ScopedTemporaryFile.py

import errno
import tempfile
import os


class ScopedTemporaryFile(object):
    """ Temp file to use in a with statement.

    with ScopedTemporaryFile() as f:
        ... do stuff with f ...

    f is a file-like object that behaves like one would expect from a
    NamedTemporaryFile. It can be closed and opened again.
    File is automatically deleted once the block finishes.
    """
    def __init__(self, mode='w+b'):
        self._file = tempfile.NamedTemporaryFile(mode, delete=False)
        self._name = self._file.name

    def __enter__(self):
        return self

    def __exit__(self, type, value, traceback):
        self._file.close()
        try:
            os.unlink(self._name)
        except OSError as e:
            # file doesn't exist: already removed?
            if e.errno != errno.ENOENT:
                raise

    def __getattr__(self, item):
        return getattr(self._file, item)

    def open(self, mode='r'):
        """ Open the file again """
        self._file = open(self._name, mode)


def _main():
    with ScopedTemporaryFile() as f:
        fname = f.name
        print("{fn} exists? {exists}".format(
            fn=fname,
            exists=os.path.exists(fname)
        ))
        f.close()
        print("{fn} exists? {exists} after close".format(
            fn=fname,
            exists=os.path.exists(fname)
        ))

    print("{fn} exists? {exists} after block".format(
        fn=fname,
        exists=os.path.exists(fname)
    ))


if __name__ == "__main__":
    _main()