This module provides generic, low- and high-level interfaces for
creating temporary files and directories. All of the interfaces
provided by this module can be used without fear of race conditions
except for 'mktemp'. 'mktemp' is subject to race conditions and
should not be used; it is provided for backward compatibility only.
This module also provides some data items to the user:
TMP_MAX - maximum number of names that will be tried before
template - the default prefix for all temporary names.
You may change this to control the default prefix.
tempdir - If this is set to a string before the first use of
any routine from this module, it will be considered as
another candidate location to store temporary files.
"NamedTemporaryFile", "TemporaryFile", # high level safe interfaces
"mkstemp", "mkdtemp", # low level safe interfaces
"mktemp", # deprecated unsafe interface
"TMP_MAX", "gettempprefix", # constants
from random import Random as _Random
from cStringIO import StringIO as _StringIO
from StringIO import StringIO as _StringIO
flags = _fcntl.fcntl(fd, _fcntl.F_GETFD, 0)
# flags read successfully, modify
flags |= _fcntl.FD_CLOEXEC
_fcntl.fcntl(fd, _fcntl.F_SETFD, flags)
import dummy_thread as _thread
_allocate_lock = _thread.allocate_lock
_text_openflags = _os.O_RDWR | _os.O_CREAT | _os.O_EXCL
if hasattr(_os, 'O_NOINHERIT'):
_text_openflags |= _os.O_NOINHERIT
if hasattr(_os, 'O_NOFOLLOW'):
_text_openflags |= _os.O_NOFOLLOW
_bin_openflags = _text_openflags
if hasattr(_os, 'O_BINARY'):
_bin_openflags |= _os.O_BINARY
if hasattr(_os, 'TMP_MAX'):
_once_lock = _allocate_lock()
if hasattr(_os, "lstat"):
elif hasattr(_os, "stat"):
# Fallback. All we need is something that raises os.error if the
class _RandomNameSequence:
"""An instance of _RandomNameSequence generates an endless
sequence of unpredictable strings which can safely be incorporated
into file names. Each string is six characters long. Multiple
threads can safely use the same instance at the same time.
_RandomNameSequence is an iterator."""
characters = ("abcdefghijklmnopqrstuvwxyz" +
"ABCDEFGHIJKLMNOPQRSTUVWXYZ" +
self.mutex = _allocate_lock()
self.normcase = _os.path.normcase
if cur_pid != getattr(self, '_rng_pid', None):
letters = [choose(c) for dummy in "123456"]
return self.normcase(''.join(letters))
def _candidate_tempdir_list():
"""Generate a list of candidate temporary directories which
_get_default_tempdir will try."""
# First, try the environment.
for envname in 'TMPDIR', 'TEMP', 'TMP':
dirname = _os.getenv(envname)
if dirname: dirlist.append(dirname)
# Failing that, try OS-specific locations.
dirname = _os.getenv('Wimp$ScrapDir')
if dirname: dirlist.append(dirname)
dirlist.extend([ r'c:\temp', r'c:\tmp', r'\temp', r'\tmp' ])
dirlist.extend([ '/tmp', '/var/tmp', '/usr/tmp' ])
# As a last resort, the current directory.
dirlist.append(_os.getcwd())
except (AttributeError, _os.error):
dirlist.append(_os.curdir)
def _get_default_tempdir():
"""Calculate the default directory to use for temporary files.
This routine should be called exactly once.
We determine whether or not a candidate temp dir is usable by
trying to create and write to a file in that directory. If this
is successful, the test file is deleted. To prevent denial of
service, the name of the test file must be randomized."""
namer = _RandomNameSequence()
dirlist = _candidate_tempdir_list()
dir = _os.path.normcase(_os.path.abspath(dir))
# Try only a few names per directory.
filename = _os.path.join(dir, name)
fd = _os.open(filename, flags, 0o600)
with _io.open(fd, 'wb', closefd=False) as fp:
except (OSError, IOError) as e:
if e.args[0] == _errno.EEXIST:
if (_os.name == 'nt' and e.args[0] == _errno.EACCES and
_os.path.isdir(dir) and _os.access(dir, _os.W_OK)):
# On windows, when a directory with the chosen name already
# exists, EACCES error code is returned instead of EEXIST.
break # no point trying more names in this directory
raise IOError, (_errno.ENOENT,
("No usable temporary directory found in %s" % dirlist))
def _get_candidate_names():
"""Common setup sequence for all user-callable interfaces."""
if _name_sequence is None:
if _name_sequence is None:
_name_sequence = _RandomNameSequence()
def _mkstemp_inner(dir, pre, suf, flags):
"""Code common to mkstemp, TemporaryFile, and NamedTemporaryFile."""
names = _get_candidate_names()
for seq in xrange(TMP_MAX):
file = _os.path.join(dir, pre + name + suf)
fd = _os.open(file, flags, 0600)
return (fd, _os.path.abspath(file))
if e.errno == _errno.EEXIST:
if (_os.name == 'nt' and e.errno == _errno.EACCES and
_os.path.isdir(dir) and _os.access(dir, _os.W_OK)):
# On windows, when a directory with the chosen name already
# exists, EACCES error code is returned instead of EEXIST.
raise IOError, (_errno.EEXIST, "No usable temporary file name found")
# User visible interfaces.
"""Accessor for tempdir.template."""
