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| 55 | <H1><A NAME="SECTION0082200000000000000000"> |
| 56 | 6.22 <tt class="module">tempfile</tt> -- |
| 57 | Generate temporary files and directories</A> |
| 58 | </H1> |
| 59 | |
| 60 | <P> |
| 61 | <A NAME="module-tempfile"></A> |
| 62 | |
| 63 | <P> |
| 64 | <a id='l2h-2199' xml:id='l2h-2199'></a><a id='l2h-2200' xml:id='l2h-2200'></a> |
| 65 | <P> |
| 66 | This module generates temporary files and directories. It works on |
| 67 | all supported platforms. |
| 68 | |
| 69 | <P> |
| 70 | In version 2.3 of Python, this module was overhauled for enhanced |
| 71 | security. It now provides three new functions, |
| 72 | <tt class="function">NamedTemporaryFile()</tt>, <tt class="function">mkstemp()</tt>, and |
| 73 | <tt class="function">mkdtemp()</tt>, which should eliminate all remaining need to use |
| 74 | the insecure <tt class="function">mktemp()</tt> function. Temporary file names created |
| 75 | by this module no longer contain the process ID; instead a string of |
| 76 | six random characters is used. |
| 77 | |
| 78 | <P> |
| 79 | Also, all the user-callable functions now take additional arguments |
| 80 | which allow direct control over the location and name of temporary |
| 81 | files. It is no longer necessary to use the global <var>tempdir</var> and |
| 82 | <var>template</var> variables. To maintain backward compatibility, the |
| 83 | argument order is somewhat odd; it is recommended to use keyword |
| 84 | arguments for clarity. |
| 85 | |
| 86 | <P> |
| 87 | The module defines the following user-callable functions: |
| 88 | |
| 89 | <P> |
| 90 | <dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"> |
| 91 | <td><nobr><b><tt id='l2h-2201' xml:id='l2h-2201' class="function">TemporaryFile</tt></b>(</nobr></td> |
| 92 | <td><var></var><big>[</big><var>mode=<code>'w+b'</code></var><big>[</big><var>, |
| 93 | bufsize=<code>-1</code></var><big>[</big><var>, |
| 94 | suffix</var><big>[</big><var>, prefix</var><big>[</big><var>, dir</var><big>]</big><var></var><big>]</big><var></var><big>]</big><var></var><big>]</big><var></var><big>]</big><var></var>)</td></tr></table></dt> |
| 95 | <dd> |
| 96 | Return a file (or file-like) object that can be used as a temporary |
| 97 | storage area. The file is created using <tt class="function">mkstemp</tt>. It will |
| 98 | be destroyed as soon as it is closed (including an implicit close when |
| 99 | the object is garbage collected). Under <span class="Unix">Unix</span>, the directory entry |
| 100 | for the file is removed immediately after the file is created. Other |
| 101 | platforms do not support this; your code should not rely on a |
| 102 | temporary file created using this function having or not having a |
| 103 | visible name in the file system. |
| 104 | |
| 105 | <P> |
| 106 | The <var>mode</var> parameter defaults to <code>'w+b'</code> so that the file |
| 107 | created can be read and written without being closed. Binary mode is |
| 108 | used so that it behaves consistently on all platforms without regard |
| 109 | for the data that is stored. <var>bufsize</var> defaults to <code>-1</code>, |
| 110 | meaning that the operating system default is used. |
| 111 | |
| 112 | <P> |
| 113 | The <var>dir</var>, <var>prefix</var> and <var>suffix</var> parameters are passed to |
| 114 | <tt class="function">mkstemp()</tt>. |
| 115 | </dl> |
| 116 | |
| 117 | <P> |
| 118 | <dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"> |
| 119 | <td><nobr><b><tt id='l2h-2202' xml:id='l2h-2202' class="function">NamedTemporaryFile</tt></b>(</nobr></td> |
| 120 | <td><var></var><big>[</big><var>mode=<code>'w+b'</code></var><big>[</big><var>, |
| 121 | bufsize=<code>-1</code></var><big>[</big><var>, |
| 122 | suffix</var><big>[</big><var>, prefix</var><big>[</big><var>, |
| 123 | dir</var><big>]</big><var></var><big>]</big><var></var><big>]</big><var></var><big>]</big><var></var><big>]</big><var></var>)</td></tr></table></dt> |
| 124 | <dd> |
| 125 | This function operates exactly as <tt class="function">TemporaryFile()</tt> does, |
| 126 | except that the file is guaranteed to have a visible name in the file |
| 127 | system (on <span class="Unix">Unix</span>, the directory entry is not unlinked). That name can |
