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Package twisted :: Package spread :: Module jelly |
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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
Classes | |
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_Dummy |
(Internal) Dummy class, used for unserializing instances. |
_Jellier |
(Internal) This class manages state for a call to jelly() |
_Unjellier |
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DummySecurityOptions |
DummySecurityOptions() -> insecure security options Dummy security options -- this class will allow anything. |
Jellyable |
Inherit from me to Jelly yourself directly with the `getStateFor' convenience method. |
SecurityOptions |
This will by default disallow everything, except for 'none'. |
Unjellyable |
Inherit from me to Unjelly yourself directly with the `setStateFor' convenience method. |
Unpersistable |
This is an instance of a class that comes back when something couldn't be persisted. |
Exceptions | |
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InsecureJelly |
This exception will be raised when a jelly is deemed `insecure'; e.g. |
Function Summary | |
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_maybeClass(classnamep)
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Utility method to default to 'normal' state rules in serialization. | |
Serialize to s-expression. | |
Utility method to default to 'normal' state rules in unserialization. | |
Set the factory to construct a remote instance of a type: | |
Set which local class will represent a remote type. | |
Set all classes in a module derived from baseClass as
copiers for a corresponding remote class. | |
Unserialize from s-expression. |
Variable Summary | |
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str |
__version__ = '1.48'
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SecurityOptions |
globalSecurity = <twisted.spread.jelly.SecurityOptions i...
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dict |
unjellyableFactoryRegistry = {}
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dict |
unjellyableRegistry = {'twisted.web.server.Request': <cl...
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Function Details |
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getInstanceState(inst, jellier)Utility method to default to 'normal' state rules in serialization. |
jelly(object, taster=<twisted.spread.jelly.DummySecurityOptions instance at 0x..., 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. |
setInstanceState(inst, unjellier, jellyList)Utility method to default to 'normal' state rules in unserialization. |
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. setUnjellyableForClass except it uses a
factory instead of creating an instance.
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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. |
setUnjellyableForClassTree(module, baseClass, prefix=None)Set all classes in a module derived from 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 ''.
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unjelly(sexp, taster=<twisted.spread.jelly.DummySecurityOptions instance at 0x..., 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. |
Variable Details |
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__version__
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globalSecurity
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unjellyableFactoryRegistry
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