t.s.jelly : module documentation

S-expression-based persistence of python objects.

It does something very much like 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']]]

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]]

The set builtin and the sets.Set class are serialized to the same thing, and unserialized to set if available, else to sets.Set. It means that there's a possibility of type switching in the serialization process. The solution is to always use set if possible, and only use sets.Set under Python 2.3; this can be accomplished by using twisted.python.compat.set.

The same rule applies for frozenset and sets.ImmutableSet.

Author

Glyph Lefkowitz

Function	setUnjellyableForClass	Set which local class will represent a remote type.
Function	setUnjellyableFactoryForClass	Set the factory to construct a remote instance of a type:
Function	setUnjellyableForClassTree	Set all classes in a module derived from baseClass as copiers for a corresponding remote class.
Function	getInstanceState	Utility method to default to 'normal' state rules in serialization.
Function	setInstanceState	Utility method to default to 'normal' state rules in unserialization.
Class	Unpersistable	This is an instance of a class that comes back when something couldn't be unpersisted.
Class	Jellyable	Inherit from me to Jelly yourself directly with the `getStateFor' convenience method.
Class	Unjellyable	Inherit from me to Unjelly yourself directly with the setStateFor convenience method.
Class	InsecureJelly	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.
Class	SecurityOptions	This will by default disallow everything, except for 'none'.
Function	jelly	Serialize to s-expression.
Function	unjelly	Unserialize from s-expression.
Function	_newInstance	Make a new instance of a class without calling its __init__ method. Supports both new- and old-style classes.
Function	_maybeClass	Undocumented
Class	_Jellier	(Internal) This class manages state for a call to jelly()
Class	_Unjellier	No class docstring; 5/27 methods documented
Class	_Dummy	(Internal) Dummy class, used for unserializing instances.
Class	_DummyNewStyle	(Internal) Dummy class, used for unserializing instances of new-style classes.

   jellier.setUnjellyableForClass('module.package.Class', MyCopier).

 jellier.setUnjellyableFactoryForClass('module.package.Class', MyFactory)