379 lines
12 KiB
Python
379 lines
12 KiB
Python
"""Utility methods for marshmallow."""
|
|
|
|
from __future__ import annotations
|
|
|
|
import collections
|
|
import datetime as dt
|
|
import functools
|
|
import inspect
|
|
import json
|
|
import re
|
|
import typing
|
|
import warnings
|
|
from collections.abc import Mapping
|
|
from email.utils import format_datetime, parsedate_to_datetime
|
|
from pprint import pprint as py_pprint
|
|
|
|
from marshmallow.base import FieldABC
|
|
from marshmallow.exceptions import FieldInstanceResolutionError
|
|
from marshmallow.warnings import RemovedInMarshmallow4Warning
|
|
|
|
EXCLUDE = "exclude"
|
|
INCLUDE = "include"
|
|
RAISE = "raise"
|
|
_UNKNOWN_VALUES = {EXCLUDE, INCLUDE, RAISE}
|
|
|
|
|
|
class _Missing:
|
|
def __bool__(self):
|
|
return False
|
|
|
|
def __copy__(self):
|
|
return self
|
|
|
|
def __deepcopy__(self, _):
|
|
return self
|
|
|
|
def __repr__(self):
|
|
return "<marshmallow.missing>"
|
|
|
|
|
|
# Singleton value that indicates that a field's value is missing from input
|
|
# dict passed to :meth:`Schema.load`. If the field's value is not required,
|
|
# it's ``default`` value is used.
|
|
missing = _Missing()
|
|
|
|
|
|
def is_generator(obj) -> bool:
|
|
"""Return True if ``obj`` is a generator"""
|
|
return inspect.isgeneratorfunction(obj) or inspect.isgenerator(obj)
|
|
|
|
|
|
def is_iterable_but_not_string(obj) -> bool:
|
|
"""Return True if ``obj`` is an iterable object that isn't a string."""
|
|
return (hasattr(obj, "__iter__") and not hasattr(obj, "strip")) or is_generator(obj)
|
|
|
|
|
|
def is_collection(obj) -> bool:
|
|
"""Return True if ``obj`` is a collection type, e.g list, tuple, queryset."""
|
|
return is_iterable_but_not_string(obj) and not isinstance(obj, Mapping)
|
|
|
|
|
|
def is_instance_or_subclass(val, class_) -> bool:
|
|
"""Return True if ``val`` is either a subclass or instance of ``class_``."""
|
|
try:
|
|
return issubclass(val, class_)
|
|
except TypeError:
|
|
return isinstance(val, class_)
|
|
|
|
|
|
def is_keyed_tuple(obj) -> bool:
|
|
"""Return True if ``obj`` has keyed tuple behavior, such as
|
|
namedtuples or SQLAlchemy's KeyedTuples.
|
|
"""
|
|
return isinstance(obj, tuple) and hasattr(obj, "_fields")
|
|
|
|
|
|
def pprint(obj, *args, **kwargs) -> None:
|
|
"""Pretty-printing function that can pretty-print OrderedDicts
|
|
like regular dictionaries. Useful for printing the output of
|
|
:meth:`marshmallow.Schema.dump`.
|
|
|
|
.. deprecated:: 3.7.0
|
|
marshmallow.pprint will be removed in marshmallow 4.
|
|
"""
|
|
warnings.warn(
|
|
"marshmallow's pprint function is deprecated and will be removed in marshmallow 4.",
|
|
RemovedInMarshmallow4Warning,
|
|
stacklevel=2,
|
|
)
|
|
if isinstance(obj, collections.OrderedDict):
|
|
print(json.dumps(obj, *args, **kwargs))
|
|
else:
|
|
py_pprint(obj, *args, **kwargs)
|
|
|
|
|
|
# https://stackoverflow.com/a/27596917
|
|
def is_aware(datetime: dt.datetime) -> bool:
|
|
return (
|
|
datetime.tzinfo is not None and datetime.tzinfo.utcoffset(datetime) is not None
|
|
)
|
|
|
|
|
|
def from_rfc(datestring: str) -> dt.datetime:
|
|
"""Parse a RFC822-formatted datetime string and return a datetime object.
