mitmproxy/mitmproxy/stateobject.py
2020-11-20 19:25:26 +01:00

100 lines
3.3 KiB
Python

import json
import typing
from mitmproxy.coretypes import serializable
from mitmproxy.utils import typecheck
class StateObject(serializable.Serializable):
"""
An object with serializable state.
State attributes can either be serializable types(str, tuple, bool, ...)
or StateObject instances themselves.
"""
_stateobject_attributes: typing.ClassVar[typing.MutableMapping[str, typing.Any]]
"""
An attribute-name -> class-or-type dict containing all attributes that
should be serialized. If the attribute is a class, it must implement the
Serializable protocol.
"""
def get_state(self):
"""
Retrieve object state.
"""
state = {}
for attr, cls in self._stateobject_attributes.items():
val = getattr(self, attr)
state[attr] = get_state(cls, val)
return state
def set_state(self, state):
"""
Load object state from data returned by a get_state call.
"""
state = state.copy()
for attr, cls in self._stateobject_attributes.items():
val = state.pop(attr)
if val is None:
setattr(self, attr, val)
else:
curr = getattr(self, attr, None)
if hasattr(curr, "set_state"):
curr.set_state(val)
else:
setattr(self, attr, make_object(cls, val))
if state:
raise RuntimeWarning(f"Unexpected State in __setstate__: {state}")
def _process(typeinfo: typecheck.Type, val: typing.Any, make: bool) -> typing.Any:
if val is None:
return None
elif make and hasattr(typeinfo, "from_state"):
return typeinfo.from_state(val)
elif not make and hasattr(val, "get_state"):
return val.get_state()
typename = str(typeinfo)
if typename.startswith("typing.List"):
T = typecheck.sequence_type(typeinfo)
return [_process(T, x, make) for x in val]
elif typename.startswith("typing.Tuple"):
Ts = typecheck.tuple_types(typeinfo)
if len(Ts) != len(val):
raise ValueError(f"Invalid data. Expected {Ts}, got {val}.")
return tuple(
_process(T, x, make) for T, x in zip(Ts, val)
)
elif typename.startswith("typing.Dict"):
k_cls, v_cls = typecheck.mapping_types(typeinfo)
return {
_process(k_cls, k, make): _process(v_cls, v, make)
for k, v in val.items()
}
elif typename.startswith("typing.Any"):
# This requires a bit of explanation. We can't import our IO layer here,
# because it causes a circular import. Rather than restructuring the
# code for this, we use JSON serialization, which has similar primitive
# type restrictions as tnetstring, to check for conformance.
try:
json.dumps(val)
except TypeError:
raise ValueError(f"Data not serializable: {val}")
return val
else:
return typeinfo(val)
def make_object(typeinfo: typecheck.Type, val: typing.Any) -> typing.Any:
"""Create an object based on the state given in val."""
return _process(typeinfo, val, True)
def get_state(typeinfo: typecheck.Type, val: typing.Any) -> typing.Any:
"""Get the state of the object given as val."""
return _process(typeinfo, val, False)