"""Accessor for tempfile.tempdir."""
tempdir = _get_default_tempdir()
def mkstemp(suffix="", prefix=template, dir=None, text=False):
"""User-callable function to create and return a unique temporary
file. The return value is a pair (fd, name) where fd is the
file descriptor returned by os.open, and name is the filename.
If 'suffix' is specified, the file name will end with that suffix,
otherwise there will be no suffix.
If 'prefix' is specified, the file name will begin with that prefix,
otherwise a default prefix is used.
If 'dir' is specified, the file will be created in that directory,
otherwise a default directory is used.
If 'text' is specified and true, the file is opened in text
mode. Else (the default) the file is opened in binary mode. On
some operating systems, this makes no difference.
The file is readable and writable only by the creating user ID.
If the operating system uses permission bits to indicate whether a
file is executable, the file is executable by no one. The file
descriptor is not inherited by children of this process.
Caller is responsible for deleting the file when done with it.
return _mkstemp_inner(dir, prefix, suffix, flags)
def mkdtemp(suffix="", prefix=template, dir=None):
"""User-callable function to create and return a unique temporary
directory. The return value is the pathname of the directory.
Arguments are as for mkstemp, except that the 'text' argument is
The directory is readable, writable, and searchable only by the
Caller is responsible for deleting the directory when done with it.
names = _get_candidate_names()
for seq in xrange(TMP_MAX):
file = _os.path.join(dir, prefix + name + suffix)
if e.errno == _errno.EEXIST:
if (_os.name == 'nt' and e.errno == _errno.EACCES and
_os.path.isdir(dir) and _os.access(dir, _os.W_OK)):
# On windows, when a directory with the chosen name already
# exists, EACCES error code is returned instead of EEXIST.
raise IOError, (_errno.EEXIST, "No usable temporary directory name found")
def mktemp(suffix="", prefix=template, dir=None):
"""User-callable function to return a unique temporary file name. The
Arguments are as for mkstemp, except that the 'text' argument is
This function is unsafe and should not be used. The file name
refers to a file that did not exist at some point, but by the time
you get around to creating it, someone else may have beaten you to
## from warnings import warn as _warn
## _warn("mktemp is a potential security risk to your program",
## RuntimeWarning, stacklevel=2)
names = _get_candidate_names()
for seq in xrange(TMP_MAX):
file = _os.path.join(dir, prefix + name + suffix)
raise IOError, (_errno.EEXIST, "No usable temporary filename found")
class _TemporaryFileWrapper:
"""Temporary file wrapper
This class provides a wrapper around files opened for
temporary use. In particular, it seeks to automatically
remove the file when it is no longer needed.
def __init__(self, file, name, delete=True):
self.close_called = False
def __getattr__(self, name):
# Attribute lookups are delegated to the underlying file
# and cached for non-numeric results
# (i.e. methods are cached, closed and friends are not)
file = self.__dict__['file']
if not issubclass(type(a), type(0)):
# The underlying __enter__ method returns the wrong object
# (self.file) so override it to return the wrapper
# NT provides delete-on-close as a primitive, so we don't need
# the wrapper to do anything special. We still use it so that
# file.name is useful (i.e. not "(fdopen)") with NamedTemporaryFile.
# Cache the unlinker so we don't get spurious errors at
# shutdown when the module-level "os" is None'd out. Note
# that this must be referenced as self.unlink, because the
# name TemporaryFileWrapper may also get None'd out before
if not self.close_called:
# Need to trap __exit__ as well to ensure the file gets
# deleted when used in a with statement
def __exit__(self, exc, value, tb):
result = self.file.__exit__(exc, value, tb)
def __exit__(self, exc, value, tb):
self.file.__exit__(exc, value, tb)
def NamedTemporaryFile(mode='w+b', bufsize=-1, suffix="",
prefix=template, dir=None, delete=True):
"""Create and return a temporary file.
'prefix', 'suffix', 'dir' -- as for mkstemp.
'mode' -- the mode argument to os.fdopen (default "w+b").
'bufsize' -- the buffer size argument to os.fdopen (default -1).
'delete' -- whether the file is deleted on close (default True).
The file is created as mkstemp() would do it.
Returns an object with a file-like interface; the name of the file
is accessible as its 'name' attribute. The file will be automatically
deleted when it is closed unless the 'delete' argument is set to False.
# Setting O_TEMPORARY in the flags causes the OS to delete
# the file when it is closed. This is only supported by Windows.
if _os.name == 'nt' and delete:
(fd, name) = _mkstemp_inner(dir, prefix, suffix, flags)
file = _os.fdopen(fd, mode, bufsize)
return _TemporaryFileWrapper(file, name, delete)
if _os.name != 'posix' or _os.sys.platform == 'cygwin':
# On non-POSIX and Cygwin systems, assume that we cannot unlink a file
TemporaryFile = NamedTemporaryFile
def TemporaryFile(mode='w+b', bufsize=-1, suffix="",
prefix=template, dir=None):
"""Create and return a temporary file.
'prefix', 'suffix', 'dir' -- as for mkstemp.
'mode' -- the mode argument to os.fdopen (default "w+b").
'bufsize' -- the buffer size argument to os.fdopen (default -1).
The file is created as mkstemp() would do it.
Returns an object with a file-like interface. The file has no
name, and will cease to exist when it is closed.
It is recommended that you Edit text format, this type of Fix handles quite a lot in one request
