Maybe try this code. First you will have to pad your file (with zeros) to be at least the original size, can be more (or maybe you can change some code to make this not necessary).
I modified the function _Unpickler.load() to not terminate at exceptions and to return its stack if the unpickling fails. The stack seems to be a list with the names and values of the attributes, so using setattr() you can assign them to a created object.
My example creates an object to pickle if read=False and unpickles the potentially corrupted file if read=True.
import pickle
read = False # run once with False, then corrupt file and change to True
class AClass:
def __init__(unpickler, a, b, c):
unpickler.a = a
unpickler.b = b
unpickler.c = c
def load(unpickler):
"""Read a pickled object representation from the open file.
Return the reconstituted object hierarchy specified in the file.
"""
# Check whether Unpickler was initialized correctly. This is
# only needed to mimic the behavior of _pickle.Unpickler.dump().
if not hasattr(unpickler, "_file_read"):
raise pickle.UnpicklingError("Unpickler.__init__() was not called by "
"%s.__init__()" % (unpickler.__class__.__name__,))
unpickler._unframer = pickle._Unframer(unpickler._file_read, unpickler._file_readline)
unpickler.read = unpickler._unframer.read
unpickler.readline = unpickler._unframer.readline
unpickler.metastack = []
unpickler.stack = []
unpickler.append = unpickler.stack.append
unpickler.proto = 0
read = unpickler.read
dispatch = unpickler.dispatch
try:
while True:
key = read(1)
if not key:
return unpickler.stack
#raise EOFError
assert isinstance(key, pickle.bytes_types)
try:
dispatch[key[0]](unpickler)
except KeyError as e:
print("KeyError")
#dispatch[NONE[0]](unpickler)
except ValueError as e:
print("ValueError")
except pickle._Stop as stopinst:
print("Stop raised")
print(stopinst.value)
return stopinst.value
if not read:
# create an object and save it
obj = AClass(1,2,3)
with open("obj.pkl", 'wb') as outFile:
pickle.dump(obj, outFile, pickle.HIGHEST_PROTOCOL)
else:
# open the object
with (open("obj.pkl", "rb")) as inFile:
try:
unpickler = pickle._Unpickler(inFile)
obj = load(unpickler)
except Exception as e:
print(e)
# a list will be returned, if the unpickling fails
if isinstance(obj, list):
l = obj
print(l)
i = 0
obj = AClass(0,0,0)
while i < len(l)-1:
setattr(obj, l[i], l[i+1])
i += 2
print(obj.a, obj.b, obj.c)
