"""S-expression-based persistence of python objects.
Stability: semi-stable
Future Plans: Optimization. Lots of optimization. No semantic breakages
should be necessary, but if small tweaks are required to gain acceptable
large-scale performance then they will be made. Although Glyph is the
maintainer, Bruce Mitchener will be supervising most of the optimization work
here.
I do something very much like L{Pickle<pickle>}; however, pickle's main goal
seems to be efficiency (both in space and time); jelly's main goals are
security, human readability, and portability to other environments.
This is how Jelly converts various objects to s-expressions:
Boolean: True --> ['boolean', 'true']
Integer: 1 --> 1
List: [1, 2] --> ['list', 1, 2]
String: \"hello\" --> \"hello\"
Float: 2.3 --> 2.3
Dictionary: {'a' : 1, 'b' : 'c'} --> ['dictionary', ['b', 'c'], ['a', 1]]
Module: UserString --> ['module', 'UserString']
Class: UserString.UserString --> ['class', ['module', 'UserString'], 'UserString']
Function: string.join --> ['function', 'join', ['module', 'string']]
Instance: s is an instance of UserString.UserString, with a __dict__ {'data': 'hello'}:
[\"UserString.UserString\", ['dictionary', ['data', 'hello']]]
# ['instance', ['class', ['module', 'UserString'], 'UserString'], ['dictionary', ['data', 'hello']]]
Class Method: UserString.UserString.center:
['method', 'center', ['None'], ['class', ['module', 'UserString'], 'UserString']]
Instance Method: s.center, where s is an instance of UserString.UserString:
['method', 'center', ['instance', ['reference', 1, ['class', ['module', 'UserString'], 'UserString']], ['dictionary', ['data', 'd']]], ['dereference', 1]]
@author: U{Glyph Lefkowitz<mailto:glyph@twistedmatrix.com>}
"""
__version__ = "$Revision: 1.2 $"[11:-2]
import string
import pickle
import sys
import types
from types import StringType
try:
from types import UnicodeType
except ImportError:
UnicodeType = None
from types import IntType
from types import TupleType
from types import ListType
from types import DictType
from types import LongType
from types import FloatType
from types import FunctionType
from types import MethodType
from types import ModuleType
from types import DictionaryType
from types import InstanceType
from types import NoneType
from types import ClassType
import copy
try:
from types import BooleanType
except ImportError:
BooleanType = None
from new import instance
from new import instancemethod
from twisted.python.reflect import namedObject, namedModule, qual
from twisted.persisted.crefutil import NotKnown, _Tuple, _InstanceMethod, _DictKeyAndValue, _Dereference
from twisted.python import runtime
if runtime.platform.getType() == "java":
from org.python.core import PyStringMap
DictTypes = (DictionaryType, PyStringMap)
else:
DictTypes = (DictionaryType,)
None_atom = "None" class_atom = "class" module_atom = "module" function_atom = "function"
dereference_atom = 'dereference' persistent_atom = 'persistent' reference_atom = 'reference'
dictionary_atom = "dictionary" list_atom = 'list'
tuple_atom = "tuple"
unpersistable_atom = "unpersistable"unjellyableRegistry = {}
unjellyableFactoryRegistry = {}
def _maybeClass(classnamep):
try:
object
except NameError:
isObject = 0
else:
isObject = isinstance(classnamep, type)
if isinstance(classnamep, ClassType) or isObject:
return qual(classnamep)
return classnamep
def setUnjellyableForClass(classname, unjellyable):
"""Set which local class will represent a remote type.
If you have written a Copyable class that you expect your client to be
receiving, write a local "copy" class to represent it, then call::
jellier.setUnjellyableForClass('module.package.Class', MyJellier).
Call this at the module level immediately after its class
definition. MyCopier should be a subclass of RemoteCopy.
The classname may be a special tag returned by
'Copyable.getTypeToCopyFor' rather than an actual classname.
This call is also for cached classes, since there will be no
overlap. The rules are the same.
"""
global unjellyableRegistry
classname = _maybeClass(classname)
unjellyableRegistry[classname] = unjellyable
globalSecurity.allowTypes(classname)
def setUnjellyableFactoryForClass(classname, copyFactory):
"""
Set the factory to construct a remote instance of a type::
jellier.setFactoryForClass('module.package.Class', MyFactory)
Call this at the module level immediately after its class definition.
