metadata.py 文件源码

def json_ready_header(header):
    # type: (MessageHeader) -> Dict[str, Any]
    """Create a JSON-serializable representation of a :class:`aws_encryption_sdk.structures.MessageHeader`.

    http://docs.aws.amazon.com/encryption-sdk/latest/developer-guide/message-format.html#header-structure

    :param header: header for which to create a JSON-serializable representation
    :type header: aws_encryption_sdk.structures.MessageHeader
    :rtype: dict
    """
    dict_header = attr.asdict(header)

    del dict_header['content_aad_length']
    dict_header['version'] = str(float(dict_header['version'].value))
    dict_header['algorithm'] = dict_header['algorithm'].name

    for key, value in dict_header.items():
        if isinstance(value, Enum):
            dict_header[key] = value.value

    dict_header['message_id'] = unicode_b64_encode(dict_header['message_id'])

    dict_header['encrypted_data_keys'] = sorted(
        list(dict_header['encrypted_data_keys']),
        key=lambda x: six.b(x['key_provider']['provider_id']) + x['key_provider']['key_info']
    )
    for data_key in dict_header['encrypted_data_keys']:
        data_key['key_provider']['provider_id'] = unicode_b64_encode(six.b(data_key['key_provider']['provider_id']))
        data_key['key_provider']['key_info'] = unicode_b64_encode(data_key['key_provider']['key_info'])
        data_key['encrypted_data_key'] = unicode_b64_encode(data_key['encrypted_data_key'])

    return dict_header