| :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 |
| |
| This module generates temporary files and directories. It works on all |
| supported platforms. It 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` member 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. |
| |
| |
| .. 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. |
| |
| |
| .. 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. |
| |
| |
| .. 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. |
| |
| |
| .. 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 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. |
| |
| |
| .. function:: gettempprefix() |
| |
| Return the filename prefix used to create temporary files. This does not |
| contain the directory component. |
| |