Source code for dataclass_wizard.bases
from __future__ import annotations
from abc import ABCMeta, abstractmethod
from datetime import tzinfo
from typing import (Callable, Type, Dict, Optional, ClassVar, Union,
TypeVar, Mapping, Sequence, TYPE_CHECKING, Any, Literal)
from .constants import TAG
from .decorators import cached_class_property
from .enums import DateTimeTo, LetterCase, LetterCasePriority
from .models import Condition
if TYPE_CHECKING:
from .v1.enums import KeyAction, KeyCase, DateTimeTo as V1DateTimeTo, EnvKeyStrategy, EnvPrecedence
from .v1._path_util import EnvFilePaths, SecretsDirs
from .bases_meta import ALLOWED_MODES, V1HookFn, V1PreDecoder
from .type_def import FrozenKeys
V1TypeToHook = Mapping[type, Union[tuple[ALLOWED_MODES, V1HookFn], V1HookFn, None]]
# Create a generic variable that can be 'AbstractMeta', or any subclass.
# Full word as `M` is already defined in another module
META_ = TypeVar('META_', bound='AbstractMeta')
# Use `type` here explicitly, because we will never have an `META_` object.
META = type[META_]
# Create a generic variable that can be 'AbstractMeta', or any subclass.
# Full word as `M` is already defined in another module
ENV_META_ = TypeVar('ENV_META_', bound='AbstractEnvMeta')
# Use `type` here explicitly, because we will never have an `META_` object.
ENV_META = type[ENV_META_]
[docs]
class ABCOrAndMeta(ABCMeta):
"""
Metaclass to add class-level :meth:`__or__` and :meth:`__and__` methods
to a base class of type :type:`M`.
Ref:
- https://stackoverflow.com/q/15008807/10237506
- https://stackoverflow.com/a/57351066/10237506
"""
def __or__(cls: META, other: META) -> META:
"""
Merge two Meta configs. Priority will be given to the source config
present in `cls`, e.g. the first operand in the '|' expression.
Use case: Merge the Meta configs for two separate dataclasses into a
single, unified Meta config.
"""
src = cls
src_dict = src.__dict__
other_dict = other.__dict__
base_dict = {'__slots__': ()}
# Set meta attributes here.
if src is AbstractMeta or src is AbstractEnvMeta:
# Here we can't use `src` because the `bind_to` method isn't
# defined on the abstract class. Use `other` instead, which
# *will* be a concrete subclass of `AbstractMeta`.
src = other
# noinspection PyTypeChecker
for k in src.fields_to_merge:
if k in other_dict:
base_dict[k] = other_dict[k]
else:
# noinspection PyTypeChecker
for k in src.fields_to_merge:
if k in src_dict:
base_dict[k] = src_dict[k]
elif k in other_dict:
base_dict[k] = other_dict[k]
# This mapping won't be updated. Use the src by default.
for k in src.__special_attrs__:
if k in src_dict:
base_dict[k] = src_dict[k]
new_cls_name = src.__name__
# Check if the type of the class we want to create is
# `JSONWizard.Meta` or a subclass. If so, we want to avoid the
# mandatory `__init_subclass__` call that gets invoked when creating
# a new class, so use the superclass type instead.
if src.__is_inner_meta__:
# In a reversed MRO, the inheritance tree looks like this:
# |___ object -> AbstractMeta -> BaseJSONWizardMeta -> ...
# So here, we want to choose the third-to-last class in the list.
# noinspection PyUnresolvedReferences
src = src.__mro__[-3]
# noinspection PyTypeChecker
return type(new_cls_name, (src, ), base_dict)
def __and__(cls: META, other: META) -> META:
"""
Merge the `other` Meta config into the first one, i.e. `cls`. This
operation does not create a new class, but instead it modifies the
source config `cls` in-place; the source will be the first operand in
the '&' expression.
Use case: Merge a separate Meta config (for a single dataclass) with
the first config.
