def test_is_typed_dict_basic():
"""
Tests that `typing.TypedDict` are identified correctly,
while classes and `dict` are not.
"""
class A(TypedDict):
# pylint:disable=all
name: List[str]
value: Union[int, float]
assert is_typed_dict(A, failure_callback=failure_callback)
a = {"name": ["hi"], "value": 1.1}
assert is_instance(a, A, failure_callback=failure_callback)
a = {"name": 0, "value": 1.1} # type:ignore
assert not is_instance(a, A, failure_callback=failure_callback)
a = {"name": ["hi"], "value": 1.1}
class B:
# pylint:disable=all
name: List[str]
def __init__(self, name: List[str]):
self.name = name
assert not is_typed_dict(0, failure_callback=failure_callback)
assert not is_typed_dict(B, failure_callback=failure_callback)
assert not is_typed_dict(dict, failure_callback=failure_callback)
b = B(["hi"])
assert not is_instance(b, A, failure_callback=failure_callback)
def test_is_typed_dict_fake2():
"""
Tries to make a fake typed dict
"""
class C(dict):
...
assert not is_typed_dict(C, failure_callback=failure_callback)
def test_is_typed_dict_fake4():
"""
Tries to make a fake typed dict
"""
class C(dict):
...
C.__annotations__ = {}
assert not is_typed_dict(C, failure_callback=failure_callback)
def test_is_typed_dict_fake7():
"""
Tries to make a fake typed dict
"""
class C(dict):
...
C.__annotations__ = {10: int}
C.__total__ = True
C.name = "bye"
assert not is_typed_dict(C, failure_callback=failure_callback)
def from_json_obj(obj: Any, t: Type, cast_decimal: bool = True) -> Any:
"""
Decodes a JSON object `obj` into an instance of a typecheckable type `t`.
This method raises `TypeError` if type `t` is not JSON encodable according to `typing_json.encoding.is_json_encodable`.
This method also raises `TypeError` if `obj` is not a valid JSON encoding for an instance of type `t`.
Currently, this method acts as follows on an JSON object `obj` and a JSON-encodable type `t`:
- if `t` is one of the JSON basic types `bool`, `float`, `str`, `NoneType`, `obj` must be an instance of the type an is returned unchanged;
- if `t` is of the JSON basic type `int` and the `cast_decimal` parameter is set to `False`, `obj` must be an instance of `int` and is returned unchanged;
- it `t` is of the JSON basic type `int` and the `cast_decimal` parameter is set to `True` (its default value), `obj` can be either an instance of `int`, in which case it is returned unchanged, or an instance of `decimal.Decimal` encoding an integer, in which case `int(obj)` is returned;
- if `t` is of the JSON basic type `float` and the `cast_decimal` parameter is set to `False`, `obj` must be an instance of `int` or `float`, and `float(obj)` is returned;
- it `t` is of the JSON basic type `float` and the `cast_decimal` parameter is set to `True` (its default value), `obj` can be either an instance of `int`, `float` or `decimal.Decimal`, in which case `float(obj)` is returned;
- if `t` is `None`, used as an alias for `NoneType`, `obj` must be `None` and is returned unchanged;
- if `t` is `decimal.Decimal` and the `cast_decimal` parameter is set to `False`, `obj` must be either a `decimal.Decimal`, an `int` or a `str` encoding a valid decimal, in which case `decimal.Decimal(obj)` is returned;
v- if `t` is `decimal.Decimal` and the `cast_decimal` parameter is set to `True`, `obj` must be either a `decimal.Decimal`, an `int`, a `float` or a `str` encoding a valid decimal, in which case `decimal.Decimal(obj)` is returned;
- if `t` is an enumeration, `obj` must be a key in the dictionary `t.__members__` of names for the enumeration constants, in which case `t.__members__[obj]` is returned;
- if `t` is a namedtuple (according to `typing_json.typechecking.is_namedtuple`), see below;
- if `t` is a namedtuple (according to `typing_json.typechecking.is_typed_dict`), see below;
- if `t` is `typing.Union` or `typing.Optional`, try to decoded `obj` using the generic type arguments one after the other, until a suitable one is found;
- if `t` is `typing_extensions.Literal`, check that `obj` is one of the literals and return it unaltered;
- if `t` is `typing.List`, check that `obj` is a list and return a list with recursively JSON-decoded elements of `obj` in it;
