Part of twisted.spread View Source
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 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 | Glyph Lefkowitz | |
| Function | _newInstance | Make a new instance of a class without calling its __init__ method. |
| Function | _maybeClass | 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
|
| 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 |
| Class | Jellyable | Inherit from me to Jelly yourself directly with the `getStateFor' |
| Class | Unjellyable | Inherit from me to Unjelly yourself directly with the |
| Class | _Jellier | (Internal) This class manages state for a call to jelly() |
| Class | _Unjellier | No class docstring; 1/23 methods documented |
| Class | _Dummy | (Internal) |
| Class | _DummyNewStyle | (Internal) |
| Class | InsecureJelly | This exception will be raised when a jelly is deemed `insecure'; e.g. it |
| Class | DummySecurityOptions | DummySecurityOptions() -> insecure security options |
| Class | SecurityOptions | This will by default disallow everything, except for 'none'. |
| Function | jelly | Serialize to s-expression. |
| Function | unjelly | Unserialize from s-expression. |
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.
jellier.setFactoryForClass('module.package.Class', MyFactory)
Call this at the module level immediately after its class definition.
copyFactory should return an instance or subclass of
RemoteCopy.
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 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 ''.| 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. |
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 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.