def dumps(obj: Any,
encoded_type: Type,
skipkeys=False,
ensure_ascii=True,
check_circular=True,
allow_nan=True,
cls=None,
indent=None,
separators=None,
default=None,
sort_keys=False,
**kw) -> str:
# pylint: disable = too-many-arguments
"""
Encodes `obj` as a JSON object using `encoded_type` as a type hint, then calls `json.dumps`.
Raises `TypeError` is `encoded_type` is not JSON-encodable according to `typing_json.encoding.is_json_encodable`.
"""
if not is_json_encodable(encoded_type):
raise TypeError("Type %s is not json-encodable." % str(encoded_type))
json_obj = to_json_obj(obj, encoded_type)
return json.dumps(json_obj,
skipkeys=skipkeys,
ensure_ascii=ensure_ascii,
check_circular=check_circular,
allow_nan=allow_nan,
cls=cls,
indent=indent,
separators=separators,
default=default,
sort_keys=sort_keys,
**kw)
def test_is_json_encodable():
# pylint:disable=line-too-long,missing-docstring,invalid-name
for t in JSON_BASE_TYPES:
assert is_json_encodable(t)
assert is_json_encodable(None)
assert is_json_encodable(...)
class A(NamedTuple):
name: str
value: int
assert is_json_encodable(A)
class B:
# pylint:disable=too-few-public-methods
name: str
value: int
assert not is_json_encodable(B)
type_dict, inherit_dict = make_generic_collection_types(
BASE_TYPES, BASE_TYPES_INHERITANCE)
type_dict, inherit_dict = make_generic_collection_types(
type_dict, inherit_dict)
for t in type_dict:
if contains_non_json_encodable_dict(t):
continue
assert is_json_encodable(t)
type_dict, inherit_dict = make_generic_collection_types(
BASE_TYPES, BASE_TYPES_INHERITANCE)
for t in type_dict:
if t is ... or contains_non_json_encodable_dict(t):
continue
for s in type_dict:
if s is ... or contains_non_json_encodable_dict(s):
continue
assert is_json_encodable(Union[t, s])
assert is_json_encodable(Literal["s", 0, 2, False, None])
assert not is_json_encodable(Literal["s", []]) # type:ignore
assert not is_json_encodable(1.0 + 1.0j)
def loads(s: str,
decoded_type: Type,
cast_decimal: bool = True,
cls=None,
parse_float=Decimal,
parse_int=None,
parse_constant=None,
**kw) -> Any:
# pylint: disable = too-many-arguments
"""
Calls `json.load`, then decodes `obj` from the resulting JSON object using `decoded_type` as a type hint.
Raises `TypeError` is `decoded_type` is not JSON-encodable according to `typing_json.encoding.is_json_encodable`.
"""
if not is_json_encodable(decoded_type):
raise TypeError("Type %s is not json-encodable." % str(decoded_type))
obj = json.loads(s,
cls=cls,
parse_float=parse_float,
parse_int=parse_int,
parse_constant=parse_constant,
object_pairs_hook=collections.OrderedDict,
**kw)
return from_json_obj(obj, decoded_type, cast_decimal=cast_decimal)
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 from_json_obj(obj: Any, t: Any) -> Any:
""" Converts an object of json standard type to json encodable type. """
# pylint:disable=invalid-name,too-many-branches,too-many-statements,too-many-return-statements
if not is_json_encodable(t):
raise TypeError("Type %s is not json-encodable." % str(t))
if t in JSON_BASE_TYPES:
if not isinstance(obj, t):
raise TypeError("Object %s is not %s." % (str(obj), str(t)))
return obj
if t in (None, type(None)):
if obj is not None:
raise TypeError("Object %s is not null (t=%s)." %
(str(obj), str(t)))
return None
if t is ...:
if obj is not None:
raise TypeError("Object %s is not null (t=%s)." %
(str(obj), str(t)))
return ...
if is_namedtuple(t):
if not isinstance(obj, (dict, OrderedDict, list)):
raise TypeError(
"Object %s is not (ordered) dictionary or list (t=%s)." %
(str(obj), str(t))) # pylint:disable=line-too-long
fields = getattr(t, "_fields")
field_types = getattr(t, "_field_types")
field_defaults = getattr(t, "_field_defaults")
if isinstance(obj, list):
if len(fields) != len(obj):
raise TypeError(
"Object %s does not provide the right number of values for a namedtuple."
