codekingpro/portable-devtools

1# Copyright 2016 Google LLC2#3# Licensed under the Apache License, Version 2.0 (the "License");4# you may not use this file except in compliance with the License.5# You may obtain a copy of the License at6#7#      http://www.apache.org/licenses/LICENSE-2.08#9# Unless required by applicable law or agreed to in writing, software10# distributed under the License is distributed on an "AS IS" BASIS,11# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.12# See the License for the specific language governing permissions and13# limitations under the License.14 15"""Base classes for cryptographic signers and verifiers."""16 17import abc18import io19import json20 21from google.auth import exceptions22 23_JSON_FILE_PRIVATE_KEY = "private_key"24_JSON_FILE_PRIVATE_KEY_ID = "private_key_id"25 26 27class Verifier(metaclass=abc.ABCMeta):28    """Abstract base class for crytographic signature verifiers."""29 30    @abc.abstractmethod31    def verify(self, message, signature):32        """Verifies a message against a cryptographic signature.33 34        Args:35            message (Union[str, bytes]): The message to verify.36            signature (Union[str, bytes]): The cryptography signature to check.37 38        Returns:39            bool: True if message was signed by the private key associated40            with the public key that this object was constructed with.41        """42        # pylint: disable=missing-raises-doc,redundant-returns-doc43        # (pylint doesn't recognize that this is abstract)44        raise NotImplementedError("Verify must be implemented")45 46 47class Signer(metaclass=abc.ABCMeta):48    """Abstract base class for cryptographic signers."""49 50    @abc.abstractproperty51    def key_id(self):52        """Optional[str]: The key ID used to identify this private key."""53        raise NotImplementedError("Key id must be implemented")54 55    @abc.abstractmethod56    def sign(self, message):57        """Signs a message.58 59        Args:60            message (Union[str, bytes]): The message to be signed.61 62        Returns:63            bytes: The signature of the message.64        """65        # pylint: disable=missing-raises-doc,redundant-returns-doc66        # (pylint doesn't recognize that this is abstract)67        raise NotImplementedError("Sign must be implemented")68 69 70class FromServiceAccountMixin(metaclass=abc.ABCMeta):71    """Mix-in to enable factory constructors for a Signer."""72 73    @abc.abstractmethod74    def from_string(cls, key, key_id=None):75        """Construct an Signer instance from a private key string.76 77        Args:78            key (str): Private key as a string.79            key_id (str): An optional key id used to identify the private key.80 81        Returns:82            google.auth.crypt.Signer: The constructed signer.83 84        Raises:85            ValueError: If the key cannot be parsed.86        """87        raise NotImplementedError("from_string must be implemented")88 89    @classmethod90    def from_service_account_info(cls, info):91        """Creates a Signer instance instance from a dictionary containing92        service account info in Google format.93 94        Args:95            info (Mapping[str, str]): The service account info in Google96                format.97 98        Returns:99            google.auth.crypt.Signer: The constructed signer.100 101        Raises:102            ValueError: If the info is not in the expected format.103        """104        if _JSON_FILE_PRIVATE_KEY not in info:105            raise exceptions.MalformedError(106                "The private_key field was not found in the service account " "info."107            )108 109        return cls.from_string(110            info[_JSON_FILE_PRIVATE_KEY], info.get(_JSON_FILE_PRIVATE_KEY_ID)111        )112 113    @classmethod114    def from_service_account_file(cls, filename):115        """Creates a Signer instance from a service account .json file116        in Google format.117 118        Args:119            filename (str): The path to the service account .json file.120 121        Returns:122            google.auth.crypt.Signer: The constructed signer.123        """124        with io.open(filename, "r", encoding="utf-8") as json_file:125            data = json.load(json_file)126 127        return cls.from_service_account_info(data)128