"""
other_dict = other.__dict__
# Set meta attributes here.
# noinspection PyTypeChecker
for k in cls.all_fields:
if k in other_dict:
setattr(cls, k, other_dict[k])
return cls
[docs]
class AbstractMeta(metaclass=ABCOrAndMeta):
"""
Base class definition for the `JSONWizard.Meta` inner class.
"""
__slots__ = ()
# A list of class attributes that are exclusive to the Meta config.
# When merging two Meta configs for a class, these are the only
# attributes which will *not* be merged.
__special_attrs__ = frozenset({
'recursive',
'json_key_to_field',
'v1_field_to_alias',
'v1_field_to_alias_dump',
'v1_field_to_alias_load',
'tag',
})
# Class attribute which enables us to detect a `JSONWizard.Meta` subclass.
__is_inner_meta__ = False
# Enable Debug mode for more verbose log output.
#
# This setting can be a `bool`, `int`, or `str`:
# - `True` enables debug mode with default verbosity.
# - A `str` or `int` specifies the minimum log level (e.g., 'DEBUG', 10).
#
# Debug mode provides additional helpful log messages, including:
# - Logging unknown JSON keys encountered during `from_dict` or `from_json`.
# - Detailed error messages for invalid types during unmarshalling.
#
# Note: Enabling Debug mode may have a minor performance impact.
#
# @deprecated and will be removed in V1 - Use `v1_debug` instead.
debug_enabled: ClassVar['bool | int | str'] = False
# When enabled, a specified Meta config for the main dataclass (i.e. the
# class on which `from_dict` and `to_dict` is called) will cascade down
# and be merged with the Meta config for each *nested* dataclass; note
# that during a merge, priority is given to the Meta config specified on
# each class.
#
# The default behavior is True, so the Meta config (if provided) will
# apply in a recursive manner.
recursive: ClassVar[bool] = True
# True to support cyclic or self-referential dataclasses. For example,
# the type of a dataclass field in class `A` refers to `A` itself.
#
# See https://github.com/rnag/dataclass-wizard/issues/62 for more details.
recursive_classes: ClassVar[bool] = False
# True to raise an class:`UnknownJSONKey` when an unmapped JSON key is
# encountered when `from_dict` or `from_json` is called; an unknown key is
# one that does not have a known mapping to a dataclass field.
#
# The default is to only log a "warning" for such cases, which is visible
# when `v1_debug` is true and logging is properly configured.
raise_on_unknown_json_key: ClassVar[bool] = False
# A customized mapping of JSON keys to dataclass fields, that is used
# whenever `from_dict` or `from_json` is called.
#
# Note: this is in addition to the implicit field transformations, like
# "myStr" -> "my_str"
#
# If the reverse mapping is also desired (i.e. dataclass field to JSON
# key), then specify the "__all__" key as a truthy value. If multiple JSON
# keys are specified for a dataclass field, only the first one provided is
# used in this case.
json_key_to_field: ClassVar[Dict[str, str]] = None
# How should :class:`time` and :class:`datetime` objects be serialized
# when converted to a Python dictionary object or a JSON string.
marshal_date_time_as: ClassVar[Union[DateTimeTo, str]] = None
# How JSON keys should be transformed to dataclass fields.
#
# Note that this only applies to keys which are to be set on dataclass
# fields; other fields such as the ones for `TypedDict` or `NamedTuple`
# sub-classes won't be similarly transformed.
key_transform_with_load: ClassVar[Union[LetterCase, str]] = None
