marshal — Internal Python object serialization¶
This module contains functions that can read and write Python values in a binary format. The format is specific to Python, but independent of machine architecture issues (e.g., you can write a Python value to a file on a PC, transport the file to a Mac, and read it back there). Details of the format are undocumented on purpose; it may change between Python versions (although it rarely does). [1]
This is not a general «persistence» module. For general persistence and
transfer of Python objects through RPC calls, see the modules pickle and
shelve. The marshal module exists mainly to support reading and
writing the «pseudo-compiled» code for Python modules of .pyc files.
Therefore, the Python maintainers reserve the right to modify the marshal format
in backward incompatible ways should the need arise.
The format of code objects is not compatible between Python versions,
even if the version of the format is the same.
De-serializing a code object in the incorrect Python version has undefined behavior.
If you’re serializing and
de-serializing Python objects, use the pickle module instead – the
performance is comparable, version independence is guaranteed, and pickle
supports a substantially wider range of objects than marshal.
Advertencia
El módulo marshal no está destinado a ser seguro contra datos erróneos o construidos maliciosamente. Nunca deserializar con marshal los datos recibidos de una fuente no confiable o no autenticada.
Not all Python object types are supported; in general, only objects whose value
is independent from a particular invocation of Python can be written and read by
this module. The following types are supported: booleans, integers, floating-point
numbers, complex numbers, strings, bytes, bytearrays, tuples, lists, sets,
frozensets, dictionaries, and code objects (if allow_code is true),
where it should be understood that
tuples, lists, sets, frozensets and dictionaries are only supported as long as
the values contained therein are themselves supported. The
singletons None, Ellipsis and StopIteration can also be
marshalled and unmarshalled.
For format version lower than 3, recursive lists, sets and dictionaries cannot
be written (see below).
Hay funciones que leen/escriben archivos, así como funciones que operan en objetos similares a bytes.
El módulo define estas funciones:
- marshal.dump(value, file, version=version, /, *, allow_code=True)¶
Escribe el valor en el archivo abierto. El valor debe ser un tipo admitido. El archivo debe ser un archivo binary file en el que se pueda escribir.
If the value has (or contains an object that has) an unsupported type, a
ValueErrorexception is raised — but garbage data will also be written to the file. The object will not be properly read back byload(). Code objects are only supported if allow_code is true.El argumento version indica el formato de datos que
dumpdebe usar (véase más adelante).Lanza un evento de auditoría
marshal.dumpscon argumentosvalue,version.Distinto en la versión 3.13: Added the allow_code parameter.
- marshal.load(file, /, *, allow_code=True)¶
Read one value from the open file and return it. If no valid value is read (e.g. because the data has a different Python version’s incompatible marshal format), raise
EOFError,ValueErrororTypeError. Code objects are only supported if allow_code is true. The file must be a readable binary file.Lanza un evento de auditoría
marshal.loadsin argumentos.Nota
Si un objeto que contiene un tipo no admitido se calcula con
dump(),load()sustituiráNonepor el tipo «unmarshallable».Distinto en la versión 3.10: Esta llamada solía lanzar un evento de auditoría
code.__new__para cada objeto código. Ahora lanza un único eventomarshal.loadpara toda la operación de carga.Distinto en la versión 3.13: Added the allow_code parameter.
- marshal.dumps(value, version=version, /, *, allow_code=True)¶
Return the bytes object that would be written to a file by
dump(value, file). The value must be a supported type. Raise aValueErrorexception if value has (or contains an object that has) an unsupported type. Code objects are only supported if allow_code is true.El argumento version indica el formato de datos que
dumpsdebe usar (véase más adelante).Lanza un evento de auditoría
marshal.dumpscon argumentosvalue,version.Distinto en la versión 3.13: Added the allow_code parameter.
- marshal.loads(bytes, /, *, allow_code=True)¶
Convert the bytes-like object to a value. If no valid value is found, raise
EOFError,ValueErrororTypeError. Code objects are only supported if allow_code is true. Extra bytes in the input are ignored.Lanza un evento de auditoría
marshal.loadscon argumentobytes.Distinto en la versión 3.10: Esta llamada solía lanzar un evento de auditoría
code.__new__para cada objeto código. Ahora lanza un único eventomarshal.loadspara toda la operación de carga.Distinto en la versión 3.13: Added the allow_code parameter.
Además, se definen las siguientes constantes:
- marshal.version¶
Indicates the format that the module uses. Version 0 is the historical format, version 1 shares interned strings and version 2 uses a binary format for floating-point numbers. Version 3 adds support for object instancing and recursion. The current version is 4.
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