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.
The default path names are returned as str. If you supply bytes as
input, all return values will be in bytes. Ex:
>>> tempfile.mkdtemp(suffix=b'')
This module also provides some data items to the user:
TMP_MAX - maximum number of names that will be tried before
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
"SpooledTemporaryFile", "TemporaryDirectory",
"mkstemp", "mkdtemp", # low level safe interfaces
"mktemp", # deprecated unsafe interface
"TMP_MAX", "gettempprefix", # constants
"gettempprefixb", "gettempdirb",
import functools as _functools
import warnings as _warnings
from random import Random as _Random
import weakref as _weakref
_allocate_lock = _thread.allocate_lock
_text_openflags = _os.O_RDWR | _os.O_CREAT | _os.O_EXCL
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'):
# This variable _was_ unused for legacy reasons, see issue 10354.
# But as of 3.5 we actually use it at runtime so changing it would
# have a possibly desirable side effect... But we do not want to support
# that as an API. It is undocumented on purpose. Do not depend on this.
_once_lock = _allocate_lock()
def _infer_return_type(*args):
"""Look at the type of all args and divine their implied return type."""
if isinstance(arg, bytes):
raise TypeError("Can't mix bytes and non-bytes in "
raise TypeError("Can't mix bytes and non-bytes in "
return str # tempfile APIs return a str by default.
def _sanitize_params(prefix, suffix, dir):
"""Common parameter processing for most APIs in this module."""
output_type = _infer_return_type(prefix, suffix, dir)
prefix = _os.fsencode(template)
return prefix, suffix, dir, output_type
class _RandomNameSequence:
"""An instance of _RandomNameSequence generates an endless
sequence of unpredictable strings which can safely be incorporated
into file names. Each string is eight characters long. Multiple
threads can safely use the same instance at the same time.
_RandomNameSequence is an iterator."""
characters = "abcdefghijklmnopqrstuvwxyz0123456789_"
if cur_pid != getattr(self, '_rng_pid', None):
letters = [choose(c) for dummy in range(8)]
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.
dirlist.extend([ _os.path.expanduser(r'~\AppData\Local\Temp'),
_os.path.expandvars(r'%SYSTEMROOT%\Temp'),
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, OSError):
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.abspath(dir)
# Try only a few names per directory.
filename = _os.path.join(dir, name)
fd = _os.open(filename, _bin_openflags, 0o600)
with _io.open(fd, 'wb', closefd=False) as fp:
# This exception is thrown when a directory with the chosen name
# already exists on windows.
if (_os.name == 'nt' and _os.path.isdir(dir) and
_os.access(dir, _os.W_OK)):
break # no point trying more names in this directory
break # no point trying more names in this directory
raise FileNotFoundError(_errno.ENOENT,
"No usable temporary directory found in %s" %
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, output_type):
"""Code common to mkstemp, TemporaryFile, and NamedTemporaryFile."""
names = _get_candidate_names()
names = map(_os.fsencode, names)
for seq in range(TMP_MAX):
file = _os.path.join(dir, pre + name + suf)
_sys.audit("tempfile.mkstemp", file)
fd = _os.open(file, flags, 0o600)
# This exception is thrown when a directory with the chosen name
# already exists on windows.
if (_os.name == 'nt' and _os.path.isdir(dir) and
_os.access(dir, _os.W_OK)):
return (fd, _os.path.abspath(file))
raise FileExistsError(_errno.EEXIST,
"No usable temporary file name found")
# User visible interfaces.
"""The default prefix for temporary directories."""
"""The default prefix for temporary directories as bytes."""
return _os.fsencode(gettempprefix())
"""Accessor for tempfile.tempdir."""
tempdir = _get_default_tempdir()
"""A bytes version of tempfile.gettempdir()."""
return _os.fsencode(gettempdir())
def mkstemp(suffix=None, prefix=None, 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 not None, the file name will end with that suffix,
otherwise there will be no suffix.
If 'prefix' is not None, the file name will begin with that prefix,
otherwise a default prefix is used.
If 'dir' is not None, 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.
If any of 'suffix', 'prefix' and 'dir' are not None, they must be the
same type. If they are bytes, the returned name will be bytes; str
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.
prefix, suffix, dir, output_type = _sanitize_params(prefix, suffix, dir)
return _mkstemp_inner(dir, prefix, suffix, flags, output_type)
def mkdtemp(suffix=None, prefix=None, 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.
prefix, suffix, dir, output_type = _sanitize_params(prefix, suffix, dir)
names = _get_candidate_names()
names = map(_os.fsencode, names)
for seq in range(TMP_MAX):
file = _os.path.join(dir, prefix + name + suffix)
_sys.audit("tempfile.mkdtemp", file)
# This exception is thrown when a directory with the chosen name
# already exists on windows.
if (_os.name == 'nt' and _os.path.isdir(dir) and
_os.access(dir, _os.W_OK)):
raise FileExistsError(_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 similar to mkstemp, except that the 'text' argument is
not accepted, and suffix=None, prefix=None and bytes file names are not
THIS FUNCTION IS UNSAFE AND SHOULD NOT BE USED. The file name may
refer 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 range(TMP_MAX):
file = _os.path.join(dir, prefix + name + suffix)
raise FileExistsError(_errno.EEXIST,
"No usable temporary filename found")
class _TemporaryFileCloser:
"""A separate object allowing proper closing of a temporary file's
underlying file object, without adding a __del__ method to the
file = None # Set here since __del__ checks it
def __init__(self, file, name, delete=True):
# 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
def close(self, unlink=_os.unlink):
if not self.close_called and self.file is not None:
# Need to ensure the file is deleted on __del__
if not self.close_called:
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._closer = _TemporaryFileCloser(file, name, delete)
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 hasattr(a, '__call__'):
def func_wrapper(*args, **kwargs):
return func(*args, **kwargs)
# Avoid closing the file as long as the wrapper is alive,
func_wrapper._closer = self._closer
if not isinstance(a, int):
# The underlying __enter__ method returns the wrong object
# (self.file) so override it to return the wrapper
# 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)
Close the temporary file, possibly deleting it.
It is recommended that you Edit text format, this type of Fix handles quite a lot in one request