# How dataclass fields should be transformed to JSON keys.
#
# Note that this only applies to dataclass fields; other fields such as
# the ones for `TypedDict` or `NamedTuple` sub-classes won't be similarly
# transformed.
key_transform_with_dump: ClassVar[Union[LetterCase, str]] = None
# The field name that identifies the tag for a class.
#
# When set to a value, an :attr:`TAG` field will be populated in the
# dictionary object in the dump (serialization) process. When loading
# (or de-serializing) a dictionary object, the :attr:`TAG` field will be
# used to load the corresponding dataclass, assuming the dataclass field
# is properly annotated as a Union type, ex.:
# my_data: Union[Data1, Data2, Data3]
tag: ClassVar[str] = None
# The dictionary key that identifies the tag field for a class. This is
# only set when the `tag` field or the `auto_assign_tags` flag is enabled
# in the `Meta` config for a dataclass.
#
# Defaults to '__tag__' if not specified.
tag_key: ClassVar[str] = TAG
# Auto-assign the class name as a dictionary "tag" key, for any dataclass
# fields which are in a `Union` declaration, ex.:
# my_data: Union[Data1, Data2, Data3]
auto_assign_tags: ClassVar[bool] = False
# Determines whether we should we skip / omit fields with default values
# (based on the `default` or `default_factory` argument specified for
# the :func:`dataclasses.field`) in the serialization process.
skip_defaults: ClassVar[bool] = False
# Determines the :class:`Condition` to skip / omit dataclass
# fields in the serialization process.
skip_if: ClassVar[Condition] = None
# Determines the condition to skip / omit fields with default values
# (based on the `default` or `default_factory` argument specified for
# the :func:`dataclasses.field`) in the serialization process.
skip_defaults_if: ClassVar[Condition] = None
# Enable opt-in to the "experimental" major release `v1` feature.
# This feature offers optimized performance for de/serialization.
# Defaults to False.
v1: ClassVar[bool] = False
# Enable Debug mode for more verbose log output.
#
# This setting can be a `bool`, `int`, or `str`:
# - `True` enables debug mode with default verbosity.
# - A `str` or `int` specifies the minimum log level (e.g., 'DEBUG', 10).
#
# Debug mode provides additional helpful log messages, including:
# - Logging unknown JSON keys encountered during `from_dict` or `from_json`.
# - Detailed error messages for invalid types during unmarshalling.
#
# Note: Enabling Debug mode may have a minor performance impact.
v1_debug: ClassVar['bool | int | str'] = False
# Custom load hooks for extending type support in the v1 engine.
#
# Mapping: {Type -> hook}
#
# A hook must accept either:
# - one positional argument (runtime hook): value -> object
# - two positional arguments (v1 hook): (TypeInfo, Extras) -> str | TypeInfo
#
# The hook is invoked when loading a value annotated with the given type.
v1_type_to_load_hook: ClassVar[V1TypeToHook] = None
# Custom dump hooks for extending type support in the v1 engine.
#
# Mapping: {Type -> hook}
#
# A hook must accept either:
# - one positional argument (runtime hook): object -> JSON-serializable value
# - two positional arguments (v1 hook): (TypeInfo, Extras) -> str | TypeInfo
#
# The hook is invoked when dumping a value whose runtime type matches
# the given type.
v1_type_to_dump_hook: ClassVar[V1TypeToHook] = None
