base.rst

fs.base

This module contains the basic FS interface and a number of other essential interfaces.

fs.base.FS

All Filesystem objects inherit from this class.

.. autoclass:: fs.base.FS
    :members:

fs.base.SubFS

A SubFS is an FS implementation that represents a directory on another Filesystem. When you use the :meth:`~fs.base.FS.opendir` method it will return a SubFS instance. You should not need to instantiate a SubFS directly.

For example:

from fs.osfs import OSFS
home_fs = OSFS('foo')
bar_fs = home_fs.opendir('bar')

fs.base.NullFile

A NullFile is a file-like object with no functionality. It is used in situations where a file-like object is required but the caller doesn't have any data to read or write.

The :meth:`~fs.base.FS.safeopen` method returns a NullFile instance, which can reduce error-handling code.

For example, the following code may be written to append some text to a log file:

logfile = None
try:
    logfile = myfs.open('log.txt', 'a')
    logfile.writeline('operation successful!')
finally:
    if logfile is not None:
        logfile.close()

This could be re-written using the safeopen method:

myfs.safeopen('log.txt', 'a').writeline('operation successful!')

If the file doesn't exist then the call to writeline will be a null-operation (i.e. not do anything).