UID-Related Extras

class properties.extras.HasUID(**kwargs)

HasUID is a HasProperties class that includes unique ID

Adding a UID to HasProperties allows serialization of more complex structures, including recursive self-references. They are serialized to a flat dictionary of UID/HasUID key/value pairs.

Required Properties:

• uid (String): Unique identifier, a unicode string, Default: new instance of str

classmethod deserialize(value, trusted=False, strict=False, assert_valid=False, **kwargs)

Deserialize nested HasUID instance from flat pointer dictionary

Parameters

• value - Flat pointer dictionary produced by serialize with UID/HasUID key/value pairs. It also includes a __root__ key to specify the root HasUID instance.
• trusted - If True (and if the input dictionaries have '__class__' keyword and this class is in the registry), the new HasProperties class will come from the dictionary. If False (the default), only the HasProperties class this method is called on will be constructed.
• strict - Requires '__class__', if present on the input dictionary, to match the deserialized instance’s class. Also disallows unused properties in the input dictionary. Default is False.
• assert_valid - Require deserialized instance to be valid. Default is False.
• You may also specify an alternative root - This allows a different HasUID root instance to be specified. It overrides __root__ in the input dictionary.
• Any other keyword arguments will be passed through to the Property deserializers.

Note

HasUID instances are constructed with no input arguments (ie cls() is called). This means deserialization will fail if the init method has been overridden to require input parameters.

classmethod load(uid)

Load an instance given a UID

This is used by Pointer properties to retrieve instances from UIDs.

serialize(include_class=True, save_dynamic=False, **kwargs)

Serialize nested HasUID instances to a flat dictionary

Parameters:

• include_class - If True (the default), the name of the class will also be saved to the serialized dictionary under key '__class__'
• save_dynamic - If True, dynamic properties are written to the serialized dict (default: False).
• You may also specify a registry - This is the flat dictionary where UID/HasUID pairs are stored. By default, no registry need be provided; a new dictionary will be created.
• Any other keyword arguments will be passed through to the Property serializers.

classmethod validate_uid(uid)

Assert if a given UID is valid

This is used by Pointer properties to validate a UID without necessarily loading the corresponding instance.

class properties.extras.Pointer(doc, instance_class, **kwargs)

Property for HasUID instances where string UID pointer may be used

Available keywords (in addition to those inherited from Instance):

• load - Attempt to load instances from UID on validation If True, when the Pointer property is assigned a valid UID, it will then attempt to call self.instance_class.load(uid) If this method is defined, it must return a valid instance which will replace the UID as the Pointer value. If this method is not defined or if it returns None, the Pointer property maintains the UID value. Default is False, meaning there is no attempt to load the instance.
• uid_prop - Property or attribute name of the UID property on instance_class. The default is ‘uid’.