Determining Whether a Directory is Writeable

Question

What would be the best way in Python to determine whether a directory is writeable for the user executing the script? Since this will likely involve using the os module I sh

Answer 1

My solution using the tempfile module:

import tempfile
import errno

def isWritable(path):
    try:
        testfile = tempfile.TemporaryFile(dir = path)
        testfile.close()
    except OSError as e:
        if e.errno == errno.EACCES:  # 13
            return False
        e.filename = path
        raise
    return True

Update: After testing the code again on Windows I see that there is indeed an issue when using tempfile there, see issue22107: tempfile module misinterprets access denied error on Windows. In the case of a non-writable directory, the code hangs for several seconds and finally throws an IOError: [Errno 17] No usable temporary file name found. Maybe this is what user2171842 was observing? Unfortunately the issue is not resolved for now so to handle this, the error needs to be caught as well:

    except (OSError, IOError) as e:
        if e.errno == errno.EACCES or e.errno == errno.EEXIST:  # 13, 17

The delay is of course still present in these cases then.