# ``v1_pre_decoder``: Optional hook called before ``v1`` type loading.
# Receives the container type plus (cls, TypeInfo, Extras) and may return a
# transformed ``TypeInfo`` (e.g., wrapped in a function which decodes
# JSON/delimited strings into list/dict for env loading). Returning the
# input value leaves behavior unchanged.
#
# Pre-decoder signature:
# (cls, container_tp, tp, extras) -> new_tp
v1_pre_decoder: ClassVar[V1PreDecoder] = None
# Specifies the letter case to use for JSON keys when both loading and dumping.
#
# This is a convenience setting that applies the same key casing rule to
# both deserialization (load) and serialization (dump).
#
# If set, it is used as the default for both `v1_load_case` and
# `v1_dump_case`, unless either is explicitly specified.
#
# The setting is case-insensitive and supports shorthand assignment,
# such as using the string 'C' instead of 'CAMEL'.
v1_case: ClassVar[Union[KeyCase, str, None]] = None
# Specifies the letter case used to match JSON keys when mapping them
# to dataclass fields during deserialization.
#
# This setting determines how dataclass field names are transformed
# when looking up corresponding keys in the input JSON object. It does
# not affect keys in `TypedDict` or `NamedTuple` subclasses.
#
# By default, JSON keys are assumed to be in `snake_case`, and fields
# are matched directly without transformation.
#
# The setting is case-insensitive and supports shorthand assignment,
# such as using the string 'C' instead of 'CAMEL'.
#
# If set to `A` or `AUTO`, all supported key casing transforms are
# attempted at runtime, and the resolved transform is cached for
# subsequent lookups.
#
# If unset, this value defaults to `v1_case` when provided.
v1_load_case: ClassVar[Union[KeyCase, str, None]] = None
# Specifies the letter case used for JSON keys during serialization.
#
# This setting determines how dataclass field names are transformed
# when generating keys in the output JSON object.
#
# By default, field names are emitted in `snake_case`.
#
# The setting is case-insensitive and supports shorthand assignment,
# such as using the string 'P' instead of 'PASCAL'.
#
# If unset, this value defaults to `v1_case` when provided.
v1_dump_case: ClassVar[Union[KeyCase, str, None]] = None
# A custom mapping of dataclass fields to their JSON aliases (keys).
#
# Values may be a single alias string or a sequence of alias strings.
#
# - During deserialization (load), any listed alias for a field is accepted.
# - During serialization (dump), the first alias is used by default.
#
# This mapping overrides default key casing and implicit field-to-key
# transformations (e.g., "my_field" → "myField") for the affected fields.
#
# This setting applies to both load and dump unless explicitly overridden
# by `v1_field_to_alias_load` or `v1_field_to_alias_dump`.
v1_field_to_alias: ClassVar[
Mapping[str, Union[str, Sequence[str]]]
] = None
# A custom mapping of dataclass fields to their JSON aliases (keys) used
# during deserialization only.
#
# Values may be a single alias string or a sequence of alias strings.
# Any listed alias is accepted when mapping input JSON keys to
# dataclass fields.
#
# When set, this mapping overrides `v1_field_to_alias` for load behavior
# only.
v1_field_to_alias_load: ClassVar[
Mapping[str, Union[str, Sequence[str]]]
] = None
# A custom mapping of dataclass fields to their JSON aliases (keys) used
# during serialization only.
#
# Values may be a single alias string or a sequence of alias strings.
# When a sequence is provided, the first alias is used as the output key.
#
# When set, this mapping overrides `v1_field_to_alias` for dump behavior
# only.
v1_field_to_alias_dump: ClassVar[
Mapping[str, Union[str, Sequence[str]]]
