safer 0.9.6

Try to import all modules below a given root

✏️safer ✏️

Safely write or print to a file, leaving it unchanged if there’s an exception.

Works on Python versions 2.7 through 3.8 and likely beyond.

Writes are performed on a temporary file, which is only copied over the original file after the context completes successfully. Note that this temporarily uses as much disk space as the old file and the new file put together.

EXAMPLES

safer.open

import safer

with safer.open(filename, 'w') as fp:
    for line in source():
       fp.write('this and that\n')
       fp.write('two-lines!')

    if CHANGED_MY_MIND:
        raise ValueError
        # Contents of `filename` will be unchanged

safer.printer

with safer.printer(filename) as print:
    print('this', 'and', 'that')
    print('two', 'lines', sep='-', end='!')

    if CHANGED_MY_MIND:
        raise ValueError
        # Contents of ``filename`` will be unchanged

API call documentation

safer.open(file, mode='r', create_parents=False, delete_failures=True, suffix='.tmp')

A context that yields a stream like built-in open() would, and undoes any changes to the file if there’s an exception.

Arguments:

file:

Path to the file to be opened

mode:

Mode string passed to built-in open

create_parents:

If True, all parent directories are automatically created

delete_failures:

Are partial files deleted if the context terminates with an exception?

suffix:

File suffix to use for temporary files

safer.printer(file, mode='w', create_parents=False, delete_failures=True, suffix='.tmp')

A context that yields a print function that prints to the file, but which undoes any changes to the file if there’s an exception.

Arguments:

file:

Path to the file to be opened

mode:

Mode string passed to built-in open

create_parents:

If True, all parent directories are automatically created

delete_failures:

Are partial files deleted if the context terminates with an exception?

suffix:

File suffix to use for temporary files