|
|
|
|
https://stackoverflow.com/questions/885015/how-to-parse-a-rfc-2822-date-time-into-a-python-datetime # noqa: B950
|
|
"""
|
|
return parsedate_to_datetime(datestring)
|
|
|
|
|
|
def rfcformat(datetime: dt.datetime) -> str:
|
|
"""Return the RFC822-formatted representation of a datetime object.
|
|
|
|
:param datetime datetime: The datetime.
|
|
"""
|
|
return format_datetime(datetime)
|
|
|
|
|
|
# Hat tip to Django for ISO8601 deserialization functions
|
|
|
|
_iso8601_datetime_re = re.compile(
|
|
r"(?P<year>\d{4})-(?P<month>\d{1,2})-(?P<day>\d{1,2})"
|
|
r"[T ](?P<hour>\d{1,2}):(?P<minute>\d{1,2})"
|
|
r"(?::(?P<second>\d{1,2})(?:\.(?P<microsecond>\d{1,6})\d{0,6})?)?"
|
|
r"(?P<tzinfo>Z|[+-]\d{2}(?::?\d{2})?)?$"
|
|
)
|
|
|
|
_iso8601_date_re = re.compile(r"(?P<year>\d{4})-(?P<month>\d{1,2})-(?P<day>\d{1,2})$")
|
|
|
|
_iso8601_time_re = re.compile(
|
|
r"(?P<hour>\d{1,2}):(?P<minute>\d{1,2})"
|
|
r"(?::(?P<second>\d{1,2})(?:\.(?P<microsecond>\d{1,6})\d{0,6})?)?"
|
|
)
|
|
|
|
|
|
def get_fixed_timezone(offset: int | float | dt.timedelta) -> dt.timezone:
|
|
"""Return a tzinfo instance with a fixed offset from UTC."""
|
|
if isinstance(offset, dt.timedelta):
|
|
offset = offset.total_seconds() // 60
|
|
sign = "-" if offset < 0 else "+"
|
|
hhmm = "%02d%02d" % divmod(abs(offset), 60)
|
|
name = sign + hhmm
|
|
return dt.timezone(dt.timedelta(minutes=offset), name)
|
|
|
|
|
|
def from_iso_datetime(value):
|
|
"""Parse a string and return a datetime.datetime.
|
|
|
|
This function supports time zone offsets. When the input contains one,
|
|
the output uses a timezone with a fixed offset from UTC.
|
|
"""
|
|
match = _iso8601_datetime_re.match(value)
|
|
if not match:
|
|
raise ValueError("Not a valid ISO8601-formatted datetime string")
|
|
kw = match.groupdict()
|
|
kw["microsecond"] = kw["microsecond"] and kw["microsecond"].ljust(6, "0")
|
|
tzinfo = kw.pop("tzinfo")
|
|
if tzinfo == "Z":
|
|
tzinfo = dt.timezone.utc
|
|
elif tzinfo is not None:
|
|
offset_mins = int(tzinfo[-2:]) if len(tzinfo) > 3 else 0
|
|
offset = 60 * int(tzinfo[1:3]) + offset_mins
|
|
if tzinfo[0] == "-":
|
|
offset = -offset
|
|
tzinfo = get_fixed_timezone(offset)
|
|
kw = {k: int(v) for k, v in kw.items() if v is not None}
|
|
kw["tzinfo"] = tzinfo
|
|
return dt.datetime(**kw)
|
|
|
|
|
|
def from_iso_time(value):
|
|
"""Parse a string and return a datetime.time.
|
|
|
|
This function doesn't support time zone offsets.