] = None
# Defines the action to take when an unknown JSON key is encountered during
# `from_dict` or `from_json` calls. An unknown key is one that does not map
# to any dataclass field.
#
# Valid options are:
# - `"ignore"` (default): Silently ignore unknown keys.
# - `"warn"`: Log a warning for each unknown key. Requires `v1_debug`
# to be `True` and properly configured logging.
# - `"raise"`: Raise an `UnknownKeyError` for the first unknown key encountered.
v1_on_unknown_key: ClassVar[KeyAction] = None
# Unsafe: Enables parsing of dataclasses in unions without requiring
# the presence of a `tag_key`, i.e., a dictionary key identifying the
# tag field in the input. Defaults to False.
v1_unsafe_parse_dataclass_in_union: ClassVar[bool] = False
# Specifies how :class:`datetime` (and :class:`time`, where applicable)
# objects are serialized during output.
#
# This setting controls how temporal values are emitted when converting
# a dataclass to a Python dictionary (`to_dict`) or a JSON string
# (`to_json`). It applies to serialization only and does not affect
# deserialization.
#
# By default, values are serialized using ISO 8601 string format.
#
# Supported values are defined by :class:`DateTimeTo`.
v1_dump_date_time_as: ClassVar[Union[V1DateTimeTo, str]] = None
# Specifies the timezone to assume for naive :class:`datetime` values
# during serialization.
#
# By default, naive datetimes are rejected to avoid ambiguous or
# environment-dependent behavior.
#
# When set, naive datetimes are interpreted as being in the specified
# timezone before conversion to a UTC epoch timestamp.
#
# Common usage:
# v1_assume_naive_datetime_tz = timezone.utc
#
# This setting applies to serialization only and does not affect
# deserialization.
v1_assume_naive_datetime_tz: ClassVar[tzinfo | None] = None
# Controls how `typing.NamedTuple` and `collections.namedtuple`
# fields are loaded and serialized.
#
# - False (DEFAULT): load from list/tuple and serialize
# as a positional list.
# - True: load from mapping and serialize as a dict
# keyed by field name.
#
# In strict mode, inputs that do not match the selected mode
# raise TypeError.
#
# Note:
# This option enforces strict shape matching for performance reasons.
v1_namedtuple_as_dict: ClassVar[bool] = None
# If True (default: False), ``None`` is coerced to an empty string (``""``)
# when loading ``str`` fields.
#
# When False, ``None`` is coerced using ``str(value)``, so ``None`` becomes
# the literal string ``'None'`` for ``str`` fields.
#
# For ``Optional[str]`` fields, ``None`` is preserved by default.
v1_coerce_none_to_empty_str: ClassVar[bool] = None
# Controls how leaf (non-recursive) types are detected during serialization.
#
# - "exact" (DEFAULT): only exact built-in leaf types are treated as leaf values.
# - "issubclass": subclasses of leaf types are also treated as leaf values.
#
# Leaf types are returned without recursive traversal. Bytes are still
# handled separately according to their serialization rules.
#
# Note:
# The default "exact" mode avoids treating third-party scalar-like
# objects (e.g. NumPy scalars) as built-in leaf types.
v1_leaf_handling: ClassVar[Literal['exact', 'issubclass']] = None
# noinspection PyMethodParameters
@cached_class_property
def all_fields(cls) -> FrozenKeys:
"""Return a list of all class attributes"""
return frozenset(AbstractMeta.__annotations__)
# noinspection PyMethodParameters
@cached_class_property
def fields_to_merge(cls) -> FrozenKeys:
"""Return a list of class attributes, minus `__special_attrs__`"""
return cls.all_fields - cls.__special_attrs__
[docs]
@classmethod
@abstractmethod
def bind_to(cls, dataclass: Type, create=True, is_default=True):
"""
Initialize hook which applies the Meta config to `dataclass`, which is
typically a subclass of :class:`JSONWizard`.
:param dataclass: A class which has been decorated by the `@dataclass`
decorator; typically this is a sub-class of :class:`JSONWizard`.
:param create: When true, a separate loader/dumper will be created
for the class. If disabled, this will access the root loader/dumper,
so modifying this should affect global settings across all
dataclasses that use the JSON load/dump process.
:param is_default: When enabled, the Meta will be cached as the
default Meta config for the dataclass. Defaults to true.
"""
[docs]
class AbstractEnvMeta(metaclass=ABCOrAndMeta):
"""
Base class definition for the `EnvWizard.Meta` inner class.
"""
__slots__ = ()
# A list of class attributes that are exclusive to the Meta config.
# When merging two Meta configs for a class, these are the only
# attributes which will *not* be merged.
__special_attrs__ = frozenset({
'recursive',
'debug_enabled',
'env_var_to_field',
'v1_field_to_env_load',
'v1_field_to_alias_dump',
'tag',
})
