python-tuf/tuf/api/serialization/__init__.py

# Copyright New York University and the TUF contributors
# SPDX-License-Identifier: MIT OR Apache-2.0

"""TUF role metadata de/serialization.

This sub-package provides abstract base classes and concrete implementations to
serialize and deserialize TUF role metadata and metadata parts.

Any custom de/serialization implementations should inherit from the abstract
base classes defined in this __init__.py module.

- Metadata de/serializers are used to convert to and from wireline formats.
- Signed serializers are used to canonicalize data for cryptographic signatures
  generation and verification.

"""
import abc


# TODO: Should these be in tuf.exceptions or inherit from tuf.exceptions.Error?
class SerializationError(Exception):
    """Error during serialization."""


class DeserializationError(Exception):
    """Error during deserialization."""


class MetadataDeserializer(metaclass=abc.ABCMeta):
    """Abstract base class for deserialization of Metadata objects."""

    @abc.abstractmethod
    def deserialize(self, raw_data: bytes) -> "Metadata":
        """Deserialize passed bytes to Metadata object."""
        raise NotImplementedError


class MetadataSerializer(metaclass=abc.ABCMeta):
    """Abstract base class for serialization of Metadata objects."""

    @abc.abstractmethod
    def serialize(self, metadata_obj: "Metadata") -> bytes:
        """Serialize passed Metadata object to bytes."""
        raise NotImplementedError


class SignedSerializer(metaclass=abc.ABCMeta):
    """Abstract base class for serialization of Signed objects."""

    @abc.abstractmethod
    def serialize(self, signed_obj: "Signed") -> bytes:
        """Serialize passed Signed object to bytes."""
        raise NotImplementedError