C{copyFactory} should return an instance or subclass of
L{RemoteCopy<pb.RemoteCopy>}.
Similar to L{setUnjellyableForClass} except it uses a factory instead
of creating an instance.
"""
global unjellyableFactoryRegistry
classname = _maybeClass(classname)
unjellyableFactoryRegistry[classname] = copyFactory
globalSecurity.allowTypes(classname)
def setUnjellyableForClassTree(module, baseClass, prefix=None):
"""
Set all classes in a module derived from C{baseClass} as copiers for
a corresponding remote class.
When you have a heirarchy of Copyable (or Cacheable) classes on
one side, and a mirror structure of Copied (or RemoteCache)
classes on the other, use this to setCopierForClass all your
Copieds for the Copyables.
Each copyTag (the \"classname\" argument to getTypeToCopyFor, and
what the Copyable's getTypeToCopyFor returns) is formed from
adding a prefix to the Copied's class name. The prefix defaults
to module.__name__. If you wish the copy tag to consist of solely
the classname, pass the empty string \'\'.
@param module: a module object from which to pull the Copied classes.
(passing sys.modules[__name__] might be useful)
@param baseClass: the base class from which all your Copied classes derive.
@param prefix: the string prefixed to classnames to form the
unjellyableRegistry.
"""
if prefix is None:
prefix = module.__name__
if prefix:
prefix = "%s." % prefix
for i in dir(module):
i_ = getattr(module, i)
if type(i_) == types.ClassType:
if issubclass(i_, baseClass):
setUnjellyableForClass('%s%s' % (prefix, i), i_)
def getInstanceState(inst, jellier):
"""Utility method to default to 'normal' state rules in serialization.
"""
if hasattr(inst, "__getstate__"):
state = inst.__getstate__()
else:
state = inst.__dict__
sxp = jellier.prepare(inst)
sxp.extend([qual(inst.__class__), jellier.jelly(state)])
return jellier.preserve(inst, sxp)
def setInstanceState(inst, unjellier, jellyList):
"""Utility method to default to 'normal' state rules in unserialization.
"""
state = unjellier.unjelly(jellyList[1])
if hasattr(inst, "__setstate__"):
inst.__setstate__(state)
else:
inst.__dict__ = state
return inst
class Unpersistable:
"""
This is an instance of a class that comes back when something couldn't be
persisted.
"""
def __init__(self, reason):
"""
Initialize an unpersistable object with a descriptive `reason' string.
"""
self.reason = reason
def __repr__(self):
return "Unpersistable(%s)" % repr(self.reason)
class Jellyable:
"""Inherit from me to Jelly yourself directly.
"""
def getStateFor(self, jellier):
return self.__dict__
def jellyFor(self, jellier):
sxp = jellier.prepare(self)
sxp.extend([
qual(self.__class__),
jellier.jelly(self.getStateFor(jellier))])
return jellier.preserve(self, sxp)
class Unjellyable:
"""Inherit from me to Unjelly yourself directly.
"""
def setStateFor(self, unjellier, state):
self.__dict__ = state
def unjellyFor(self, unjellier, jellyList):
state = unjellier.unjelly(jellyList[1])
self.setStateFor(unjellier, state)
class _Jellier:
"""(Internal) This class manages state for a call to jelly()
"""
def __init__(self, taster, persistentStore, invoker):
"""Initialize.
