===============================
Desert: DRY deserialization
Desert generates serialization schemas for dataclasses
and attrs
classes. Writing
code that's DRY ("don't repeat yourself") helps avoid bugs and improve readability. Desert
helps you write code that's DRY.
Installation
::
pip install desert
or with Poetry
_
::
poetry add desert
Usage
..
start-basic-usage
A simple example models two Person
objects in a Car
.
.. code-block:: python
from dataclasses import dataclass
# Or using attrs
# from attr import dataclass
from typing import List
import desert
@dataclass
class Person:
name: str
age: int
@dataclass
class Car:
passengers: List[Person]
# Load some simple data types.
data = {'passengers': [{'name': 'Alice', 'age': 21}, {'name': 'Bob', 'age': 22}]}
# Create a schema for the Car class.
schema = desert.schema(Car)
# Load the data.
car = schema.load(data)
assert car == Car(passengers=[Person(name='Alice', age=21), Person(name='Bob', age=22)])
..
end-basic-usage
Documentation
https://desert.readthedocs.io/
Limitations
String annotations and forward references inside of functions are not supported.
Acknowledgements
- This package began as an extension of marshmallow-dataclass_ to add support for attrs_.
.. _Poetry: https://poetry.eustace.io
.. _marshmallow-dataclass: https://pypi.org/project/marshmallow-dataclass/
.. _attrs: http://www.attrs.org/
2022.09.22 (2022-09-22)
Backward-incompatible Changes
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
- Update all project dependencies and fix all deprecated warnings. Python 3.6
support was dropped to allow updating deprecated dependencies.
#161 <https://github.com/python-desert/desert/issues/161>
_
Changes
^^^^^^^
-
It is now possible to use type-variant generics
_ in your dataclasses, such as Sequence
or MutableSequence
instead of List
, Mapping
instead of Dict
, etc.
This allows you to hide implementation details from users of your dataclasses. If a field
in your dataclass works just as fine with a tuple as a list, you no longer need to force
your users to pass in a list
just to satisfy type checkers.
For example, by using Mapping
or MutableMapping
, users can pass OrderedDict
to
a Dict
attribute without MyPy complaining.
.. code-block:: python
@dataclass
class OldWay:
str_list: List[str]
num_map: Dict[str, float]
# MyPy will reject this even though Marshmallow works just fine. If you use
# type-variant generics, MyPy will accept this code.
instance = OldClass([], collections.ChainMap(MY_DEFAULTS))
@dataclass
class NewWay:
str_list: List[str] # Type-invariants still work
num_map: MutableMapping[str, float] # Now generics do too
.. _type-variant generics: https://mypy.readthedocs.io/en/stable/generics.html
#140 <https://github.com/python-desert/desert/issues/140>
_
2020.11.18 (2020-11-18)
Changes
^^^^^^^
- Schemas no longer copy non-field dataclass attributes. Thanks to @sveinse for report and test.
#79 <https://github.com/python-desert/desert/issues/79>
_
2020.01.06 (2020-01-06)
Changes
^^^^^^^
- Additional metadata are supported in ib() and fields(). Thanks to @sveinse for reporting and testing.
#28 <https://github.com/python-desert/desert/issues/28>
_
2020.01.05 (2020-01-05)
Changes
^^^^^^^
- Add support for attrs factories that take
self
(attr.Factory(..., takes_self=True)
).
#27 <https://github.com/python-desert/desert/issues/27>
_
2020.01.04 (2020-01-04)
Changes
^^^^^^^
- Add support for Tuple[int, ...] per https://docs.python.org/3/library/typing.html#typing.Tuple
#16 <https://github.com/python-desert/desert/issues/16>
_ Thanks to @sveinse for reporting and testing. - Use module imports internally.
#18 <https://github.com/python-desert/desert/issues/18>
_ - Desert version only needs to be updated in version.py
#19 <https://github.com/python-desert/desert/issues/19>
- Fix doctests.
#20 <https://github.com/python-desert/desert/issues/20>
_
2020.01.03
Changes
^^^^^^^^
Optional
fields allow None
. #11 <https://github.com/python-desert/desert/issues/11>
__. Thanks to @sveinse for reporting and testing.
2019.12.18
Changes
^^^^^^^
- Improve error message for unknown generics.
#10 <https://github.com/python-desert/desert/pull/10>
_
2019.12.10
Changes
^^^^^^^
- Add
UnknownType
exception with better error message for types that should be generic.
#8 <https://github.com/python-desert/desert/issues/8>
_
2019.12.09
Changes
^^^^^^^
- Marshmallow schema
Meta
arguments are accepted, allowing exclusion of unknown fields and other options.
#3 <https://github.com/python-desert/desert/pull/3>
_
2019.11.06 (2019-11-06)
Changes
^^^^^^^
- Add twine and wheel development dependencies.
#2 <https://github.com/python-desert/desert/issues/2>
_
2019.11.06 (2019-11-06)
Changes
^^^^^^^
Backward-incompatible Changes
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
- Non-optional fields without a default or factory now have
required=True
so raise marshmallow.exceptions.ValidationError
when missing.
#1 <https://github.com/python-desert/desert/issues/1>
_
0.1.0 (2019-06-22)
Changes
^^^^^^^