metadata[attribute] = value
return MappingProxyType(metadata)
def _get_pydantic_v1_model_metadata(item_model: Any, field_name: str) -> MappingProxyType:
metadata = {}
field = item_model.__fields__[field_name]
field_info = field.field_info
for attribute in [
"alias",
"const",
"description",
"ge",
"gt",
"le",
"lt",
"max_items",
"max_length",
"min_items",
"min_length",
"multiple_of",
"regex",
"title",
]:
value = getattr(field_info, attribute)
if value is not None:
metadata[attribute] = value
if (value := field_info.default) not in (PydanticV1Undefined, Ellipsis):
metadata["default"] = value
if value := field.default_factory is not None:
metadata["default_factory"] = value
if not field_info.allow_mutation:
metadata["allow_mutation"] = field_info.allow_mutation
metadata.update(field_info.extra)
return MappingProxyType(metadata)
def is_item(obj: Any) -> bool:
"""Return True if the given object belongs to one of the supported types, False otherwise.
Alias for ItemAdapter.is_item
"""
from itemadapter.adapter import ItemAdapter
return ItemAdapter.is_item(obj)
def get_field_meta_from_class(item_class: type, field_name: str) -> MappingProxyType:
"""Return a read-only mapping with metadata for the given field name, within the given
item class. If there is no metadata for the field, or the item class does not support
field metadata, an empty object is returned.
Field metadata is taken from different sources, depending on the item type:
* scrapy.item.Item: corresponding scrapy.item.Field object
* dataclass items: "metadata" attribute for the corresponding field
* attrs items: "metadata" attribute for the corresponding field
* pydantic models: corresponding pydantic.field.FieldInfo/ModelField object
The returned value is an instance of types.MappingProxyType, i.e. a dynamic read-only view
of the original mapping, which gets automatically updated if the original mapping changes.
"""
from itemadapter.adapter import ItemAdapter
return ItemAdapter.get_field_meta_from_class(item_class, field_name)
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