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.
The same rule applies for frozenset and sets.ImmutableSet.
| Author | Glyph Lefkowitz | |
| Variable | DictTypes | Undocumented |
| Variable | None_atom | Undocumented |
| Variable | class_atom | Undocumented |
| Variable | module_atom | Undocumented |
| Variable | function_atom | Undocumented |
| Variable | dereference_atom | Undocumented |
| Variable | persistent_atom | Undocumented |
| Variable | reference_atom | Undocumented |
| Variable | dictionary_atom | Undocumented |
| Variable | list_atom | Undocumented |
| Variable | set_atom | Undocumented |
| Variable | tuple_atom | Undocumented |
| Variable | instance_atom | Undocumented |
| Variable | frozenset_atom | Undocumented |
| Variable | unpersistable_atom | Undocumented |
| Variable | unjellyableRegistry | Undocumented |
| Variable | unjellyableFactoryRegistry | Undocumented |
| 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'. |
| Variable | globalSecurity | Undocumented |
| Function | jelly | Serialize to s-expression. |
| Function | unjelly | Unserialize from s-expression. |
| Variable | _SetTypes | Undocumented |
| Variable | _ImmutableSetTypes | Undocumented |
| Variable | _sets | Undocumented |
| Function | _createBlank | Given an object, if that object is a type, return a new, blank instance of that type which has not had __init__ called on it. If the object is not a type, return None. |
| Function | _newInstance | Make a new instance of a class without calling its __init__ method. |
| Function | _maybeClass | Undocumented |
| Class | _Jellier | (Internal) This class manages state for a call to jelly() |
| Class | _Unjellier | No class docstring; 0/5 instance variables, 8/29 methods documented |
Given an object, if that object is a type, return a new, blank instance of that type which has not had __init__ called on it. If the object is not a type, return None.
| Parameters | cls | The type (or class) to create an instance of. (type: type or something else that cannot be instantiated.) |
| Returns | a new blank instance or None if cls is not a class or type. | |
Make a new instance of a class without calling its __init__ method.
| Parameters | state | A dict used to update inst.__dict__ either directly or via __setstate__, if available. |
| Returns | A new instance of cls. | |
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', MyCopier).
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.
Set the factory to construct a remote instance of a type:
jellier.setUnjellyableFactoryForClass('module.package.Class', MyFactory)
Call this at the module level immediately after its class definition. copyFactory should return an instance or subclass of RemoteCopy.
Similar to setUnjellyableForClass except it uses a factory instead of creating an instance.
Set all classes in a module derived from baseClass as copiers for a corresponding remote class.
When you have a hierarchy of Copyable (or Cacheable) classes on one side, and a mirror structure of Copied (or RemoteCache) classes on the other, use this to setUnjellyableForClass 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 ''.
| Parameters | module | a module object from which to pull the Copied classes. (passing sys.modules[__name__] might be useful) |
| baseClass | the base class from which all your Copied classes derive. | |
| prefix | the string prefixed to classnames to form the unjellyableRegistry. |
Utility method to default to 'normal' state rules in serialization.
Utility method to default to 'normal' state rules in unserialization.
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.
Unserialize from s-expression.
Takes a 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.