# Class attribute which enables us to detect a `EnvWizard.Meta` subclass.
__is_inner_meta__ = False
# True to enable Debug mode for additional (more verbose) log output.
#
# For example, a message is logged with the environment variable that is
# mapped to each attribute.
#
# This also results in more helpful messages during error handling, which
# can be useful when debugging the cause when values are an invalid type
# (i.e. they don't match the annotation for the field) when unmarshalling
# a environ variable values to attributes in an EnvWizard subclass.
#
# Note there is a minor performance impact when DEBUG mode is enabled.
debug_enabled: ClassVar[bool] = False
# When enabled, a specified Meta config for the main dataclass (i.e. the
# class on which `from_dict` and `to_dict` is called) will cascade down
# and be merged with the Meta config for each *nested* dataclass; note
# that during a merge, priority is given to the Meta config specified on
# each class.
#
# The default behavior is True, so the Meta config (if provided) will
# apply in a recursive manner.
recursive: ClassVar[bool] = True
# `True` to load environment variables from an `.env` file, or a
# list/tuple of dotenv files.
#
# This can also be set to a path to a custom dotenv file, for example:
# `path/to/.env.prod`
#
# Simply passing in a filename such as `.env.prod` will search the current
# directory, as well as any parent folders (working backwards to the root
# directory), until it locates the given file.
#
# If multiple files are passed in, later files in the list/tuple will take
# priority over earlier files.
#
# For example, in below the '.env.last' file takes priority over '.env':
# env_file = '.env', '.env.last'
env_file: ClassVar[EnvFilePaths] = None
# Prefix for all environment variables. Defaults to `None`.
env_prefix: ClassVar[str] = None
# secrets_dir: The secret files directory or a sequence of directories. Defaults to `None`.
secrets_dir: ClassVar[SecretsDirs] = None
# -- BEGIN Deprecated Fields --
# The nested env values delimiter. Defaults to `None`.
# env_nested_delimiter: ClassVar[str] = None
# A customized mapping of field in the `EnvWizard` subclass to its
# corresponding environment variable to search for.
#
# Note: this is in addition to the implicit field transformations, like
# "myStr" -> "my_str"
field_to_env_var: ClassVar[Dict[str, str]] = None
# The letter casing priority to use when looking up Env Var Names.
#
# The default is `SCREAMING_SNAKE_CASE`.
key_lookup_with_load: ClassVar[Union[LetterCasePriority, str]] = LetterCasePriority.SCREAMING_SNAKE