- if `t` is `typing.Tuple`, check that `obj` is a list and return a tuple with recursively JSON-decoded elements of `obj` in it;
- if `t` is `typing.Deque`, check that `obj` is a list and return a deque with recursively JSON-decoded elements of `obj` in it;
- if `t` is `typing.Set`, check that `obj` is a list and return a set with recursively JSON-decoded elements of `obj` in it;
- if `t` is `typing.FrozenSet`, check that `obj` is a list and return a frozenset with recursively JSON-decoded elements of `obj` in it;
- if `t` is `typing.Dict` or `typing.Mapping`, check that `obj` is a dict and return a dict with recursively JSON-decoded keys and values from `obj` (first parsing the keys from strings in all those cases where `typing_json.encoding.to_json_obj` would have stringified them);
- if `t` is `typing.OrderedDict`, check that `obj` is a `collections.OrderedDict` and return a `collections.OrderedDict` with recursively JSON-decoded keys and values from `obj` (first parsing the keys from strings in all those cases where `typing_json.encoding.to_json_obj` would have stringified them);
If `t` is a namedtuple (according to `typing_json.typechecking.is_namedtuple`), `obj` must be a dictionary (not necessarily ordered, although namedtuple are JSON-encoded as such).
The keys for the dictionary must form a subset of all field names for the namedtuple `t`, including at least all names of fields without default value.
An instance of `t` is then constructed (and returned) by assigning to fields having names in the dictionary the JSON decoding of the corresponding values in the dictionary, and to all other fields the default values specified by `t`.
As an exception to the above rule, decoding of namedtuples is allowed from lists of values, in the same order as the namedtuple fields they are to be assigned to.
Missing values are allowed at the end and are filled with default field values.
No excess values are allowed.
This is to support the default `json` library behaviour on namedtuples, encoded as lists of field values.
If `t` is a typed dict (according to `typing_json.typechecking.is_typed_dict`), `obj` must be a dictionary (not necessarily ordered).
The keys for the dictionary must form a subset of all keys for the typed dict `t`; if `t` is total, then all keys must be presend.
An instance of `t` is then constructed (and returned) by assigning to keys having names in the dictionary the JSON decoding of the corresponding values in the dictionary.
(Version 0.1.3)
"""
# pylint: disable = too-many-branches, too-many-statements, too-many-return-statements
trace: List[str] = []
def failure_callback(message: str) -> None:
trace.append(message)
if not is_json_encodable(t, failure_callback=failure_callback):
# Argument `t` must be JSON encodable.
raise TypeError("Type %s is not json-encodable. Trace:\n%s" %
(str(t), "\n".join(trace)))
if t in JSON_BASE_TYPES:
# JSON basic types are returned unaltered, with the exception of casting `Decimal` to `int`/`float` if `cast_decimal` is `True`.
if t == int and cast_decimal and isinstance(
obj, Decimal) and obj == obj.to_integral_value():
return int(obj)
if t == float and cast_decimal and isinstance(obj, Decimal):
return float(obj)
if t == float and isinstance(
obj, int) and obj is not True and obj is not False:
return float(obj)
if not is_instance(obj, t, cast_decimal=cast_decimal):
raise TypeError("Object %s is not of json basic type t=%s." %
(short_str(obj), str(t)))
return obj
if t in (None, type(None)):
# The only value of `NoneType` is `None`, which is returned unaltered.
if obj is not None:
raise TypeError("Object %s is not None (t=%s)." %
(short_str(obj), str(t)))
return None
if t == Decimal:
# Instances of `decimal.Decimal` are decoded from `int` or `string`, as well as from `float` if `cast_decimal` is `True`
try:
if isinstance(
obj,
(int, str, Decimal)) and obj is not True and obj is not False:
return Decimal(obj)
if cast_decimal and isinstance(
obj, float) and obj is not True and obj is not False:
return Decimal(obj)
except InvalidOperation:
...