"""
self.taster = taster
self.seen = {} self._ref_id = 0
self.invoker = invoker
constantTypes = {types.StringType : 1, types.IntType : 1,
types.FloatType : 1, types.LongType : 1}
def prepare(self, obj):
return []
def preserve(self, obj, jlist):
return jlist
def _checkMutable(self, obj, refId):
objId = id(obj)
if self.seen.has_key(objId):
objCheck, derefKey = self.seen[objId]
return [dereference_atom, derefKey]
self.seen[objId] = obj, refId
def jelly(self, obj):
if isinstance(obj, Jellyable):
refId = self._ref_id
self._ref_id += 1
preRef = self._checkMutable(obj, refId)
if preRef:
return preRef
return obj.jellyFor(self)
objType = type(obj)
if self.taster.isTypeAllowed(
string.replace(objType.__name__, ' ', '_')):
if ((objType is StringType) or
(objType is IntType) or
(objType is LongType) or
(objType is FloatType)):
return obj
refId = self._ref_id
self._ref_id += 1
if objType is MethodType:
return ["method",
obj.im_func.__name__,
self.jelly(obj.im_self),
self.jelly(obj.im_class)]
elif UnicodeType and objType is UnicodeType:
return ['unicode', obj.encode('UTF-8')]
elif objType is NoneType:
return ['None']
elif objType is FunctionType:
name = obj.__name__
return ['function', str(pickle.whichmodule(obj, obj.__name__))
+ '.' +
name]
elif objType is ModuleType:
return ['module', obj.__name__]
elif objType is BooleanType:
return ['boolean', obj and 'true' or 'false']
elif objType is ClassType or issubclass(objType, type):
return ['class', qual(obj)]
else:
preRef = self._checkMutable(obj, refId)
if preRef:
return preRef
sxp = []
if objType is ListType:
sxp.append(list_atom)
for item in obj:
sxp.append(self.jelly(item))
elif objType is TupleType:
sxp.append(tuple_atom)
for item in obj:
sxp.append(self.jelly(item))
elif objType in DictTypes:
sxp.append(dictionary_atom)
for key, val in obj.items():
self._ref_id += 1
sxp.append([self.jelly(key), self.jelly(val)])
elif objType is InstanceType:
className = qual(obj.__class__)
if self.taster.isClassAllowed(obj.__class__):
sxp.append(className)
if hasattr(obj, "__getstate__"):
state = obj.__getstate__()
else:
state = obj.__dict__
sxp.append(self.jelly(state))
else:
self.unpersistable(
"instance of class %s deemed insecure" %
qual(obj.__class__), sxp)
else:
raise NotImplementedError("Don't know the type: %s" % objType)
return sxp
else:
if objType is types.InstanceType:
raise InsecureJelly("Class not allowed for instance: %s %s" %
(obj.__class__, obj))
raise InsecureJelly("Type not allowed for object: %s %s" %
(objType, obj))
def unpersistable(self, reason, sxp=None):
'''(internal)
Returns an sexp: (unpersistable "reason"). Utility method for making
note that a particular object could not be serialized.
'''
if sxp is None:
sxp = []
sxp.append(unpersistable_atom)
sxp.append(reason)
return sxp
class NullReference(Exception):
"""This object is a marker for when a reference is made to an object
that can't be referenced, i.e.
(tuple (tuple (reference 1)))
"""
_theNullRef = NullReference()
class _Unjellier:
def __init__(self, taster, persistentLoad, invoker):
self.taster = taster
self.references = []
self.postCallbacks = []
self.invoker = invoker
def unjellyFull(self, obj):
o = self.unjelly(obj)
for m in self.postCallbacks:
m()
return o
def unjelly(self, obj):
if type(obj) is not types.ListType:
return obj
self.references.append(_theNullRef)
jelType = obj[0]
if not self.taster.isTypeAllowed(jelType):
raise InsecureJelly(jelType)
regClass = unjellyableRegistry.get(jelType)
if regClass is not None:
if isinstance(regClass, ClassType):
inst = _Dummy() self.resolveReference(inst)
inst.__class__ = regClass
val = inst.unjellyFor(self,obj)
else:
refid = self.getRefId()
self.resolveReference(NotKnown())
val = regClass(self, obj) self.resolveReference(val, refid)
if hasattr(val, 'postUnjelly'):
self.postCallbacks.append(inst.postUnjelly)
return val
regFactory = unjellyableFactoryRegistry.get(jelType)
if regFactory is not None:
refid = self.getRefId()
self.resolveReference(NotKnown())
state = self.unjelly(obj[1])
inst = regFactory(state)
if hasattr(inst, 'postUnjelly'):
self.postCallbacks.append(inst.postUnjelly)
return self.resolveReference(inst, refid)
thunk = getattr(self, '_unjelly_%s'%jelType, None)
if thunk is not None:
ret = thunk(obj[1:])
else:
nameSplit = string.split(jelType, '.')
modName = string.join(nameSplit[:-1], '.')