|
|
"""
|
|
match = _iso8601_time_re.match(value)
|
|
if not match:
|
|
raise ValueError("Not a valid ISO8601-formatted time string")
|
|
kw = match.groupdict()
|
|
kw["microsecond"] = kw["microsecond"] and kw["microsecond"].ljust(6, "0")
|
|
kw = {k: int(v) for k, v in kw.items() if v is not None}
|
|
return dt.time(**kw)
|
|
|
|
|
|
def from_iso_date(value):
|
|
"""Parse a string and return a datetime.date."""
|
|
match = _iso8601_date_re.match(value)
|
|
if not match:
|
|
raise ValueError("Not a valid ISO8601-formatted date string")
|
|
kw = {k: int(v) for k, v in match.groupdict().items()}
|
|
return dt.date(**kw)
|
|
|
|
|
|
def from_timestamp(value: typing.Any) -> dt.datetime:
|
|
if value is True or value is False:
|
|
raise ValueError("Not a valid POSIX timestamp")
|
|
value = float(value)
|
|
if value < 0:
|
|
raise ValueError("Not a valid POSIX timestamp")
|
|
|
|
# Load a timestamp with utc as timezone to prevent using system timezone.
|
|
# Then set timezone to None, to let the Field handle adding timezone info.
|
|
try:
|
|
return dt.datetime.fromtimestamp(value, tz=dt.timezone.utc).replace(tzinfo=None)
|
|
except OverflowError as exc:
|
|
raise ValueError("Timestamp is too large") from exc
|
|
except OSError as exc:
|
|
raise ValueError("Error converting value to datetime") from exc
|
|
|
|
|
|
def from_timestamp_ms(value: typing.Any) -> dt.datetime:
|
|
value = float(value)
|
|
return from_timestamp(value / 1000)
|
|
|
|
|
|
def timestamp(
|
|
value: dt.datetime,
|
|
) -> float:
|
|
if not is_aware(value):
|
|
# When a date is naive, use UTC as zone info to prevent using system timezone.
|
|
value = value.replace(tzinfo=dt.timezone.utc)
|
|
return value.timestamp()
|
|
|
|
|
|
def timestamp_ms(value: dt.datetime) -> float:
|
|
return timestamp(value) * 1000
|
|
|
|
|
|
def isoformat(datetime: dt.datetime) -> str:
|
|
"""Return the ISO8601-formatted representation of a datetime object.
|
|
|
|
:param datetime datetime: The datetime.
|
|
"""
|
|
return datetime.isoformat()
|
|
|
|
|
|
def to_iso_time(time: dt.time) -> str:
|
|
return dt.time.isoformat(time)
|
|
|
|
|
|
def to_iso_date(date: dt.date) -> str:
|
|
return dt.date.isoformat(date)
|
|
|
|
|
|
def ensure_text_type(val: str | bytes) -> str:
|
|
if isinstance(val, bytes):
|
|
val = val.decode("utf-8")
|
|
return str(val)
|
|
|
|
|
|
def pluck(dictlist: list[dict[str, typing.Any]], key: str):
|
|
"""Extracts a list of dictionary values from a list of dictionaries.
|
|
::
|
|
|
|
>>> dlist = [{'id': 1, 'name': 'foo'}, {'id': 2, 'name': 'bar'}]
|
|
>>> pluck(dlist, 'id')
|
|
[1, 2]
|
|
"""
|
|
return [d[key] for d in dictlist]
|
|
|
|
|
|
# Various utilities for pulling keyed values from objects
|
|
|
|
|
|
def get_value(obj, key: int | str, default=missing):
|
|
"""Helper for pulling a keyed value off various types of objects. Fields use
|
|
this method by default to access attributes of the source object. For object `x`
|
|
and attribute `i`, this method first tries to access `x[i]`, and then falls back to
|
|
`x.i` if an exception is raised.
|
|
|
|
.. warning::
|
|
If an object `x` does not raise an exception when `x[i]` does not exist,
|
|
`get_value` will never check the value `x.i`. Consider overriding
|
|
`marshmallow.fields.Field.get_value` in this case.