raise TypeError("Object %s is not decimal.Decimal (t=%s)." %
(short_str(obj), str(t)))
if isinstance(t, EnumMeta):
# For enumerations, use the `t.__members__` dictionary to convert the string name into an enumeration value.
if not isinstance(obj, str):
raise TypeError("Object %s is not a string (t=%s)." %
(short_str(obj), str(t)))
if obj not in t.__members__: # type: ignore
raise TypeError(
"Object %s is not the string of a value of the enum (t=%s)." %
(short_str(obj), str(t)))
return t.__members__[obj] # type: ignore # pylint:disable=protected-access
if is_namedtuple(t):
fields = getattr(t, "_fields")
field_types = getattr(t, "_field_types")
field_defaults = getattr(t, "_field_defaults")
return _from_json_obj_namedtuple(obj,
t,
fields,
field_types,
field_defaults,
cast_decimal=cast_decimal)
if is_typed_dict(t):
# Typed dicts are encoded as ordered dictionaries, with their fields as keys and the JSON-encoded field values as corresponding values.
field_types = getattr(t, "__annotations__")
total = getattr(t, "__total__")
if not isinstance(obj, (dict, OrderedDict)):
raise TypeError("Object %s is not dict or OrderedDict (t=%s)." %
(short_str(obj), str(t)))
converted_dict = dict() # type:ignore
for field, field_type in field_types.items():
if total and field not in obj:
raise TypeError(
"Key %s missing from object %s (typed dict is total, t=%s)"
% (field, short_str(obj), str(t)))
if field in obj:
converted_dict[field] = from_json_obj(
obj[field], field_type, cast_decimal=cast_decimal)
for field in obj:
if field not in field_types:
raise TypeError(
"Extra field %s found when decoding object. (t=%s)." %
(field, str(t)))
return converted_dict
if hasattr(t, "__origin__") and hasattr(t, "__args__"):
# `typing` generics
if t.__origin__ is Union:
# For `typing.Union` (and `typing.Optional`), attempt to decode the value using the generic type arguments in sequence
for s in t.__args__:
try:
return_val = from_json_obj(obj,
s,
cast_decimal=cast_decimal)
# assert is_instance(return_val, t, cast_decimal=cast_decimal)
return return_val
except TypeError:
continue
raise TypeError(
"Object %s is not convertible to any of the types in %s." %
(short_str(obj), str(t)))
if t.__origin__ is Literal:
# for `typing_extensions.Literal`, check that the object is an instance of `t` and then return it unaltered
trace = []
if not is_instance(obj,
t,
failure_callback=failure_callback,
cast_decimal=cast_decimal):
raise TypeError("Object %s is not allowed (t=%s). Trace:\n%s" %
(short_str(obj), str(t), "\n".join(trace)))
return obj
if t.__origin__ is list:
# for `typing.List`, expect a list and return a list with recursively JSON-decoded elements
if not isinstance(obj, list):
raise TypeError("Object %s is not list (t=%s)." %
(short_str(obj), str(t)))
return_val = list(
_from_json_obj_iterator(obj,
t.__args__[0],
cast_decimal=cast_decimal))
# assert is_instance(return_val, t, cast_decimal=cast_decimal)
return return_val
if t.__origin__ is deque:
# for `typing.Deque`, expect a list and return a deque with recursively JSON-decoded elements
if not isinstance(obj, list):
raise TypeError("Object %s is not list (t=%s)." %
(short_str(obj), str(t)))
return_val = deque(
_from_json_obj_iterator(obj,
t.__args__[0],
cast_decimal=cast_decimal))
# assert is_instance(return_val, t, cast_decimal=cast_decimal)
return return_val
if t.__origin__ is set:
# for `typing.Set`, expect a list and return a set with recursively JSON-decoded elements
if not isinstance(obj, list):
raise TypeError("Object %s is not list (t=%s)." %
(short_str(obj), str(t)))
return_val = set(
_from_json_obj_iterator(obj,
t.__args__[0],
cast_decimal=cast_decimal))
# assert is_instance(return_val, t, cast_decimal=cast_decimal)
return return_val
if t.__origin__ is frozenset:
# for `typing.FrozenSet`, expect a list and return a frozenset with recursively JSON-decoded elements
if not isinstance(obj, list):
raise TypeError("Object %s is not list (t=%s)." %
(short_str(obj), str(t)))
return_val = frozenset(
_from_json_obj_iterator(obj,
t.__args__[0],
cast_decimal=cast_decimal))
# assert is_instance(return_val, t, cast_decimal=cast_decimal)
return return_val
if t.__origin__ is tuple:
# for `typing.Tuple`, expect a list and return a tuple with recursively JSON-decoded elements
if not isinstance(obj, list):
raise TypeError("Object %s is not list (t=%s)." %
(short_str(obj), str(t)))
if len(t.__args__) == 2 and t.__args__[1] is ...: # pylint:disable=no-else-return
return_val = tuple(
_from_json_obj_iterator(obj,
t.__args__[0],
cast_decimal=cast_decimal))
# assert is_instance(return_val, t, cast_decimal=cast_decimal)
return return_val
else:
if len(obj) != len(t.__args__):
raise TypeError("List %s is of incorrect length (t=%s)." %
(short_str(obj), str(t)))
return_val = tuple(
from_json_obj(x, t.__args__[i], cast_decimal=cast_decimal)
for i, x in enumerate(obj))
# assert is_instance(return_val, t, cast_decimal=cast_decimal)
return return_val
if t.__origin__ in (dict, Mapping):
# for `typing.Dict` and `typing.Mapping`, expect a dict and return a dict with recursively JSON-decoded values and keys (parsing keys from strings in all those cases where they would have been stringified)
if not isinstance(obj, (dict, OrderedDict)):
raise TypeError(
"Object %s is not dict or OrderedDict (t=%s)." %
(short_str(obj), str(t)))
converted_dict = dict() # type:ignore
for field in obj:
if t.__args__[0] in JSON_BASE_TYPES:
if not is_instance(
field, t.__args__[0], cast_decimal=cast_decimal):
raise TypeError(
"Object key %s is not of json basic type %s (t=%s)."
% (field, str(t.__args__[0]), str(t)))
converted_field = field
elif isinstance(t.__args__[0], EnumMeta) or hasattr(
t.__args__[0],
"__origin__") and t.__args__[0].__origin__ is Literal:
converted_field = from_json_obj(field,
t.__args__[0],
cast_decimal=cast_decimal)
else:
converted_field = from_json_obj(json.loads(field),
t.__args__[0],
cast_decimal=cast_decimal)
converted_dict[converted_field] = from_json_obj(
obj[field], t.__args__[1], cast_decimal=cast_decimal)
# assert is_instance(converted_dict, t, cast_decimal=cast_decimal)
return converted_dict
if t.__origin__ is OrderedDict:
# for `typing.OrderedDict`, expect a `collections.OrderedDict` and return an ordered dict with recursively JSON-decoded values and keys (parsing keys from strings in all those cases where they would have been stringified)
if not isinstance(obj, OrderedDict):
raise TypeError("Object %s is not OrderedDict (t=%s)." %
(short_str(obj), str(t)))
converted_dict = OrderedDict() # type:ignore
for field in obj:
if t.__args__[0] in JSON_BASE_TYPES:
if not isinstance(field, t.__args__[0]):
raise TypeError(
"Object key %s not of json basic type %s (t=%s)." %
(field, str(t.__args__[0]), str(t)))
converted_field = field
elif isinstance(t.__args__[0], EnumMeta) or hasattr(
t.__args__[0],
"__origin__") and t.__args__[0].__origin__ is Literal:
converted_field = from_json_obj(field,
t.__args__[0],
cast_decimal=cast_decimal)
else:
converted_field = from_json_obj(json.loads(field),
t.__args__[0],
cast_decimal=cast_decimal)
converted_dict[converted_field] = from_json_obj(
obj[field], t.__args__[1], cast_decimal=cast_decimal)
# assert is_instance(converted_dict, t, cast_decimal=cast_decimal)
return converted_dict
raise AssertionError(_UNREACHABLE_ERROR_MSG) # pragma: no cover
def is_json_encodable(
t: Type,
failure_callback: Optional[Callable[[str], None]] = None) -> bool:
"""
Checks whether a type `t` can be encoded into JSON (or decoded from JSON) using the `typing_json` library.