| 128 | be retrieved from the <tt class="member">name</tt> member of the file object. Whether |
| 129 | the name can be used to open the file a second time, while the |
| 130 | named temporary file is still open, varies across platforms (it can |
| 131 | be so used on <span class="Unix">Unix</span>; it cannot on Windows NT or later). |
| 132 | |
| 133 | <span class="versionnote">New in version 2.3.</span> |
| 134 | |
| 135 | </dl> |
| 136 | |
| 137 | <P> |
| 138 | <dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"> |
| 139 | <td><nobr><b><tt id='l2h-2203' xml:id='l2h-2203' class="function">mkstemp</tt></b>(</nobr></td> |
| 140 | <td><var></var><big>[</big><var>suffix</var><big>[</big><var>, |
| 141 | prefix</var><big>[</big><var>, dir</var><big>[</big><var>, text</var><big>]</big><var></var><big>]</big><var></var><big>]</big><var></var><big>]</big><var></var>)</td></tr></table></dt> |
| 142 | <dd> |
| 143 | Creates a temporary file in the most secure manner possible. There |
| 144 | are no race conditions in the file's creation, assuming that the |
| 145 | platform properly implements the <tt class="constant">O_EXCL</tt> flag for |
| 146 | <tt class="function">os.open()</tt>. The file is readable and writable only by the |
| 147 | creating user ID. If the platform uses permission bits to indicate |
| 148 | whether a file is executable, the file is executable by no one. The |
| 149 | file descriptor is not inherited by child processes. |
| 150 | |
| 151 | <P> |
| 152 | Unlike <tt class="function">TemporaryFile()</tt>, the user of <tt class="function">mkstemp()</tt> is |
| 153 | responsible for deleting the temporary file when done with it. |
| 154 | |
| 155 | <P> |
| 156 | If <var>suffix</var> is specified, the file name will end with that suffix, |
| 157 | otherwise there will be no suffix. <tt class="function">mkstemp()</tt> does not put a |
| 158 | dot between the file name and the suffix; if you need one, put it at |
| 159 | the beginning of <var>suffix</var>. |
| 160 | |
| 161 | <P> |
| 162 | If <var>prefix</var> is specified, the file name will begin with that |
| 163 | prefix; otherwise, a default prefix is used. |
| 164 | |
| 165 | <P> |
| 166 | If <var>dir</var> is specified, the file will be created in that directory; |
| 167 | otherwise, a default directory is used. |
| 168 | |
| 169 | <P> |
| 170 | If <var>text</var> is specified, it indicates whether to open the file in |
| 171 | binary mode (the default) or text mode. On some platforms, this makes |
| 172 | no difference. |
| 173 | |
| 174 | <P> |
| 175 | <tt class="function">mkstemp()</tt> returns a tuple containing an OS-level handle to |
| 176 | an open file (as would be returned by <tt class="function">os.open()</tt>) and the |
| 177 | absolute pathname of that file, in that order. |
| 178 | |
| 179 | <span class="versionnote">New in version 2.3.</span> |
| 180 | |
| 181 | </dl> |
| 182 | |
| 183 | <P> |
| 184 | <dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"> |
| 185 | <td><nobr><b><tt id='l2h-2204' xml:id='l2h-2204' class="function">mkdtemp</tt></b>(</nobr></td> |
| 186 | <td><var></var><big>[</big><var>suffix</var><big>[</big><var>, prefix</var><big>[</big><var>, dir</var><big>]</big><var></var><big>]</big><var></var><big>]</big><var></var>)</td></tr></table></dt> |
| 187 | <dd> |
| 188 | Creates a temporary directory in the most secure manner possible. |
| 189 | There are no race conditions in the directory's creation. The |
| 190 | directory is readable, writable, and searchable only by the |
| 191 | creating user ID. |
| 192 | |
| 193 | <P> |
| 194 | The user of <tt class="function">mkdtemp()</tt> is responsible for deleting the |
| 195 | temporary directory and its contents when done with it. |
| 196 | |
| 197 | <P> |
| 198 | The <var>prefix</var>, <var>suffix</var>, and <var>dir</var> arguments are the same |
| 199 | as for <tt class="function">mkstemp()</tt>. |
| 200 | |
| 201 | <P> |
| 202 | <tt class="function">mkdtemp()</tt> returns the absolute pathname of the new directory. |
| 203 | |
| 204 | <span class="versionnote">New in version 2.3.</span> |
| 205 | |
| 206 | </dl> |
| 207 | |
| 208 | <P> |
| 209 | <dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"> |
| 210 | <td><nobr><b><tt id='l2h-2205' xml:id='l2h-2205' class="function">mktemp</tt></b>(</nobr></td> |