)
return_val = t(*tuple(
from_json_obj(
obj[i] if i < len(obj) else field_defaults[field],
field_types[field]) for i, field in enumerate(fields))) # pylint:disable=line-too-long
assert is_instance(return_val, t)
return return_val
converted_dict: OrderedDict() = {} # type:ignore
if set(obj.keys()).union(set(field_defaults.keys())) != set(
field_types.keys()):
key_diff = set(obj.keys()).union(set(field_defaults.keys())) - set(
field_types.keys())
if key_diff:
raise TypeError(
"Object %s does not have the required keys: t=%s, extra keys %s."
% (str(obj), str(t), str(key_diff))) # pylint:disable=line-too-long
key_diff = set(field_types.keys()) - set(obj.keys()).union(
set(field_defaults.keys()))
raise TypeError(
"Object %s does not have the required keys: t=%s, missing keys %s."
% (str(obj), str(t), str(key_diff))) # pylint:disable=line-too-long
for field in fields:
field_type = field_types[field]
if not field in obj:
converted_dict[field] = field_defaults[field]
else:
converted_dict[field] = from_json_obj(obj[field], field_type)
return_val = t(**converted_dict)
assert is_instance(return_val, t)
return return_val
if hasattr(t, "__origin__") and hasattr(t, "__args__"): # generics
if t.__origin__ is Union:
for s in t.__args__:
try:
return_val = from_json_obj(obj, s)
assert is_instance(return_val, t)
return return_val
except TypeError:
continue
raise TypeError("Object %s is not convertible to any of %s." %
(str(obj), str(t)))
if t.__origin__ is Literal:
if not is_instance(obj, t):
raise TypeError("Object %s is not allowed (t=%s)." %
(str(obj), str(t)))
return obj
if t.__origin__ is list:
if not isinstance(obj, list):
raise TypeError("Object %s is not list (t=%s)." %
(str(obj), str(t)))
return_val = list(from_json_obj(x, t.__args__[0]) for x in obj)
assert is_instance(return_val, t)
return return_val
if t.__origin__ is deque:
if not isinstance(obj, list):
raise TypeError("Object %s is not list (t=%s)." %
(str(obj), str(t)))
return_val = deque(from_json_obj(x, t.__args__[0]) for x in obj)
assert is_instance(return_val, t)
return return_val
if t.__origin__ is set:
if not isinstance(obj, list):
raise TypeError("Object %s is not list (t=%s)." %
(str(obj), str(t)))
return_val = set(from_json_obj(x, t.__args__[0]) for x in obj)
assert is_instance(return_val, t)
return return_val
if t.__origin__ is frozenset:
if not isinstance(obj, list):
raise TypeError("Object %s is not list (t=%s)." %
(str(obj), str(t)))
return_val = frozenset(
from_json_obj(x, t.__args__[0]) for x in obj)
assert is_instance(return_val, t)
return return_val
if t.__origin__ is tuple:
if not isinstance(obj, list):
raise TypeError("Object %s is not list (t=%s)." %
(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(x, t.__args__[0]) for x in obj)
assert is_instance(return_val, t)
return return_val
else:
if len(obj) != len(t.__args__):
raise TypeError("List %s is of incorrect length (t=%s)." %
(str(obj), str(t)))
return_val = tuple(
from_json_obj(x, t.__args__[i]) for i, x in enumerate(obj))
assert is_instance(return_val, t)
return return_val
if t.__origin__ in (dict, Mapping):
if not isinstance(obj, (dict, OrderedDict)):
raise TypeError(
"Object %s is not dict or OrderedDict (t=%s)." %
(str(obj), str(t)))
converted_dict = dict() # type:ignore
for field in obj:
if not isinstance(field, str):
raise TypeError("Object key %s is string (t=%s)." %
(field, str(t)))
converted_dict[field] = from_json_obj(obj[field],
t.__args__[1])
assert is_instance(converted_dict, t)
return converted_dict
if t.__origin__ is OrderedDict:
if not isinstance(obj, OrderedDict):
raise TypeError(
"Object %s is not dict or OrderedDict (t=%s)." %
(str(obj), str(t)))
converted_dict = OrderedDict() # type:ignore
for field in obj:
if not isinstance(field, str):
raise TypeError("Object key %s is string (t=%s)." %
(field, str(t)))
converted_dict[field] = from_json_obj(obj[field],
t.__args__[1])
assert is_instance(converted_dict, t)
return converted_dict
raise AssertionError(_UNREACHABLE_ERROR_MSG) # pragma: no cover