The optional parameter `failure_callback` can be used to collect a detailed trace of
the reasons behind this method returning `False` on a given type `t`.
Currently, a type `t` is JSON encodable according to this method if it is typecheckable according to
`typing_json.typechecking.is_typecheckable` and it satisfies one of the following conditions:
- if `t` is one of the JSON basic types `bool`, `int`, `float`, `str`, `NoneType`;
- if `t` is a `decimal.Decimal`;
- if `t` is `None` (used as an alias for `NoneType`);
- if `t` is an enum (i.e. `isinstance(t, EnumMeta)`);
- if `t` is a namedtuple according to `typing_json.typechecking.is_namedtuple` and all its fields are JSON encodable;
- if `t` is a typed dictionary according to `typing_json.typechecking.is_typed_dict` and all its values are JSON encodable;
- if `t` is one of `typing.List`, `typing.Set`, `typing.FrozenSet`, `typing.Deque`, `typing.Optional` or a variadic `typing.Tuple` and its generic type argument is JSON encodable;
- if `t` is a `typing.Union` or a fixed-length `typing.Tuple` and all of its generic type arguments are JSON encodable;
- if `t` is a `typing.Dict`, `typing.OrderedDict` or `typing.Mapping`, its generic key type is keyable (according to `typing_json.typechecking.is_keyable`) and both its generic key and value types are JSON encodable;
- if `t` is a `typing_extensions.Literal` and all of its literal arguments are of JSON basic type.
(Version 0.1.3)
"""
# pylint: disable = too-many-return-statements, too-many-branches
if not is_typecheckable(t, failure_callback=failure_callback):
# only typecheckable types are encodable
return _not_json_encodable("Type %s is not typecheckable." % str(t),
failure_callback=failure_callback)
if t in JSON_BASE_TYPES:
# JSON basic types are encodable
return True
if t is Decimal:
# `decimal.Decimal` is encodable
return True
if t is None:
# `None` canbe used as an alias for class `NoneType`
return True
if isinstance(t, EnumMeta):
# enums are encodable
return True
if is_namedtuple(t):
field_types = getattr(t, "_field_types")
if all(
is_json_encodable(field_types[field],
failure_callback=failure_callback)
for field in field_types):
# namedtuples are encodable if all their fields are of encodable types
return True
return _not_json_encodable(
"Not all fields of namedtuple %s are json-encodable." % str(t),
failure_callback=failure_callback)
if is_typed_dict(t):
field_types = getattr(t, "__annotations__")
if all(
is_json_encodable(field_types[field],
failure_callback=failure_callback)
for field in field_types):
# typed dicts are encodable if all their fields are of encodable types
return True
return _not_json_encodable(
"Not all fields of typed dict %s are json-encodable." % str(t),
failure_callback=failure_callback)
if hasattr(t, "__origin__") and hasattr(t, "__args__"):
# `typing` generics
if t.__origin__ in (list, set, frozenset, deque, Optional):
if is_json_encodable(t.__args__[0],
failure_callback=failure_callback):
# `typing.List`, `typing.Set`, `typing.FrozenSet`, `typing.Deque` and `typing.Optional` are encodable if their generic type argument is encodable
return True
return _not_json_encodable(
"Type of elements in %s is not json-encodable." % str(t),
failure_callback=failure_callback)
if t.__origin__ is tuple:
# `typing.Tuple`
if len(t.__args__) == 2 and t.__args__[1] is ...: # pylint:disable=no-else-return
if is_json_encodable(t.__args__[0],
failure_callback=failure_callback):
# variadic `typing.Tuple` are encodable if their generic type argument is encodable
return True
return _not_json_encodable(
"Type of elements in %s is not json-encodable." % str(t),
failure_callback=failure_callback)
else:
if all(
is_json_encodable(s, failure_callback=failure_callback)
for s in t.__args__):
