Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 1 | :mod:`tempfile` --- Generate temporary files and directories |
| 2 | ============================================================ |
| 3 | |
| 4 | .. sectionauthor:: Zack Weinberg <zack@codesourcery.com> |
| 5 | |
| 6 | |
| 7 | .. module:: tempfile |
| 8 | :synopsis: Generate temporary files and directories. |
| 9 | |
| 10 | |
| 11 | .. index:: |
| 12 | pair: temporary; file name |
| 13 | pair: temporary; file |
| 14 | |
Raymond Hettinger | a199368 | 2011-01-27 01:20:32 +0000 | [diff] [blame] | 15 | **Source code:** :source:`Lib/tempfile.py` |
| 16 | |
| 17 | -------------- |
| 18 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 19 | This module generates temporary files and directories. It works on all |
Georg Brandl | e6bcc91 | 2008-05-12 18:05:20 +0000 | [diff] [blame] | 20 | supported platforms. It provides three new functions, |
| 21 | :func:`NamedTemporaryFile`, :func:`mkstemp`, and :func:`mkdtemp`, which should |
| 22 | eliminate all remaining need to use the insecure :func:`mktemp` function. |
| 23 | Temporary file names created by this module no longer contain the process ID; |
| 24 | instead a string of six random characters is used. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 25 | |
Christian Heimes | 81ee3ef | 2008-05-04 22:42:01 +0000 | [diff] [blame] | 26 | Also, all the user-callable functions now take additional arguments which |
| 27 | allow direct control over the location and name of temporary files. It is |
R David Murray | 3a420c7 | 2011-06-22 21:01:13 -0400 | [diff] [blame] | 28 | no longer necessary to use the global *tempdir* variable. |
Christian Heimes | 81ee3ef | 2008-05-04 22:42:01 +0000 | [diff] [blame] | 29 | To maintain backward compatibility, the argument order is somewhat odd; it |
| 30 | is recommended to use keyword arguments for clarity. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 31 | |
Nick Coghlan | 543af75 | 2010-10-24 11:23:25 +0000 | [diff] [blame] | 32 | The module defines the following user-callable items: |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 33 | |
Georg Brandl | 14dfede | 2010-05-21 21:12:07 +0000 | [diff] [blame] | 34 | .. function:: TemporaryFile(mode='w+b', buffering=None, encoding=None, newline=None, suffix='', prefix='tmp', dir=None) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 35 | |
Antoine Pitrou | 11cb961 | 2010-09-15 11:11:28 +0000 | [diff] [blame] | 36 | Return a :term:`file-like object` that can be used as a temporary storage area. |
Christian Heimes | 81ee3ef | 2008-05-04 22:42:01 +0000 | [diff] [blame] | 37 | The file is created using :func:`mkstemp`. It will be destroyed as soon |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 38 | as it is closed (including an implicit close when the object is garbage |
Christian Heimes | 81ee3ef | 2008-05-04 22:42:01 +0000 | [diff] [blame] | 39 | collected). Under Unix, the directory entry for the file is removed |
| 40 | immediately after the file is created. Other platforms do not support |
| 41 | this; your code should not rely on a temporary file created using this |
| 42 | function having or not having a visible name in the file system. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 43 | |
Christian Heimes | 81ee3ef | 2008-05-04 22:42:01 +0000 | [diff] [blame] | 44 | The *mode* parameter defaults to ``'w+b'`` so that the file created can |
| 45 | be read and written without being closed. Binary mode is used so that it |
| 46 | behaves consistently on all platforms without regard for the data that is |
Georg Brandl | 14dfede | 2010-05-21 21:12:07 +0000 | [diff] [blame] | 47 | stored. *buffering*, *encoding* and *newline* are interpreted as for |
| 48 | :func:`open`. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 49 | |
