256 lines
10 KiB
ReStructuredText
256 lines
10 KiB
ReStructuredText
:mod:`tempfile` --- Generate temporary files and directories
|
|
============================================================
|
|
|
|
.. sectionauthor:: Zack Weinberg <zack@codesourcery.com>
|
|
|
|
|
|
.. module:: tempfile
|
|
:synopsis: Generate temporary files and directories.
|
|
|
|
|
|
.. index::
|
|
pair: temporary; file name
|
|
pair: temporary; file
|
|
|
|
**Source code:** :source:`Lib/tempfile.py`
|
|
|
|
--------------
|
|
|
|
This module generates temporary files and directories. It works on all
|
|
supported platforms.
|
|
|
|
In version 2.3 of Python, this module was overhauled for enhanced security. It
|
|
now provides three new functions, :func:`NamedTemporaryFile`, :func:`mkstemp`,
|
|
and :func:`mkdtemp`, which should eliminate all remaining need to use the
|
|
insecure :func:`mktemp` function. Temporary file names created by this module
|
|
no longer contain the process ID; instead a string of six random characters is
|
|
used.
|
|
|
|
Also, all the user-callable functions now take additional arguments which
|
|
allow direct control over the location and name of temporary files. It is
|
|
no longer necessary to use the global *tempdir* and *template* variables.
|
|
To maintain backward compatibility, the argument order is somewhat odd; it
|
|
is recommended to use keyword arguments for clarity.
|
|
|
|
The module defines the following user-callable functions:
|
|
|
|
|
|
.. function:: TemporaryFile([mode='w+b'[, bufsize=-1[, suffix=''[, prefix='tmp'[, dir=None]]]]])
|
|
|
|
Return a file-like object that can be used as a temporary storage area.
|
|
The file is created using :func:`mkstemp`. It will be destroyed as soon
|
|
as it is closed (including an implicit close when the object is garbage
|
|
collected). Under Unix, the directory entry for the file is removed
|
|
immediately after the file is created. Other platforms do not support
|
|
this; your code should not rely on a temporary file created using this
|
|
function having or not having a visible name in the file system.
|
|
|
|
The *mode* parameter defaults to ``'w+b'`` so that the file created can
|
|
be read and written without being closed. Binary mode is used so that it
|
|
behaves consistently on all platforms without regard for the data that is
|
|
stored. *bufsize* defaults to ``-1``, meaning that the operating system
|
|
default is used.
|
|
|
|
The *dir*, *prefix* and *suffix* parameters are passed to :func:`mkstemp`.
|
|
|
|
The returned object is a true file object on POSIX platforms. On other
|
|
platforms, it is a file-like object whose :attr:`!file` attribute is the
|
|
underlying true file object. This file-like object can be used in a
|
|
:keyword:`with` statement, just like a normal file.
|
|
|
|
|
|
.. function:: NamedTemporaryFile([mode='w+b'[, bufsize=-1[, suffix=''[, prefix='tmp'[, dir=None[, delete=True]]]]]])
|
|
|
|
This function operates exactly as :func:`TemporaryFile` does, except that
|
|
the file is guaranteed to have a visible name in the file system (on
|
|
Unix, the directory entry is not unlinked). That name can be retrieved
|
|
from the :attr:`name` attribute of the file object. Whether the name can be
|
|
used to open the file a second time, while the named temporary file is
|
|
still open, varies across platforms (it can be so used on Unix; it cannot
|
|
on Windows NT or later). If *delete* is true (the default), the file is
|
|
deleted as soon as it is closed.
|
|
|
|
The returned object is always a file-like object whose :attr:`!file`
|
|
attribute is the underlying true file object. This file-like object can
|
|
be used in a :keyword:`with` statement, just like a normal file.
|
|
|
|
.. versionadded:: 2.3
|
|
|
|
.. versionadded:: 2.6
|
|
The *delete* parameter.
|
|
|
|
|
|
.. function:: SpooledTemporaryFile([max_size=0, [mode='w+b'[, bufsize=-1[, suffix=''[, prefix='tmp'[, dir=None]]]]]])
|
|
|
|
This function operates exactly as :func:`TemporaryFile` does, except that
|
|
data is spooled in memory until the file size exceeds *max_size*, or
|
|
until the file's :func:`fileno` method is called, at which point the
|
|
contents are written to disk and operation proceeds as with
|
|
:func:`TemporaryFile`.
|
|
|
|
The resulting file has one additional method, :func:`rollover`, which
|
|
causes the file to roll over to an on-disk file regardless of its size.
|
|
|
|
The returned object is a file-like object whose :attr:`_file` attribute
|
|
is either a :class:`StringIO` object or a true file object, depending on
|
|
whether :func:`rollover` has been called. This file-like object can be
|
|
used in a :keyword:`with` statement, just like a normal file.
|
|
|
|
.. versionadded:: 2.6
|
|
|
|
|
|
.. function:: mkstemp([suffix=''[, prefix='tmp'[, dir=None[, text=False]]]])
|
|
|
|
Creates a temporary file in the most secure manner possible. There are
|
|
no race conditions in the file's creation, assuming that the platform
|
|
properly implements the :const:`os.O_EXCL` flag for :func:`os.open`. The
|
|
file is readable and writable only by the creating user ID. If the
|
|
platform uses permission bits to indicate whether a file is executable,
|
|
the file is executable by no one. The file descriptor is not inherited
|
|
by child processes.
|
|
|
|
Unlike :func:`TemporaryFile`, the user of :func:`mkstemp` is responsible
|
|
for deleting the temporary file when done with it.