# fixed-length `typing.Tuple` are encodable if all their generic type arguments are encodable
return True
return _not_json_encodable(
"Type of some element in %s is not json-encodable." %
str(t),
failure_callback=failure_callback)
if t.__origin__ is Union:
if all(
is_json_encodable(s, failure_callback=failure_callback)
for s in t.__args__):
# `typing.Union` are encodable if all their generic type arguments are encodable
return True
return _not_json_encodable(
"Some type in %s is not json-encodable." % str(t),
failure_callback=failure_callback)
if t.__origin__ in (dict, OrderedDict, Mapping):
# `typing.Dict`, `typing.OrderedDict` and `typing.Mapping` are encodable if their generic key and value types are encodable and their key type is keyable
if not is_keyable(t.__args__[0],
failure_callback=failure_callback):
return _not_json_encodable(
"Type of keys in %s is not keyable." % str(t),
failure_callback=failure_callback)
if not is_json_encodable(t.__args__[0],
failure_callback=failure_callback):
return _not_json_encodable(
"Type of keys in %s is not json-encodable." % str(t),
failure_callback=failure_callback)
if not is_json_encodable(t.__args__[1],
failure_callback=failure_callback):
return _not_json_encodable(
"Type of values in %s is not json-encodable." % str(t),
failure_callback=failure_callback)
return True
if t.__origin__ is Literal:
# `typing_extensions.Literal` are encodable as long as their literals are JSON basic types, which is always the case if they are typecheckable.
return True
return False
def to_json_obj(obj: Any,
t: Type,
use_decimal: bool = False,
typecheck: bool = True,
namedtuples_as_lists=False) -> Any:
"""
Encodes an instance `obj` of typecheckable type `t` into a JSON object.
The optional `use_decimal` parameter can be used to specify that instances of
`decimal.Decimal` can be used in the output: if `False`, they are converted to strings.
This method raises `TypeError` if type `t` is not typecheckable according to `typing_json.typechecking.is_typecheckable`.
This method raises `TypeError` if `obj` is not of type `t` according to `typing_json.typechecking.is_instance`.
Currently, this method acts as follows on an instance `obj` of type `t`:
- if `t` is one of the JSON basic types `bool`, `int`, `float`, `str`, `NoneType`, the instance `obj` is returned unchanged;
- if `t` is `decimal.Decimal` and `use_decimal` is `False` (default), `str(obj)` is returned;
- if `t` is `decimal.Decimal` and `use_decimal` is `True`, `obj` is returned unchanged;
- if `t` is `None` (used as an alias for `NoneType`), `None` is returned;
- if `t` is an enum (i.e. `isinstance(t, EnumMeta)`), the enum value name `obj._name_` is returned;
- if `t` is a namedtuple according to `typing_json.typechecking.is_namedtuple` and all its fields are JSON encodable and `namedtuples_as_lists` is `False`, this method is called recursively on all field values and then an ordered dictionary is returned with the field names as names and the JSON-encoded field values as corresponding values;
- if `t` is a namedtuple according to `typing_json.typechecking.is_namedtuple` and all its fields are JSON encodable and `namedtuples_as_lists` is `True`, this method is called recursively on all field values and then a list is returned with the JSON-encoded field values appearing in the same order as the namedtuple fields (which are not explicitly encoded);
- if `t` is a typed dict according to `typing_json.typechecking.is_typed_dict` and all its values are JSON encodable, then a dictionary is returned with the same keys as `obj` and JSON-encoded values using the types specified by `t`.
- if `t` is `typing.Union`, the generic type arguments in the union are tried one after the other until a `u` is found such that `is_instance(obj, u)`, then `obj` is JSON-encoded using `u` as its type.