| 50 | The *dir*, *prefix* and *suffix* parameters are passed to :func:`mkstemp`. |
| 51 | |
Christian Heimes | 7f04431 | 2008-01-06 17:05:40 +0000 | [diff] [blame] | 52 | The returned object is a true file object on POSIX platforms. On other |
Georg Brandl | 502d9a5 | 2009-07-26 15:02:41 +0000 | [diff] [blame] | 53 | platforms, it is a file-like object whose :attr:`!file` attribute is the |
Christian Heimes | 81ee3ef | 2008-05-04 22:42:01 +0000 | [diff] [blame] | 54 | underlying true file object. This file-like object can be used in a |
Christian Heimes | 3ecfea71 | 2008-02-09 20:51:34 +0000 | [diff] [blame] | 55 | :keyword:`with` statement, just like a normal file. |
Christian Heimes | 7f04431 | 2008-01-06 17:05:40 +0000 | [diff] [blame] | 56 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 57 | |
Georg Brandl | 14dfede | 2010-05-21 21:12:07 +0000 | [diff] [blame] | 58 | .. function:: NamedTemporaryFile(mode='w+b', buffering=None, encoding=None, newline=None, suffix='', prefix='tmp', dir=None, delete=True) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 59 | |
Christian Heimes | 81ee3ef | 2008-05-04 22:42:01 +0000 | [diff] [blame] | 60 | This function operates exactly as :func:`TemporaryFile` does, except that |
| 61 | the file is guaranteed to have a visible name in the file system (on |
| 62 | Unix, the directory entry is not unlinked). That name can be retrieved |
Senthil Kumaran | a6bac95 | 2011-07-04 11:28:30 -0700 | [diff] [blame] | 63 | from the :attr:`name` attribute of the file object. Whether the name can be |
Christian Heimes | 81ee3ef | 2008-05-04 22:42:01 +0000 | [diff] [blame] | 64 | used to open the file a second time, while the named temporary file is |
| 65 | still open, varies across platforms (it can be so used on Unix; it cannot |
| 66 | on Windows NT or later). If *delete* is true (the default), the file is |
| 67 | deleted as soon as it is closed. |
Georg Brandl | 502d9a5 | 2009-07-26 15:02:41 +0000 | [diff] [blame] | 68 | The returned object is always a file-like object whose :attr:`!file` |
Christian Heimes | 81ee3ef | 2008-05-04 22:42:01 +0000 | [diff] [blame] | 69 | attribute is the underlying true file object. This file-like object can |
| 70 | be used in a :keyword:`with` statement, just like a normal file. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 71 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 72 | |
Georg Brandl | 14dfede | 2010-05-21 21:12:07 +0000 | [diff] [blame] | 73 | .. function:: SpooledTemporaryFile(max_size=0, mode='w+b', buffering=None, encoding=None, newline=None, suffix='', prefix='tmp', dir=None) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 74 | |
Christian Heimes | 81ee3ef | 2008-05-04 22:42:01 +0000 | [diff] [blame] | 75 | This function operates exactly as :func:`TemporaryFile` does, except that |
| 76 | data is spooled in memory until the file size exceeds *max_size*, or |
| 77 | until the file's :func:`fileno` method is called, at which point the |
| 78 | contents are written to disk and operation proceeds as with |
| 79 | :func:`TemporaryFile`. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 80 | |
Christian Heimes | 81ee3ef | 2008-05-04 22:42:01 +0000 | [diff] [blame] | 81 | The resulting file has one additional method, :func:`rollover`, which |
| 82 | causes the file to roll over to an on-disk file regardless of its size. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 83 | |
Christian Heimes | 81ee3ef | 2008-05-04 22:42:01 +0000 | [diff] [blame] | 84 | The returned object is a file-like object whose :attr:`_file` attribute |
Serhiy Storchaka | e79be87 | 2013-08-17 00:09:55 +0300 | [diff] [blame] | 85 | is either a :class:`io.BytesIO` or :class:`io.StringIO` object (depending on |