# How `EnvWizard` fields (variables) should be transformed to JSON keys.
#
# The default is 'snake_case'.
key_transform_with_dump: ClassVar[Union[LetterCase, str]] = LetterCase.SNAKE
# -- END Deprecated Fields --
# Determines whether we should we skip / omit fields with default values
# in the serialization process.
skip_defaults: ClassVar[bool] = False
# Determines the :class:`Condition` to skip / omit dataclass
# fields in the serialization process.
skip_if: ClassVar[Condition] = None
# Determines the condition to skip / omit fields with default values
# (based on the `default` or `default_factory` argument specified for
# the :func:`dataclasses.field`) in the serialization process.
skip_defaults_if: ClassVar[Condition] = None
# The field name that identifies the tag for a class.
#
# When set to a value, an :attr:`TAG` field will be populated in the
# dictionary object in the dump (serialization) process. When loading
# (or de-serializing) a dictionary object, the :attr:`TAG` field will be
# used to load the corresponding dataclass, assuming the dataclass field
# is properly annotated as a Union type, ex.:
# my_data: Union[Data1, Data2, Data3]
tag: ClassVar[str] = None
# The dictionary key that identifies the tag field for a class. This is
# only set when the `tag` field or the `auto_assign_tags` flag is enabled
# in the `Meta` config for a dataclass.
#
# Defaults to '__tag__' if not specified.
tag_key: ClassVar[str] = TAG
# Auto-assign the class name as a dictionary "tag" key, for any dataclass
# fields which are in a `Union` declaration, ex.:
# my_data: Union[Data1, Data2, Data3]
auto_assign_tags: ClassVar[bool] = False
# Enable opt-in to the "experimental" major release `v1` feature.
# This feature offers optimized performance for de/serialization.
# Defaults to False.
v1: ClassVar[bool] = False
# Enable Debug mode for more verbose log output.
#
# This setting can be a `bool`, `int`, or `str`:
# - `True` enables debug mode with default verbosity.
# - A `str` or `int` specifies the minimum log level (e.g., 'DEBUG', 10).
#
# Debug mode provides additional helpful log messages, including:
# - Logging unknown JSON keys encountered during `from_dict` or `from_json`.
# - Detailed error messages for invalid types during unmarshalling.
#
# Note: Enabling Debug mode may have a minor performance impact.
v1_debug: ClassVar['bool | int | str'] = False
# Custom load hooks for extending type support in the v1 engine.
#
# Mapping: {Type -> hook}
#
# A hook must accept either:
# - one positional argument (runtime hook): value -> object
# - two positional arguments (v1 hook): (TypeInfo, Extras) -> str | TypeInfo
#
# The hook is invoked when loading a value annotated with the given type.
v1_type_to_load_hook: ClassVar[V1TypeToHook] = None
# Custom dump hooks for extending type support in the v1 engine.
#
# Mapping: {Type -> hook}
#
# A hook must accept either:
# - one positional argument (runtime hook): object -> JSON-serializable value
# - two positional arguments (v1 hook): (TypeInfo, Extras) -> str | TypeInfo
#
# The hook is invoked when dumping a value whose runtime type matches
# the given type.
v1_type_to_dump_hook: ClassVar[V1TypeToHook] = None
# ``v1_pre_decoder``: Optional hook called before ``v1`` type loading.
# Receives the container type plus (cls, TypeInfo, Extras) and may return a
# transformed ``TypeInfo`` (e.g., wrapped in a function which decodes
# JSON/delimited strings into list/dict for env loading). Returning the
# input value leaves behavior unchanged.
#
# Pre-decoder signature:
# (cls, container_tp, tp, extras) -> new_tp
v1_pre_decoder: ClassVar[V1PreDecoder] = None
# The key lookup strategy to use for Env Var Names.
#
# The default strategy is `SCREAMING_SNAKE_CASE` > `snake_case`.
v1_load_case: ClassVar[Union[EnvKeyStrategy, str]] = None
# How `EnvWizard` fields (variables) should be transformed to JSON keys.
#
# The default is 'snake_case'.
v1_dump_case: ClassVar[Union[LetterCase, str]] = None
# Environment Precedence (order) to search for values
# Defaults to EnvPrecedence.SECRETS_ENV_DOTENV
v1_env_precedence: EnvPrecedence = None
# A custom mapping of dataclass fields to their env vars (keys) used
# during deserialization only.
#
# Values may be a single alias string or a sequence of alias strings.
# Any listed alias is accepted when mapping input env vars to
# dataclass fields.
v1_field_to_env_load: ClassVar[
Mapping[str, Union[str, Sequence[str]]]
] = None
# A custom mapping of dataclass fields to their JSON aliases (keys) used
# during serialization only.
#
# Values may be a single alias string or a sequence of alias strings.
# When a sequence is provided, the first alias is used as the output key.
#
# When set, this mapping overrides `v1_field_to_alias` for dump behavior
# only.
v1_field_to_alias_dump: ClassVar[
Mapping[str, Union[str, Sequence[str]]]