- if `t` is a `typing_extensions.Literal`, `obj` is returned unchanged;
- if `t` is one of `typing.List`, `typing.Set`, `typing.FrozenSet`, `typing.Deque` or `typing.Tuple`, a list is returned containing the elements of the original collection, recursively JSON-encoded;
- if `t` is a `typing.Dict` or `typing.Mapping`, a dictionary (`dict`) is returned with JSON-encoded values from the original dictionary/mapping, associated to either then JSON-encoded keys or a stringified version of the JSON-encoded keys (cf. below);
- if `t` is `typing.OrderedDict`, an ordered dictionary (`collections.OrderedDict`) is returned with JSON-encoded values from the original dictionary/mapping, associated to either then JSON-encoded keys or a stringified version of the JSON-encoded keys (cf. below).
In the case of dictionaries, it is not necessarily the case keys will be compatible with the JSON specification in their JSON-encoded form.
When encoding dictionaries, the keys used in the encoding follow the following criteria:
- if the key type is a JOSN basic type, `decimal.Decimal` or an enumeration type, the JSON encoding of the keys is used;
- otherwise, the stringified version of the JSON encoding (using `json.dumps`) is used;
Literals can only be of JSON basic type.
An optional parameter `typecheck` (default: `True`) can be used to skip the check that `t` be JSON encodable and that `obj` be an instance of `t`.
The parameter `typecheck` is set to `False` in all recursive calls (i.e. typechecking is only done once).
(Version 0.1.3)
"""
# pylint:disable=invalid-name,too-many-return-statements,too-many-branches
if typecheck:
trace: List[str] = []
def failure_callback(message: str) -> None:
trace.append(message)
if not is_json_encodable(t, failure_callback=failure_callback):
# Argument `t` must be JSON encodable.
raise TypeError("Type %s is not json-encodable. Trace:\n%s" %
(str(t), "\n".join(trace)))
trace = []
if not is_instance(obj, t, failure_callback=failure_callback):
# Argument `obj` must be an instance of argument `t`.
raise TypeError("Object %s is not of type %s. Trace:\n%s" %
(short_str(obj), str(t), "\n".join(trace)))
if t in JSON_BASE_TYPES:
# JSON basic types are returned unchanged.
return obj
if t is Decimal:
# If `use_decimal` is `True`, `obj` is returned unchanged:
if use_decimal:
return obj
# If `use_decimal` is `False` (default), instances of `decimal.Decimal` are encoded as strings.
return str(obj)
if t in (None, type(None)):
# `None` can be used as an alias for `NoneType`.
return None
if isinstance(t, EnumMeta):
# Enum values are encoded by their name.
return obj._name_ # pylint:disable=protected-access
if is_namedtuple(t):
# Namedtuples are encoded as ordered dictionaries, with their fields as keys and the JSON-encoded field values as corresponding values.
field_types = getattr(t, "_field_types")
return _to_json_obj_namedtuple(
obj,
field_types,
use_decimal=use_decimal,
namedtuples_as_lists=namedtuples_as_lists)
if is_typed_dict(t):
# Typed dicts are encoded as ordered dictionaries, with their fields as keys and the JSON-encoded field values as corresponding values.
field_types = getattr(t, "__annotations__")
# return _to_json_obj_namedtuple(obj, field_types, use_decimal=use_decimal, namedtuples_as_lists=namedtuples_as_lists)
# A `dict`is used for `typing.Dict` and `typing.Mapping`.
return {
field: to_json_obj(obj[field],
field_type,
use_decimal=use_decimal,
typecheck=False,
namedtuples_as_lists=namedtuples_as_lists)
for field, field_type in field_types.items()
}
if hasattr(t, "__origin__") and hasattr(t, "__args__"):
# Generics from the `typing` module.
if t.__origin__ is Union:
# values in a `typing.Union` are JSON-encoded using the first type in the union that the object is found to be an instance of.