Serhiy Storchaka | 4b109cb | 2013-02-09 11:51:21 +0200 | [diff] [blame] | 86 | whether binary or text *mode* was specified) or a true file |
Serhiy Storchaka | 4f169a7 | 2013-02-09 11:46:42 +0200 | [diff] [blame] | 87 | object, depending on whether :func:`rollover` has been called. This |
| 88 | file-like object can be used in a :keyword:`with` statement, just like |
| 89 | a normal file. |
Christian Heimes | 81ee3ef | 2008-05-04 22:42:01 +0000 | [diff] [blame] | 90 | |
R David Murray | ca76ea1 | 2012-10-06 18:32:39 -0400 | [diff] [blame] | 91 | .. versionchanged:: 3.3 |
| 92 | the truncate method now accepts a ``size`` argument. |
| 93 | |
Christian Heimes | 81ee3ef | 2008-05-04 22:42:01 +0000 | [diff] [blame] | 94 | |
Nick Coghlan | 543af75 | 2010-10-24 11:23:25 +0000 | [diff] [blame] | 95 | .. function:: TemporaryDirectory(suffix='', prefix='tmp', dir=None) |
| 96 | |
| 97 | This function creates a temporary directory using :func:`mkdtemp` |
| 98 | (the supplied arguments are passed directly to the underlying function). |
| 99 | The resulting object can be used as a context manager (see |
R David Murray | 2368607 | 2014-02-05 14:53:40 -0500 | [diff] [blame] | 100 | :ref:`context-managers`). On completion of the context or destruction |
| 101 | of the temporary directory object the newly created temporary directory |
Nick Coghlan | 543af75 | 2010-10-24 11:23:25 +0000 | [diff] [blame] | 102 | and all its contents are removed from the filesystem. |
| 103 | |
R David Murray | 2368607 | 2014-02-05 14:53:40 -0500 | [diff] [blame] | 104 | The directory name can be retrieved from the :attr:`name` attribute of the |
| 105 | returned object. When the returned object is used as a context manager, the |
| 106 | :attr:`name` will be assigned to the target of the :keyword:`as` clause in |
| 107 | the :keyword:`with` statement, if there is one. |
Nick Coghlan | 543af75 | 2010-10-24 11:23:25 +0000 | [diff] [blame] | 108 | |
| 109 | The directory can be explicitly cleaned up by calling the |
| 110 | :func:`cleanup` method. |
| 111 | |
| 112 | .. versionadded:: 3.2 |
| 113 | |
| 114 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 115 | .. function:: mkstemp(suffix='', prefix='tmp', dir=None, text=False) |
Christian Heimes | 81ee3ef | 2008-05-04 22:42:01 +0000 | [diff] [blame] | 116 | |
| 117 | Creates a temporary file in the most secure manner possible. There are |
| 118 | no race conditions in the file's creation, assuming that the platform |
| 119 | properly implements the :const:`os.O_EXCL` flag for :func:`os.open`. The |
| 120 | file is readable and writable only by the creating user ID. If the |
| 121 | platform uses permission bits to indicate whether a file is executable, |
| 122 | the file is executable by no one. The file descriptor is not inherited |
| 123 | by child processes. |
| 124 | |
| 125 | Unlike :func:`TemporaryFile`, the user of :func:`mkstemp` is responsible |
| 126 | for deleting the temporary file when done with it. |
| 127 | |
| 128 | If *suffix* is specified, the file name will end with that suffix, |
| 129 | otherwise there will be no suffix. :func:`mkstemp` does not put a dot |
| 130 | between the file name and the suffix; if you need one, put it at the |
| 131 | beginning of *suffix*. |
| 132 | |
| 133 | If *prefix* is specified, the file name will begin with that prefix; |
| 134 | otherwise, a default prefix is used. |
| 135 | |
| 136 | If *dir* is specified, the file will be created in that directory; |
| 137 | otherwise, a default directory is used. The default directory is chosen |
| 138 | from a platform-dependent list, but the user of the application can |
| 139 | control the directory location by setting the *TMPDIR*, *TEMP* or *TMP* |
| 140 | environment variables. There is thus no guarantee that the generated |
