2.2. fancytypes.PreSerializable

class PreSerializable(params_to_be_mapped_to_core_attrs={}, validation_and_conversion_funcs={}, pre_serialization_funcs={}, de_pre_serialization_funcs={}, skip_validation_and_conversion=False)

Bases: Checkable

A type that is pre-serializable, that can be constructed from a serializable representation, and that can perform user-defined validations and conversions of a set of parameters upon construction.

We define pre-serialization as the process of converting an object into a form that can be subsequently serialized into a JSON format. We refer to objects resulting from pre-serialization as serializable objects.

We define de-pre-serialization as the process of converting a serializable object into an instance of the type fancytypes.PreSerializable or a subclass thereof, i.e. de-pre-serialization is the reverse process of pre-serialization.

Parameters:

• validation_and_conversion_funcs (dict, optional) – A dict object of callable objects.

• pre_serialization_funcs (dict, optional) –

  A dict object of callable objects that has the same keys as validation_and_conversion_funcs.

  Let core_attrs_candidate_1 be any dict object that has a key set that is any subset key_subset of that of validation_and_conversion_funcs, where for each dict key key in core_attrs_candidate_1, validation_and_conversion_funcs[key](core_attrs_candidate_1) does not raise an exception.

  For each dict key key in core_attrs_candidate_1, pre_serialization_funcs[key](core_attrs_candidate_1[key]) is expected to yield a serializable object, i.e. it should yield an object that can be passed into the function json.dumps without raising an exception.

• de_pre_serialization_funcs (dict, optional) –

  A dict object of callable objects that has the same keys as validation_and_conversion_funcs.

  Let core_attrs_candidate_1 be as defined in the above description of pre_serialization_funcs.

  Let serializable_rep be a dict object that has the same keys as core_attrs_candidate_1, where for each dict key key in validation_and_conversion_funcs, serializable_rep[key] is set to pre_serialization_funcs[key](core_attrs_candidate_1[key]).

  The items of de_pre_serialization_funcs are expected to be set to callable objects that would lead to de_pre_serialization_funcs[key](serializable_rep[key]) not raising an exception for each dict key key in serializable_rep.

  Let core_attrs_candidate_2 be a dict object that has the same keys as serializable_rep, where for each dict key key in validation_and_conversion_funcs, core_attrs_candidate_2[key] is set to de_pre_serialization_funcs[key](serializable_rep[key]).

  The items of de_pre_serialization_funcs are also expected to be set to callable objects that would lead to validation_and_conversion_funcs[key](core_attrs_candidate_2) not raising an exception for each dict key key in core_attrs_candidate_2.

• params_to_be_mapped_to_core_attrs (dict, optional) – A dict object that has the same keys as core_attrs_candidate_1, where core_attrs_candidate_1 was defined in the above description of pre_serialization_funcs.

• skip_validation_and_conversion (bool, optional) –

  Let core_attrs denote the attribute fancytypes.PreSerializable.core_attrs, which is a dict object.

  If skip_validation_and_conversion is set to False, then for each key key in params_to_be_mapped_to_core_attrs, core_attrs[key] is set to validation_and_conversion_funcs[key] (params_to_be_mapped_to_core_attrs).

  Otherwise, if skip_validation_and_conversion is set to True, then core_attrs is set to params_to_be_mapped_to_core_attrs. This option is desired primarily when the user wants to avoid potentially expensive copies and/or conversions of the dict values of params_to_be_mapped_to_core_attrs, as it is guaranteed that no copies or conversions are made in this case.

validation_and_conversion_funcs

Same as the constructor parameter of the same name.

Type:

dict, read-only

pre_serialization_funcs

Same as the constructor parameter of the same name.

Type:

dict, read-only

de_pre_serialization_funcs

Same as the constructor parameter of the same name.

Type:

dict, read-only

core_attrs

The “core attributes”, represented as a dict object. For each dict key key in core_attrs, validation_and_conversion_funcs[key](core_attrs) is expected to not raise an exception.

Type:

dict, read-only

Methods

de_pre_serialize	Construct an instance from a serializable representation.
dump	Serialize instance and save the result in a JSON file.
dumps	Serialize instance.
get_core_attrs	Return the core attributes.
load	Construct an instance from a serialized representation that is stored in a JSON file.
loads	Construct an instance from a serialized representation.
pre_serialize	Pre-serialize instance.