for s in t.__args__:
if is_instance(obj, s):
return to_json_obj(
obj,
s,
use_decimal=use_decimal,
typecheck=False,
namedtuples_as_lists=namedtuples_as_lists)
raise AssertionError(_UNREACHABLE_ERROR_MSG) # pragma: no cover
if t.__origin__ is Literal:
# `typing_extensions.Literal` are returned unchanged
return obj
if t.__origin__ in (list, set, frozenset, deque):
# `typing.List`, `typing.Set`, `typing.FrozenSet` and `typing.Deque` are turned into lists, with their elements recursively JSON-encoded
return _to_json_obj_homogeneous_collection(
obj,
t.__args__[0],
use_decimal=use_decimal,
namedtuples_as_lists=namedtuples_as_lists)
if t.__origin__ is tuple:
# `typing.Tuple` are turned into lists, with their elements recursively JSON-encoded
if len(t.__args__) == 2 and t.__args__[1] is ...: # pylint:disable=no-else-return
return _to_json_obj_homogeneous_collection(
obj,
t.__args__[0],
use_decimal=use_decimal,
namedtuples_as_lists=namedtuples_as_lists)
else:
return [
to_json_obj(x,
t.__args__[i],
use_decimal=use_decimal,
typecheck=False,
namedtuples_as_lists=namedtuples_as_lists)
for i, x in enumerate(obj)
]
if t.__origin__ in (dict, OrderedDict, Mapping):
# `typing.Dict` and `typing.Mapping` are turned into dictionaries and `typing.OrderedDict` are turned into ordered dictionaries.
# The values are recursively JSON-encoded. Keys require special handling.
fields = [field for field in obj
] # pylint: disable = unnecessary-comprehension
if t.__args__[0] in JSON_BASE_TYPES + (
Decimal,
None,
):
# Keys of JSON basic types, `decimal.Decimal` and `None` are recursively JSON-encoded.
# encoded_fields = [field for field in fields] # pylint: disable = unnecessary-comprehension
encoded_fields = [
to_json_obj(field,
t.__args__[0],
use_decimal=use_decimal,
typecheck=False,
namedtuples_as_lists=namedtuples_as_lists)
for field in fields
]
elif (hasattr(t.__args__[0], "__origin__")
and t.__args__[0].__origin__ is Literal):
# Keys of `typing_extensions.Literal` types are recursively JSON-encoded.
# encoded_fields = [field for field in fields] # pylint: disable = unnecessary-comprehension
encoded_fields = [
to_json_obj(field,
t.__args__[0],
use_decimal=use_decimal,
typecheck=False,
namedtuples_as_lists=namedtuples_as_lists)
for field in fields
]
elif isinstance(t.__args__[0], EnumMeta):
# Keys of enumeration types are recursively JSON-encoded.
encoded_fields = [
to_json_obj(field,
t.__args__[0],
use_decimal=use_decimal,
typecheck=False,
namedtuples_as_lists=namedtuples_as_lists)
for field in fields
]
else:
# Keys of any other type are recursively JSON-encoded and then JSON dumped to strings.
encoded_fields = [
json.dumps(
to_json_obj(field,
t.__args__[0],
use_decimal=use_decimal,
typecheck=False,
namedtuples_as_lists=namedtuples_as_lists))
for field in fields
]
if t.__origin__ in (dict, Mapping):
# A `dict`is used for `typing.Dict` and `typing.Mapping`.
return {
encoded_fields[i]:
to_json_obj(obj[field],
t.__args__[1],
use_decimal=use_decimal,
typecheck=False,
namedtuples_as_lists=namedtuples_as_lists)
for i, field in enumerate(fields)
}
if t.__origin__ is OrderedDict:
# A `collections.OrderedDict` is used for `typing.OrderedDict`.
new_ordered_dict = OrderedDict() # type:ignore
for i, field in enumerate(fields):
new_ordered_dict[encoded_fields[i]] = to_json_obj(
obj[field],
t.__args__[1],
use_decimal=use_decimal,
typecheck=False,
namedtuples_as_lists=namedtuples_as_lists)
return new_ordered_dict
raise AssertionError(_UNREACHABLE_ERROR_MSG) # pragma: no cover