|
|
"""
|
|
if not isinstance(key, int) and "." in key:
|
|
return _get_value_for_keys(obj, key.split("."), default)
|
|
else:
|
|
return _get_value_for_key(obj, key, default)
|
|
|
|
|
|
def _get_value_for_keys(obj, keys, default):
|
|
if len(keys) == 1:
|
|
return _get_value_for_key(obj, keys[0], default)
|
|
else:
|
|
return _get_value_for_keys(
|
|
_get_value_for_key(obj, keys[0], default), keys[1:], default
|
|
)
|
|
|
|
|
|
def _get_value_for_key(obj, key, default):
|
|
if not hasattr(obj, "__getitem__"):
|
|
return getattr(obj, key, default)
|
|
|
|
try:
|
|
return obj[key]
|
|
except (KeyError, IndexError, TypeError, AttributeError):
|
|
return getattr(obj, key, default)
|
|
|
|
|
|
def set_value(dct: dict[str, typing.Any], key: str, value: typing.Any):
|
|
"""Set a value in a dict. If `key` contains a '.', it is assumed
|
|
be a path (i.e. dot-delimited string) to the value's location.
|
|
|
|
::
|
|
|
|
>>> d = {}
|
|
>>> set_value(d, 'foo.bar', 42)
|
|
>>> d
|
|
{'foo': {'bar': 42}}
|
|
"""
|
|
if "." in key:
|
|
head, rest = key.split(".", 1)
|
|
target = dct.setdefault(head, {})
|
|
if not isinstance(target, dict):
|
|
raise ValueError(
|
|
f"Cannot set {key} in {head} " f"due to existing value: {target}"
|
|
)
|
|
set_value(target, rest, value)
|
|
else:
|
|
dct[key] = value
|
|
|
|
|
|
def callable_or_raise(obj):
|
|
"""Check that an object is callable, else raise a :exc:`TypeError`."""
|
|
if not callable(obj):
|
|
raise TypeError(f"Object {obj!r} is not callable.")
|
|
return obj
|
|
|
|
|
|
def _signature(func: typing.Callable) -> list[str]:
|
|
return list(inspect.signature(func).parameters.keys())
|
|
|
|
|
|
def get_func_args(func: typing.Callable) -> list[str]:
|
|
"""Given a callable, return a list of argument names. Handles
|
|
`functools.partial` objects and class-based callables.
|
|
|
|
.. versionchanged:: 3.0.0a1
|
|
Do not return bound arguments, eg. ``self``.
|
|
"""
|
|
if inspect.isfunction(func) or inspect.ismethod(func):
|
|
return _signature(func)
|
|
if isinstance(func, functools.partial):
|
|
return _signature(func.func)
|
|
# Callable class
|
|
return _signature(func)
|
|
|
|
|
|
def resolve_field_instance(cls_or_instance):
|
|
"""Return a Schema instance from a Schema class or instance.
|
|
|
|
:param type|Schema cls_or_instance: Marshmallow Schema class or instance.
|
|
"""
|
|
if isinstance(cls_or_instance, type):
|
|
if not issubclass(cls_or_instance, FieldABC):
|
|
raise FieldInstanceResolutionError
|
|
return cls_or_instance()
|
|
else:
|
|
if not isinstance(cls_or_instance, FieldABC):
|
|
raise FieldInstanceResolutionError
|
|
return cls_or_instance
|
|
|
|
|
|
def timedelta_to_microseconds(value: dt.timedelta) -> int:
|
|
"""Compute the total microseconds of a timedelta
|
|
|
|
https://github.com/python/cpython/blob/bb3e0c240bc60fe08d332ff5955d54197f79751c/Lib/datetime.py#L665-L667 # noqa: B950
|
|
"""
|
|
return (value.days * (24 * 3600) + value.seconds) * 1000000 + value.microseconds
|
|
|
|
|
|
def validate_unknown_parameter_value(obj: typing.Any) -> str:
|
|
if obj not in _UNKNOWN_VALUES:
|
|
raise ValueError(
|
|
f"Object {obj!r} is not a valid value for the 'unknown' parameter"
|
|
)
|
|
return obj
|