| 141 | filename will have any nice properties, such as not requiring quoting |
| 142 | when passed to external commands via ``os.popen()``. |
| 143 | |
| 144 | If *text* is specified, it indicates whether to open the file in binary |
| 145 | mode (the default) or text mode. On some platforms, this makes no |
| 146 | difference. |
| 147 | |
| 148 | :func:`mkstemp` returns a tuple containing an OS-level handle to an open |
| 149 | file (as would be returned by :func:`os.open`) and the absolute pathname |
| 150 | of that file, in that order. |
| 151 | |
| 152 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 153 | .. function:: mkdtemp(suffix='', prefix='tmp', dir=None) |
Christian Heimes | 81ee3ef | 2008-05-04 22:42:01 +0000 | [diff] [blame] | 154 | |
| 155 | Creates a temporary directory in the most secure manner possible. There |
| 156 | are no race conditions in the directory's creation. The directory is |
| 157 | readable, writable, and searchable only by the creating user ID. |
| 158 | |
| 159 | The user of :func:`mkdtemp` is responsible for deleting the temporary |
| 160 | directory and its contents when done with it. |
| 161 | |
| 162 | The *prefix*, *suffix*, and *dir* arguments are the same as for |
| 163 | :func:`mkstemp`. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 164 | |
| 165 | :func:`mkdtemp` returns the absolute pathname of the new directory. |
| 166 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 167 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 168 | .. function:: mktemp(suffix='', prefix='tmp', dir=None) |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 169 | |
| 170 | .. deprecated:: 2.3 |
| 171 | Use :func:`mkstemp` instead. |
| 172 | |
Christian Heimes | 81ee3ef | 2008-05-04 22:42:01 +0000 | [diff] [blame] | 173 | Return an absolute pathname of a file that did not exist at the time the |
| 174 | call is made. The *prefix*, *suffix*, and *dir* arguments are the same |
| 175 | as for :func:`mkstemp`. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 176 | |
| 177 | .. warning:: |
| 178 | |
Georg Brandl | 36ab1ef | 2009-01-03 21:17:04 +0000 | [diff] [blame] | 179 | Use of this function may introduce a security hole in your program. By |
| 180 | the time you get around to doing anything with the file name it returns, |
| 181 | someone else may have beaten you to the punch. :func:`mktemp` usage can |
| 182 | be replaced easily with :func:`NamedTemporaryFile`, passing it the |
| 183 | ``delete=False`` parameter:: |
Alexandre Vassalotti | 6461e10 | 2008-05-15 22:09:29 +0000 | [diff] [blame] | 184 | |
| 185 | >>> f = NamedTemporaryFile(delete=False) |
Alexandre Vassalotti | 6461e10 | 2008-05-15 22:09:29 +0000 | [diff] [blame] | 186 | >>> f.name |
Ezio Melotti | ad17bc0 | 2013-02-22 08:28:14 +0200 | [diff] [blame] | 187 | '/tmp/tmptjujjt' |
| 188 | >>> f.write(b"Hello World!\n") |
| 189 | 13 |
Alexandre Vassalotti | 6461e10 | 2008-05-15 22:09:29 +0000 | [diff] [blame] | 190 | >>> f.close() |
| 191 | >>> os.unlink(f.name) |
| 192 | >>> os.path.exists(f.name) |
| 193 | False |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 194 | |
Christian Heimes | 81ee3ef | 2008-05-04 22:42:01 +0000 | [diff] [blame] | 195 | The module uses two global variables that tell it how to construct a |
| 196 | temporary name. They are initialized at the first call to any of the |
| 197 | functions above. The caller may change them, but this is discouraged; use |
| 198 | the appropriate function arguments, instead. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 199 | |
| 200 | |
| 201 | .. data:: tempdir |
| 202 | |
Christian Heimes | 81ee3ef | 2008-05-04 22:42:01 +0000 | [diff] [blame] | 203 | When set to a value other than ``None``, this variable defines the |
