Util File

exception dffml.util.file.HashValidationError(path, value, expected)

Raised when hash of file is not what was expected

exception dffml.util.file.NoHashToUseForValidationSuppliedError

A hash to validate file contents against was not supplied.

dffml.util.file.find_replace_with_hash_validation(original_path: Path, replaced_path: Path, find_regex: str, replace: str, *, expected_sha384_hash: Optional[str] = None) → Path

Given an original file path, a file path to write out to, a regex to supply to re.sub(), a string to replace, and a hash to validate the replaced contents with.

Read the contents of the original file, run a regex find and replace, write the contents out to replaced_path. Validate the contents is as expected.

Examples

>>> import pathlib
>>> from dffml import find_replace_with_hash_validation
>>>
>>> original_path = pathlib.Path("file.txt")
>>> original_path.write_text("Hello World\n")
12
>>>
>>> replaced_path = find_replace_with_hash_validation(
...     original_path,
...     original_path.parent / "subdir" / "new_file.txt",
...     r"World",
...     "FeedFace",
...     expected_sha384_hash="00d7bdbf0b24d37463bd9d2107926c3fa870537c009cd64dde72c3578160d9e04f63bf487631a2e2e7610f9654cf0f78",
... )
>>>
>>> print(replaced_path.read_bytes())
b'Hello FeedFace\n'

dffml.util.file.validate_file_hash(filepath: Union[str, Path], *, expected_sha384_hash: Optional[str] = None, error: bool = True, chunk_size: int = 8192)

Read the contents of a file, hash the contents, and compare that hash to the one given.

Examples

Write out file.txt with the contents of b”Hello Worldn”. Then check it to see if the SHA 384 hash of the contents matches the SHA 384 hash for b”Hello FeedFacen”.

>>> import pathlib
>>> import hashlib
>>> from dffml import validate_file_hash
>>>
>>> correct_contents = b"Hello FeedFace\n"
>>> expected_sha384_hash = hashlib.sha384(correct_contents).hexdigest()
>>>
>>> original_path = pathlib.Path("file.txt")
>>> original_path.write_text("Hello World\n")
12
>>>
>>> validate_file_hash(
...     original_path,
...     expected_sha384_hash=expected_sha384_hash,
... )
Traceback (most recent call last):
    ...
dffml.util.file.HashValidationError: file.txt hash was acbfd470c22c0d95a1d10a087dc31988b9f7bfeb13be70b876a73558be664e5858d11f9459923e6e5fd838cb5708b969, should be 00d7bdbf0b24d37463bd9d2107926c3fa870537c009cd64dde72c3578160d9e04f63bf487631a2e2e7610f9654cf0f78
>>>
>>> validate_file_hash(
...     original_path,
...     expected_sha384_hash=expected_sha384_hash,
...     error=False,
... )
False
>>>
>>> # Write the correct contents to the file so validation passes
>>> original_path.write_bytes(correct_contents)
15
>>> validate_file_hash(
...     original_path,
...     expected_sha384_hash=expected_sha384_hash,
... )
True