] = None
# Defines the action to take when an unknown JSON key is encountered during
# `from_dict` or `from_json` calls. An unknown key is one that does not map
# to any dataclass field.
#
# Valid options are:
# - `"ignore"` (default): Silently ignore unknown keys.
# - `"warn"`: Log a warning for each unknown key. Requires `v1_debug`
# to be `True` and properly configured logging.
# - `"raise"`: Raise an `UnknownKeyError` for the first unknown key encountered.
# v1_on_unknown_key: ClassVar[KeyAction] = None
# Unsafe: Enables parsing of dataclasses in unions without requiring
# the presence of a `tag_key`, i.e., a dictionary key identifying the
# tag field in the input. Defaults to False.
v1_unsafe_parse_dataclass_in_union: ClassVar[bool] = False
# Specifies how :class:`datetime` (and :class:`time`, where applicable)
# objects are serialized during output.
#
# This setting controls how temporal values are emitted when converting
# a dataclass to a Python dictionary (`to_dict`) or a JSON string
# (`to_json`). It applies to serialization only and does not affect
# deserialization.
#
# By default, values are serialized using ISO 8601 string format.
#
# Supported values are defined by :class:`DateTimeTo`.
v1_dump_date_time_as: ClassVar[Union[V1DateTimeTo, str]] = None
# Specifies the timezone to assume for naive :class:`datetime` values
# during serialization.
#
# By default, naive datetimes are rejected to avoid ambiguous or
# environment-dependent behavior.
#
# When set, naive datetimes are interpreted as being in the specified
# timezone before conversion to a UTC epoch timestamp.
#
# Common usage:
# v1_assume_naive_datetime_tz = timezone.utc
#
# This setting applies to serialization only and does not affect
# deserialization.
v1_assume_naive_datetime_tz: ClassVar[tzinfo | None] = None
# Controls how `typing.NamedTuple` and `collections.namedtuple`
# fields are loaded and serialized.
#
# - False (DEFAULT): load from list/tuple and serialize
# as a positional list.
# - True: load from mapping and serialize as a dict
# keyed by field name.
#
# In strict mode, inputs that do not match the selected mode
# raise TypeError.
#
# Note:
# This option enforces strict shape matching for performance reasons.
v1_namedtuple_as_dict: ClassVar[bool] = None
# If True (default: False), ``None`` is coerced to an empty string (``""``)
# when loading ``str`` fields.
#
# When False, ``None`` is coerced using ``str(value)``, so ``None`` becomes
# the literal string ``'None'`` for ``str`` fields.
#
# For ``Optional[str]`` fields, ``None`` is preserved by default.
v1_coerce_none_to_empty_str: ClassVar[bool] = None
# Controls how leaf (non-recursive) types are detected during serialization.
#
# - "exact" (DEFAULT): only exact built-in leaf types are treated as leaf values.
# - "issubclass": subclasses of leaf types are also treated as leaf values.
#
# Leaf types are returned without recursive traversal. Bytes are still
# handled separately according to their serialization rules.
#
# Note:
# The default "exact" mode avoids treating third-party scalar-like
# objects (e.g. NumPy scalars) as built-in leaf types.
v1_leaf_handling: ClassVar[Literal['exact', 'issubclass']] = None
# noinspection PyMethodParameters
@cached_class_property
def all_fields(cls) -> FrozenKeys:
"""Return a list of all class attributes"""
return frozenset(AbstractEnvMeta.__annotations__)
# noinspection PyMethodParameters
@cached_class_property
def fields_to_merge(cls) -> FrozenKeys:
"""Return a list of class attributes, minus `__special_attrs__`"""
return cls.all_fields - cls.__special_attrs__
[docs]
@classmethod
@abstractmethod
def bind_to(cls, env_class: Type, create=True, is_default=True):
"""
Initialize hook which applies the Meta config to `env_class`, which is
typically a subclass of :class:`EnvWizard`.
:param env_class: A sub-class of :class:`EnvWizard`.
:param create: When true, a separate loader/dumper will be created
for the class. If disabled, this will access the root loader/dumper,
so modifying this should affect global settings across all
dataclasses that use the JSON load/dump process.
:param is_default: When enabled, the Meta will be cached as the
default Meta config for the dataclass. Defaults to true.
"""
[docs]
class BaseLoadHook:
"""
Container class for type hooks.
"""
__slots__ = ()
__LOAD_HOOKS__: ClassVar[Dict[Type, Callable]] = None
def __init_subclass__(cls):
super().__init_subclass__()
# (Re)assign the dict object so we have a fresh copy per class
cls.__LOAD_HOOKS__ = {}
[docs]
@classmethod
def register_load_hook(cls, typ: Type, func: Callable):
"""Registers the hook for a type, on the default loader by default."""
cls.__LOAD_HOOKS__[typ] = func
[docs]
@classmethod
def get_load_hook(cls, typ: Type) -> Optional[Callable]:
"""Retrieves the hook for a type, if one exists."""
return cls.__LOAD_HOOKS__.get(typ)
[docs]
class BaseDumpHook:
"""
Container class for type hooks.
"""
__slots__ = ()
__DUMP_HOOKS__: ClassVar[Dict[Type, Callable]] = None
def __init_subclass__(cls):
super().__init_subclass__()
# (Re)assign the dict object so we have a fresh copy per class
cls.__DUMP_HOOKS__ = {}
[docs]
@classmethod
def register_dump_hook(cls, typ: Type, func: Callable):
"""Registers the hook for a type, on the default dumper by default."""
cls.__DUMP_HOOKS__[typ] = func
[docs]
@classmethod
def get_dump_hook(cls, typ: Type) -> Optional[Callable]:
"""Retrieves the hook for a type, if one exists."""
return cls.__DUMP_HOOKS__.get(typ)
