mirror of
https://github.com/theupdateframework/python-tuf
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83 lines
3.1 KiB
Python
83 lines
3.1 KiB
Python
# Copyright New York University and the TUF contributors
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# SPDX-License-Identifier: MIT OR Apache-2.0
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"""TUF role metadata JSON serialization and deserialization.
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This module provides concrete implementations to serialize and deserialize TUF
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role metadata to and from the JSON wireline format for transportation, and
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to serialize the 'signed' part of TUF role metadata to the OLPC Canonical JSON
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format for signature generation and verification.
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"""
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import json
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import six
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from securesystemslib.formats import encode_canonical
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# pylint: disable=cyclic-import
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# ... to allow de/serializing Metadata and Signed objects here, while also
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# creating default de/serializers there (see metadata local scope imports).
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# NOTE: A less desirable alternative would be to add more abstraction layers.
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from tuf.api.metadata import Metadata, Signed
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from tuf.api.serialization import (MetadataSerializer,
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MetadataDeserializer,
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SignedSerializer,
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SerializationError,
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DeserializationError)
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class JSONDeserializer(MetadataDeserializer):
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"""Provides JSON-to-Metadata deserialize method. """
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def deserialize(self, raw_data: bytes) -> Metadata:
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"""Deserialize utf-8 encoded JSON bytes into Metadata object. """
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try:
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json_dict = json.loads(raw_data.decode("utf-8"))
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metadata_obj = Metadata.from_dict(json_dict)
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except Exception as e: # pylint: disable=broad-except
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six.raise_from(DeserializationError, e)
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return metadata_obj
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class JSONSerializer(MetadataSerializer):
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"""A Metadata-to-JSON serialize method.
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Attributes:
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compact: A boolean indicating if the JSON bytes generated in
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'serialize' should be compact by excluding whitespace.
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"""
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def __init__(self, compact: bool = False) -> None:
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self.compact = compact
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def serialize(self, metadata_obj: Metadata) -> bytes:
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"""Serialize Metadata object into utf-8 encoded JSON bytes. """
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try:
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indent = (None if self.compact else 1)
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separators = ((',', ':') if self.compact else (',', ': '))
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json_bytes = json.dumps(metadata_obj.to_dict(),
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indent=indent,
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separators=separators,
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sort_keys=True).encode("utf-8")
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except Exception as e: # pylint: disable=broad-except
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six.raise_from(SerializationError, e)
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return json_bytes
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class CanonicalJSONSerializer(SignedSerializer):
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"""A Signed-to-Canonical JSON 'serialize' method. """
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def serialize(self, signed_obj: Signed) -> bytes:
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"""Serialize Signed object into utf-8 encoded Canonical JSON bytes. """
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try:
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signed_dict = signed_obj.to_dict()
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canonical_bytes = encode_canonical(signed_dict).encode("utf-8")
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except Exception as e: # pylint: disable=broad-except
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six.raise_from(SerializationError, e)
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return canonical_bytes
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