builders.py

# This file is part of CycloneDX Python Library
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
# SPDX-License-Identifier: Apache-2.0
# Copyright (c) OWASP Foundation. All Rights Reserved.

"""Component related builders"""


from hashlib import sha1
from os.path import exists
from typing import Optional

from ...model import HashAlgorithm, HashType
from ...model.component import Component, ComponentType


class ComponentBuilder:

    def make_for_file(self, absolute_file_path: str, *,
                      name: Optional[str]) -> Component:
        """
        Helper method to create a :class:`cyclonedx.model.component.Component`
        that represents the provided local file as a Component.

        Args:
            absolute_file_path:
                Absolute path to the file you wish to represent
            name:
                Optionally, if supplied this is the name that will be used for the component.
                Defaults to arg ``absolute_file_path``.

        Returns:
            `Component` representing the supplied file
        """
        if not exists(absolute_file_path):
            raise FileExistsError(f'Supplied file path {absolute_file_path!r} does not exist')

        return Component(
            type=ComponentType.FILE,
            name=name or absolute_file_path,
            hashes=[
                HashType(alg=HashAlgorithm.SHA_1, content=self._file_sha1sum(absolute_file_path))
            ]
        )

    @staticmethod
    def _file_sha1sum(filename: str) -> str:
        """
        Generate a SHA1 hash of the provided file.

        Args:
            filename:
                Absolute path to file to hash as `str`

        Returns:
            SHA-1 hash
        """
        h = sha1()  # nosec B303, B324
        with open(filename, 'rb') as f:
            for byte_block in iter(lambda: f.read(4096), b''):
                h.update(byte_block)
        return h.hexdigest()