Attributes

core_attrs
de_pre_serialization_funcs
pre_serialization_funcs
validation_and_conversion_funcs

classmethod de_pre_serialize(validation_and_conversion_funcs={}, pre_serialization_funcs={}, de_pre_serialization_funcs={}, serializable_rep={}, skip_validation_and_conversion=False)

Construct an instance from a serializable representation.

We define pre-serialization as the process of converting an object into a form that can be subsequently serialized into a JSON format. We refer to objects resulting from pre-serialization as serializable objects.

We define de-pre-serialization as the process of converting a serializable object into an instance of the type fancytypes.PreSerializable or a subclass thereof, i.e. de-pre-serialization is the reverse process of pre-serialization.

Parameters:

• validation_and_conversion_funcs (dict, optional) – Same as the constructor parameter of the same name.

• pre_serialization_funcs (dict, optional) – Same as the constructor parameter of the same name.

• de_pre_serialization_funcs (dict, optional) – Same as the constructor parameter of the same name.

• serializable_rep (dict, optional) –

  A dict object that has a key set that is any subset of that of validation_and_conversion_funcs.

  The items of serializable_rep are expected to be objects that would lead to de_pre_serialization_funcs[key](serializable_rep[key]) not raising an exception for each dict key key in serializable_rep.

  Let core_attrs_candidate be a dict object that has the same keys as serializable_rep, where for each dict key key in serializable_rep, core_attrs_candidate[key] is set to de_pre_serialization_funcs[key](serializable_rep[key])``.

  The items of serializable_rep are also expected to be set to objects that would lead to validation_and_conversion_funcs[key](core_attrs_candidate) not raising an exception for each dict key key in serializable_rep.

• skip_validation_and_conversion (bool, optional) –

  Let core_attrs denote the attribute fancytypes.PreSerializable.core_attrs, which is a dict object.

  If skip_validation_and_conversion is set to False, then for each key key in serializable_rep, core_attrs[key] is set to validation_and_conversion_funcs[key] (core_attrs_candidate), with core_attrs_candidate_ being defined in the above description of serializable_rep.

  Otherwise, if skip_validation_and_conversion is set to True, then core_attrs is set to core_attrs_candidate. This option is desired primarily when the user wants to avoid potentially expensive copies and/or conversions of the dict values of core_attrs_candidate, as it is guaranteed that no copies or conversions are made in this case.

Returns:

instance_of_current_cls – An instance constructed from the serializable representation serializable_rep.

Return type:

Current class

dump(filename='serialized_rep_of_fancytype.json', overwrite=False)

Serialize instance and save the result in a JSON file.

Parameters:

• filename (str, optional) – The relative or absolute path to the JSON file in which to store the serialized representation of an instance.

• overwrite (bool, optional) – If overwrite is set to False and a file exists at the path filename, then the serialized instance is not written to that file and an exception is raised. Otherwise, the serialized instance will be written to that file barring no other issues occur.

dumps()

Serialize instance.

Returns:

serialized_rep – A serialized representation of an instance.

Return type:

dict

get_core_attrs(deep_copy=True)

Return the core attributes.

Parameters:

deep_copy (bool, optional) – If deep_copy is set to True, then a deep copy of the original dict representation of the core attributes are returned. Otherwise, a reference to the dict representation is returned.

Returns:

core_attrs – A dict representation of the core attributes: each dict key is a str representing the name of a core attribute, and the corresponding dict value is the object to which said core attribute is set.

Return type:

dict

classmethod load(validation_and_conversion_funcs={}, pre_serialization_funcs={}, de_pre_serialization_funcs={}, filename='serialized_rep_of_fancytype.json', skip_validation_and_conversion=False)

Construct an instance from a serialized representation that is stored in a JSON file.

Users can save serialized representations to JSON files using the method fancytypes.PreSerializable.dump().

Parameters:

• validation_and_conversion_funcs (dict, optional) – Same as the constructor parameter of the same name.

• pre_serialization_funcs (dict, optional) – Same as the constructor parameter of the same name.

• de_pre_serialization_funcs (dict, optional) – Same as the constructor parameter of the same name.