if not self.taster.isModuleAllowed(modName):
raise InsecureJelly("Module %s not allowed." % modName)
clz = namedObject(jelType)
if not self.taster.isClassAllowed(clz):
raise InsecureJelly("Class %s not allowed." % jelType)
if hasattr(clz, "__setstate__"):
ret = instance(clz, {})
self.resolveReference(ret)
state = self.unjelly(obj[1])
ret.__setstate__(state)
else:
ret = instance(clz, {})
self.resolveReference(ret)
state = self.unjelly(obj[1])
ret.__dict__ = state
if hasattr(clz, 'postUnjelly'):
self.postCallbacks.append(ret.postUnjelly)
return ret
def resolveReference(self, obj, index=-1):
if isinstance(self.references[index], NotKnown):
assert not isinstance(obj, NotKnown)
self.references[index].resolveDependants(obj)
self.references[index] = obj
return obj
def _unjelly_None(self, exp):
return self.resolveReference(None)
def _unjelly_unicode(self, exp):
if UnicodeType:
return self.resolveReference(unicode(exp[0], "UTF-8"))
else:
return self.resolveReference(Unpersistable(exp[0]))
def _unjelly_boolean(self, exp):
if BooleanType:
assert exp[0] in ('true', 'false')
return self.resolveReference(exp[0] == 'true')
else:
return self.resolveReference(Unpersistable(exp[0]))
def unjellyInto(self, obj, loc, jel):
o = self.unjelly(jel)
if isinstance(o, NotKnown):
o.addDependant(obj, loc)
obj[loc] = o
return o
def _unjelly_dereference(self, lst):
refid = lst[0]
return self.references[refid]
def getRefId(self):
return len(self.references) - 1
def _unjelly_tuple(self, lst):
l = [NotKnown()] * len(lst)
result = None
preTuple = _Tuple(l)
refid = self.getRefId()
self.resolveReference(preTuple)
for elem in xrange(len(l)):
self.unjellyInto(preTuple, elem, lst[elem])
if preTuple.resolvedObject is None:
return preTuple
else:
return preTuple.resolvedObject
def _unjelly_list(self, lst):
l = range(len(lst))
self.resolveReference(l)
for elem in l:
self.unjellyInto(l, elem, lst[elem])
return l
def _unjelly_dictionary(self, lst):
d = {}
self.resolveReference(d)
for k, v in lst:
self.references.append(_theNullRef)
kvd = _DictKeyAndValue(d)
self.unjellyInto(kvd, 0, k)
self.unjellyInto(kvd, 1, v)
return d
def _unjelly_module(self, rest):
moduleName = rest[0]
if type(moduleName) != types.StringType:
raise InsecureJelly("Attempted to unjelly a module with a non-string name.")
if not self.taster.isModuleAllowed(moduleName):
raise InsecureJelly("Attempted to unjelly module named %s" % repr(moduleName))
mod = __import__(moduleName, {}, {},"x")
self.resolveReference(mod)
return mod
def _unjelly_class(self, rest):
clist = string.split(rest[0], '.')
modName = string.join(clist[:-1], '.')
if not self.taster.isModuleAllowed(modName):
raise InsecureJelly("module %s not allowed" % modName)
klaus = namedObject(rest[0])
if type(klaus) is not types.ClassType:
raise InsecureJelly("class %s unjellied to something that isn't a class: %s" % (repr(name), repr(klaus)))
if not self.taster.isClassAllowed(klaus):
raise InsecureJelly("class not allowed: %s" % qual(klaus))
self.resolveReference(klaus)
return klaus
def _unjelly_function(self, rest):
modSplit = string.split(rest[0], '.')
modName = string.join(modSplit[:-1], '.')
if not self.taster.isModuleAllowed(modName):
raise InsecureJelly("Module not allowed: %s"% modName)
function = namedObject(rest[0])
self.resolveReference(function)
return function
def _unjelly_unpersistable(self, rest):
return self.resolveReference(Unpersistable(rest[0]))
def _unjelly_method(self, rest):
''' (internal) unjelly a method
'''
nk = NotKnown()
rid = self.getRefId()
self.resolveReference(nk)
im_name = rest[0]
im_self = self.unjelly(rest[1])
im_class = self.unjelly(rest[2])
assert not isinstance(im_self, NotKnown)
if type(im_class) is not types.ClassType:
raise InsecureJelly("Method found with non-class class.")
if im_class.__dict__.has_key(im_name):
if im_self is None:
im = getattr(im_class, im_name)
else:
im = instancemethod(im_class.__dict__[im_name],
im_self,
im_class)
else:
raise 'instance method changed'
return self.resolveReference(im, rid)
class _Dummy:
"""(Internal)
Dummy class, used for unserializing instances.