|
|
|
|
If *suffix* is specified, the file name will end with that suffix,
|
|
otherwise there will be no suffix. :func:`mkstemp` does not put a dot
|
|
between the file name and the suffix; if you need one, put it at the
|
|
beginning of *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. The default directory is chosen
|
|
from a platform-dependent list, but the user of the application can
|
|
control the directory location by setting the *TMPDIR*, *TEMP* or *TMP*
|
|
environment variables. There is thus no guarantee that the generated
|
|
filename will have any nice properties, such as not requiring quoting
|
|
when passed to external commands via ``os.popen()``.
|
|
|
|
If *text* is specified, it indicates whether to open the file in binary
|
|
mode (the default) or text mode. On some platforms, this makes no
|
|
difference.
|
|
|
|
:func:`mkstemp` returns a tuple containing an OS-level handle to an open
|
|
file (as would be returned by :func:`os.open`) and the absolute pathname
|
|
of that file, in that order.
|
|
|
|
.. versionadded:: 2.3
|
|
|
|
|
|
.. function:: mkdtemp([suffix=''[, prefix='tmp'[, dir=None]]])
|
|
|
|
Creates a temporary directory in the most secure manner possible. There
|
|
are no race conditions in the directory's creation. The directory is
|
|
readable, writable, and searchable only by the creating user ID.
|
|
|
|
The user of :func:`mkdtemp` is responsible for deleting the temporary
|
|
directory and its contents when done with it.
|
|
|
|
The *prefix*, *suffix*, and *dir* arguments are the same as for
|
|
:func:`mkstemp`.
|
|
|
|
:func:`mkdtemp` returns the absolute pathname of the new directory.
|
|
|
|
.. versionadded:: 2.3
|
|
|
|
|
|
.. function:: mktemp([suffix=''[, prefix='tmp'[, dir=None]]])
|
|
|
|
.. deprecated:: 2.3
|
|
Use :func:`mkstemp` instead.
|
|
|
|
Return an absolute pathname of a file that did not exist at the time the
|
|
call is made. The *prefix*, *suffix*, and *dir* arguments are the same
|
|
as for :func:`mkstemp`.
|
|
|
|
.. warning::
|
|
|
|
Use of this function may introduce a security hole in your program. By
|
|
the time you get around to doing anything with the file name it returns,
|
|
someone else may have beaten you to the punch. :func:`mktemp` usage can
|
|
be replaced easily with :func:`NamedTemporaryFile`, passing it the
|
|
``delete=False`` parameter::
|
|
|
|
>>> f = NamedTemporaryFile(delete=False)
|
|
>>> f
|
|
<open file '<fdopen>', mode 'w+b' at 0x384698>
|
|
>>> f.name
|
|
'/var/folders/5q/5qTPn6xq2RaWqk+1Ytw3-U+++TI/-Tmp-/tmpG7V1Y0'
|
|
>>> f.write("Hello World!\n")
|
|
>>> f.close()
|
|
>>> os.unlink(f.name)
|
|
>>> os.path.exists(f.name)
|
|
False
|
|
|
|
The module uses two global variables that tell it how to construct a
|
|
temporary name. They are initialized at the first call to any of the
|
|
functions above. The caller may change them, but this is discouraged; use
|
|
the appropriate function arguments, instead.
|
|
|
|
|
|
.. data:: tempdir
|
|
|
|
When set to a value other than ``None``, this variable defines the
|
|
default value for the *dir* argument to all the functions defined in this
|
|
module.
|
|
|
|
If ``tempdir`` is unset or ``None`` at any call to any of the above
|
|
functions, Python searches a standard list of directories and sets
|
|
*tempdir* to the first one which the calling user can create files in.
|
|
The list is:
|
|
|
|
#. The directory named by the :envvar:`TMPDIR` environment variable.
|
|
|
|
#. The directory named by the :envvar:`TEMP` environment variable.
|
|
|
|
#. The directory named by the :envvar:`TMP` environment variable.
|
|
|
|
#. A platform-specific location:
|
|
|
|
* On RiscOS, the directory named by the :envvar:`Wimp$ScrapDir` environment
|
|
variable.
|
|
|
|
* On Windows, the directories :file:`C:\\TEMP`, :file:`C:\\TMP`,
|
|
:file:`\\TEMP`, and :file:`\\TMP`, in that order.
|
|
|
|
* On all other platforms, the directories :file:`/tmp`, :file:`/var/tmp`, and
|
|
:file:`/usr/tmp`, in that order.
|
|
|
|
#. As a last resort, the current working directory.
|
|
|
|
|
|
.. function:: gettempdir()
|
|
|
|
Return the directory currently selected to create temporary files in. If
|
|
:data:`tempdir` is not ``None``, this simply returns its contents; otherwise,
|
|
the search described above is performed, and the result returned.
|
|
|
|
.. versionadded:: 2.3
|
|
|
|
|
|
.. data:: template
|
|
|
|
.. deprecated:: 2.0
|
|
Use :func:`gettempprefix` instead.
|
|
|
|
When set to a value other than ``None``, this variable defines the prefix of the
|
|
final component of the filenames returned by :func:`mktemp`. A string of six
|
|
random letters and digits is appended to the prefix to make the filename unique.
|
|
The default prefix is :file:`tmp`.
|
|
|
|
Older versions of this module used to require that ``template`` be set to
|
|
``None`` after a call to :func:`os.fork`; this has not been necessary since
|
|
version 1.5.2.
|
|
|
|
|
|
.. function:: gettempprefix()
|
|
|
|
Return the filename prefix used to create temporary files. This does not
|
|
contain the directory component. Using this function is preferred over reading
|
|
the *template* variable directly.
|
|
|
|
.. versionadded:: 1.5.2
|
|
|