• filename (str, optional) –

  The relative or absolute path to the JSON file that is storing the serialized representation of an instance.

  filename is expected to be such that json.load(open(filename, "r")) does not raise an exception.

  Let serializable_rep=json.load(open(filename, "r")).

  filename is also expected to be such that de_pre_serialization_funcs[key](serializable_rep[key]) does not raise an exception for each dict key key in serializable_rep.

  Let core_attrs_candidate be a dict object that has the same keys as serializable_rep, where for each dict key key in serializable_rep, core_attrs_candidate[key] is set to de_pre_serialization_funcs[key](serializable_rep[key])``.

  filename is also expected to be such that validation_and_conversion_funcs[key](core_attrs_candidate) does not raising an exception for each dict key key in serializable_rep.

• skip_validation_and_conversion (bool, optional) –

  Let core_attrs denote the attribute fancytypes.PreSerializable.core_attrs, which is a dict object.

  Let core_attrs_candidate be as defined in the above description of filename.

  If skip_validation_and_conversion is set to False, then for each key key in core_attrs_candidate, core_attrs[key] is set to validation_and_conversion_funcs[key] (core_attrs_candidate).

  Otherwise, if skip_validation_and_conversion is set to True, then core_attrs is set to core_attrs_candidate. This option is desired primarily when the user wants to avoid potentially expensive copies and/or conversions of the dict values of core_attrs_candidate, as it is guaranteed that no copies or conversions are made in this case.

Returns:

instance_of_current_cls – An instance constructed from the serialized representation stored in the JSON file.

Return type:

Current class

classmethod loads(validation_and_conversion_funcs={}, pre_serialization_funcs={}, de_pre_serialization_funcs={}, serialized_rep='{}', skip_validation_and_conversion=False)

Construct an instance from a serialized representation.

Users can generate serialized representations using the method fancytypes.PreSerializable.dumps().

Parameters:

• validation_and_conversion_funcs (dict, optional) – Same as the constructor parameter of the same name.

• pre_serialization_funcs (dict, optional) – Same as the constructor parameter of the same name.

• de_pre_serialization_funcs (dict, optional) – Same as the constructor parameter of the same name.

• serialized_rep (str | bytes | bytearray, optional) –

  The serialized representation.

  serialized_rep is expected to be such that json.loads(serialized_rep) does not raise an exception.

  Let serializable_rep=json.loads(serialized_rep).

  serialized_rep is also expected to be such that de_pre_serialization_funcs[key](serializable_rep[key]) does not raise an exception for each dict key key in serializable_rep.

  Let core_attrs_candidate be a dict object that has the same keys as serializable_rep, where for each dict key key in serializable_rep, core_attrs_candidate[key] is set to de_pre_serialization_funcs[key](serializable_rep[key])``.

  serialized_rep is also expected to be such that validation_and_conversion_funcs[key](core_attrs_candidate) does not raising an exception for each dict key key in serializable_rep.

• skip_validation_and_conversion (bool, optional) –

  Let core_attrs denote the attribute fancytypes.PreSerializable.core_attrs, which is a dict object.

  Let core_attrs_candidate be as defined in the above description of serialized_rep.

  If skip_validation_and_conversion is set to False, then for each key key in core_attrs_candidate, core_attrs[key] is set to validation_and_conversion_funcs[key] (core_attrs_candidate).

  Otherwise, if skip_validation_and_conversion is set to True, then core_attrs is set to core_attrs_candidate. This option is desired primarily when the user wants to avoid potentially expensive copies and/or conversions of the dict values of core_attrs_candidate, as it is guaranteed that no copies or conversions are made in this case.

Returns:

instance_of_current_cls – An instance constructed from the serialized representation.

Return type:

Current class

pre_serialize()

Pre-serialize instance.

We define pre-serialization as the process of converting an object into a form that can be subsequently serialized into a JSON format. We refer to objects resulting from pre-serialization as serializable objects.

We define de-pre-serialization as the process of converting a serializable object into an instance of the type fancytypes.PreSerializable or a subclass thereof, i.e. de-pre-serialization is the reverse process of pre-serialization.

Returns:

serializable_rep – A serializable representation of an instance.

Return type:

dict