| 204 | default value for the *dir* argument to all the functions defined in this |
| 205 | module. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 206 | |
Christian Heimes | 81ee3ef | 2008-05-04 22:42:01 +0000 | [diff] [blame] | 207 | If ``tempdir`` is unset or ``None`` at any call to any of the above |
| 208 | functions, Python searches a standard list of directories and sets |
| 209 | *tempdir* to the first one which the calling user can create files in. |
| 210 | The list is: |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 211 | |
| 212 | #. The directory named by the :envvar:`TMPDIR` environment variable. |
| 213 | |
| 214 | #. The directory named by the :envvar:`TEMP` environment variable. |
| 215 | |
| 216 | #. The directory named by the :envvar:`TMP` environment variable. |
| 217 | |
| 218 | #. A platform-specific location: |
| 219 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 220 | * On Windows, the directories :file:`C:\\TEMP`, :file:`C:\\TMP`, |
| 221 | :file:`\\TEMP`, and :file:`\\TMP`, in that order. |
| 222 | |
| 223 | * On all other platforms, the directories :file:`/tmp`, :file:`/var/tmp`, and |
| 224 | :file:`/usr/tmp`, in that order. |
| 225 | |
| 226 | #. As a last resort, the current working directory. |
| 227 | |
| 228 | |
| 229 | .. function:: gettempdir() |
| 230 | |
| 231 | Return the directory currently selected to create temporary files in. If |
| 232 | :data:`tempdir` is not ``None``, this simply returns its contents; otherwise, |
| 233 | the search described above is performed, and the result returned. |
| 234 | |
| 235 | |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 236 | .. function:: gettempprefix() |
| 237 | |
| 238 | Return the filename prefix used to create temporary files. This does not |
Georg Brandl | 4b26ff8 | 2008-08-04 07:24:52 +0000 | [diff] [blame] | 239 | contain the directory component. |
Georg Brandl | 116aa62 | 2007-08-15 14:28:22 +0000 | [diff] [blame] | 240 | |
Nick Coghlan | 543af75 | 2010-10-24 11:23:25 +0000 | [diff] [blame] | 241 | |
| 242 | Examples |
| 243 | -------- |
| 244 | |
| 245 | Here are some examples of typical usage of the :mod:`tempfile` module:: |
| 246 | |
| 247 | >>> import tempfile |
| 248 | |
| 249 | # create a temporary file and write some data to it |
| 250 | >>> fp = tempfile.TemporaryFile() |
Ross Lagerwall | 810b94a | 2011-04-10 09:30:04 +0200 | [diff] [blame] | 251 | >>> fp.write(b'Hello world!') |
Nick Coghlan | 543af75 | 2010-10-24 11:23:25 +0000 | [diff] [blame] | 252 | # read data from file |
| 253 | >>> fp.seek(0) |
| 254 | >>> fp.read() |
Ross Lagerwall | 810b94a | 2011-04-10 09:30:04 +0200 | [diff] [blame] | 255 | b'Hello world!' |
Nick Coghlan | 543af75 | 2010-10-24 11:23:25 +0000 | [diff] [blame] | 256 | # close the file, it will be removed |
| 257 | >>> fp.close() |
| 258 | |
| 259 | # create a temporary file using a context manager |
| 260 | >>> with tempfile.TemporaryFile() as fp: |
Ross Lagerwall | 810b94a | 2011-04-10 09:30:04 +0200 | [diff] [blame] | 261 | ... fp.write(b'Hello world!') |
Nick Coghlan | 543af75 | 2010-10-24 11:23:25 +0000 | [diff] [blame] | 262 | ... fp.seek(0) |
| 263 | ... fp.read() |
Ross Lagerwall | 810b94a | 2011-04-10 09:30:04 +0200 | [diff] [blame] | 264 | b'Hello world!' |
Nick Coghlan | 543af75 | 2010-10-24 11:23:25 +0000 | [diff] [blame] | 265 | >>> |
| 266 | # file is now closed and removed |
| 267 | |
| 268 | # create a temporary directory using the context manager |
| 269 | >>> with tempfile.TemporaryDirectory() as tmpdirname: |
Ross Lagerwall | 810b94a | 2011-04-10 09:30:04 +0200 | [diff] [blame] | 270 | ... print('created temporary directory', tmpdirname) |
Nick Coghlan | 543af75 | 2010-10-24 11:23:25 +0000 | [diff] [blame] | 271 | >>> |
| 272 | # directory and contents have been removed |
| 273 | |