"""
class InsecureJelly(Exception):
"""
This exception will be raised when a jelly is deemed `insecure'; e.g. it
contains a type, class, or module disallowed by the specified `taster'
"""
class DummySecurityOptions:
"""DummySecurityOptions() -> insecure security options
Dummy security options -- this class will allow anything.
"""
def isModuleAllowed(self, moduleName):
"""DummySecurityOptions.isModuleAllowed(moduleName) -> boolean
returns 1 if a module by that name is allowed, 0 otherwise
"""
return 1
def isClassAllowed(self, klass):
"""DummySecurityOptions.isClassAllowed(class) -> boolean
Assumes the module has already been allowed. Returns 1 if the given
class is allowed, 0 otherwise.
"""
return 1
def isTypeAllowed(self, typeName):
"""DummySecurityOptions.isTypeAllowed(typeName) -> boolean
Returns 1 if the given type is allowed, 0 otherwise.
"""
return 1
class SecurityOptions:
"""
This will by default disallow everything, except for 'none'.
"""
basicTypes = ["dictionary", "list", "tuple",
"reference", "dereference", "unpersistable",
"persistent", "long_int", "long", "dict"]
def __init__(self):
"""SecurityOptions()
Initialize.
"""
self.allowedTypes = {"None": 1,
"bool": 1,
"boolean": 1,
"string": 1,
"str": 1,
"int": 1,
"float": 1,
"NoneType": 1}
if hasattr(types, 'UnicodeType'):
self.allowedTypes['unicode'] = 1
self.allowedModules = {}
self.allowedClasses = {}
def allowBasicTypes(self):
"""SecurityOptions.allowBasicTypes()
Allow all `basic' types. (Dictionary and list. Int, string, and float are implicitly allowed.)
"""
self.allowTypes(*self.basicTypes)
def allowTypes(self, *types):
"""SecurityOptions.allowTypes(typeString): Allow a particular type, by its name.
"""
for typ in types:
self.allowedTypes[string.replace(typ, ' ', '_')]=1
def allowInstancesOf(self, *classes):
"""SecurityOptions.allowInstances(klass, klass, ...): allow instances
of the specified classes
This will also allow the 'instance', 'class' (renamed 'classobj' in
Python 2.3), and 'module' types, as well as basic types.
"""
self.allowBasicTypes()
self.allowTypes("instance", "class", "classobj", "module")
for klass in classes:
self.allowTypes(qual(klass))
self.allowModules(klass.__module__)
self.allowedClasses[klass] = 1
def allowModules(self, *modules):
"""SecurityOptions.allowModules(module, module, ...): allow modules by name
This will also allow the 'module' type.
"""
for module in modules:
if type(module) == types.ModuleType:
module = module.__name__
self.allowedModules[module] = 1
def isModuleAllowed(self, moduleName):
"""SecurityOptions.isModuleAllowed(moduleName) -> boolean
returns 1 if a module by that name is allowed, 0 otherwise
"""
return self.allowedModules.has_key(moduleName)
def isClassAllowed(self, klass):
"""SecurityOptions.isClassAllowed(class) -> boolean
Assumes the module has already been allowed. Returns 1 if the given
class is allowed, 0 otherwise.
"""
return self.allowedClasses.has_key(klass)
def isTypeAllowed(self, typeName):
"""SecurityOptions.isTypeAllowed(typeName) -> boolean
Returns 1 if the given type is allowed, 0 otherwise.
"""
return (self.allowedTypes.has_key(typeName) or
'.' in typeName)
globalSecurity = SecurityOptions()
globalSecurity.allowBasicTypes()
debugCrap = []
def jelly(object, taster = DummySecurityOptions(), persistentStore=None, invoker=None):
"""Serialize to s-expression.
Returns a list which is the serialized representation of an object. An
optional 'taster' argument takes a SecurityOptions and will mark any
insecure objects as unpersistable rather than serializing them.
"""
jr = _Jellier(taster, persistentStore, invoker)
jel = jr.jelly(object)
return jel
def unjelly(sexp, taster = DummySecurityOptions(), persistentLoad=None, invoker=None):
"""Unserialize from s-expression.
Takes an list that was the result from a call to jelly() and unserializes
an arbitrary object from it. The optional 'taster' argument, an instance
of SecurityOptions, will cause an InsecureJelly exception to be raised if a
disallowed type, module, or class attempted to unserialize.
"""
ujr = _Unjellier(taster, persistentLoad, invoker)
result = ujr.unjellyFull(sexp)
return result