| 211 | <td><var></var><big>[</big><var>suffix</var><big>[</big><var>, prefix</var><big>[</big><var>, dir</var><big>]</big><var></var><big>]</big><var></var><big>]</big><var></var>)</td></tr></table></dt> |
| 212 | <dd> |
| 213 | <div class="versionnote"><b>Deprecated since release 2.3.</b> |
| 214 | Use <tt class="function">mkstemp()</tt> instead.</div><p></p> |
| 215 | Return an absolute pathname of a file that did not exist at the time |
| 216 | the call is made. The <var>prefix</var>, <var>suffix</var>, and <var>dir</var> |
| 217 | arguments are the same as for <tt class="function">mkstemp()</tt>. |
| 218 | |
| 219 | <P> |
| 220 | <span class="warning"><b class="label">Warning:</b> |
| 221 | Use of this function may introduce a security hole in your |
| 222 | program. By the time you get around to doing anything with the file |
| 223 | name it returns, someone else may have beaten you to the punch.</span> |
| 224 | </dl> |
| 225 | |
| 226 | <P> |
| 227 | The module uses two global variables that tell it how to construct a |
| 228 | temporary name. They are initialized at the first call to any of the |
| 229 | functions above. The caller may change them, but this is discouraged; |
| 230 | use the appropriate function arguments, instead. |
| 231 | |
| 232 | <P> |
| 233 | <dl><dt><b><tt id='l2h-2206' xml:id='l2h-2206'>tempdir</tt></b></dt> |
| 234 | <dd> |
| 235 | When set to a value other than <code>None</code>, this variable defines the |
| 236 | default value for the <var>dir</var> argument to all the functions defined |
| 237 | in this module. |
| 238 | |
| 239 | <P> |
| 240 | If <code>tempdir</code> is unset or <code>None</code> at any call to any of the |
| 241 | above functions, Python searches a standard list of directories and |
| 242 | sets <var>tempdir</var> to the first one which the calling user can create |
| 243 | files in. The list is: |
| 244 | |
| 245 | <P> |
| 246 | |
| 247 | <OL> |
| 248 | <LI>The directory named by the <a class="envvar" id='l2h-2210' xml:id='l2h-2210'>TMPDIR</a> environment variable. |
| 249 | </LI> |
| 250 | <LI>The directory named by the <a class="envvar" id='l2h-2211' xml:id='l2h-2211'>TEMP</a> environment variable. |
| 251 | </LI> |
| 252 | <LI>The directory named by the <a class="envvar" id='l2h-2212' xml:id='l2h-2212'>TMP</a> environment variable. |
| 253 | </LI> |
| 254 | <LI>A platform-specific location: |
| 255 | |
| 256 | <UL> |
| 257 | <LI>On RiscOS, the directory named by the |
| 258 | <a class="envvar" id='l2h-2213' xml:id='l2h-2213'>Wimp$ScrapDir</a> environment variable. |
| 259 | </LI> |
| 260 | <LI>On Windows, the directories |
| 261 | <span class="file">C:<SPAN CLASS="MATH"><IMG |
| 262 | WIDTH="12" HEIGHT="32" ALIGN="MIDDLE" BORDER="0" |
| 263 | SRC="img2.png" |
| 264 | ALT="$\backslash$"></SPAN>TEMP</span>, |
| 265 | <span class="file">C:<SPAN CLASS="MATH"><IMG |
| 266 | WIDTH="12" HEIGHT="32" ALIGN="MIDDLE" BORDER="0" |
| 267 | SRC="img2.png" |
| 268 | ALT="$\backslash$"></SPAN>TMP</span>, |
| 269 | <span class="file"><SPAN CLASS="MATH"><IMG |
| 270 | WIDTH="12" HEIGHT="32" ALIGN="MIDDLE" BORDER="0" |
| 271 | SRC="img2.png" |
| 272 | ALT="$\backslash$"></SPAN>TEMP</span>, and |
| 273 | <span class="file"><SPAN CLASS="MATH"><IMG |
| 274 | WIDTH="12" HEIGHT="32" ALIGN="MIDDLE" BORDER="0" |
| 275 | SRC="img2.png" |
| 276 | ALT="$\backslash$"></SPAN>TMP</span>, in that order. |
| 277 | </LI> |
| 278 | <LI>On all other platforms, the directories |
| 279 | <span class="file">/tmp</span>, <span class="file">/var/tmp</span>, and <span class="file">/usr/tmp</span>, in that order. |
| 280 | |
| 281 | </LI> |
| 282 | </UL> |
| 283 | </LI> |
| 284 | <LI>As a last resort, the current working directory. |
| 285 | </LI> |
| 286 | </OL> |
| 287 | </dd></dl> |
| 288 | |
| 289 | <P> |
| 290 | <dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"> |
| 291 | <td><nobr><b><tt id='l2h-2207' xml:id='l2h-2207' class="function">gettempdir</tt></b>(</nobr></td> |
| 292 | <td><var></var>)</td></tr></table></dt> |
| 293 | <dd> |
| 294 | Return the directory currently selected to create temporary files in. |
| 295 | If <code>tempdir</code> is not <code>None</code>, this simply returns its contents; |
| 296 | otherwise, the search described above is performed, and the result |
| 297 | returned. |
| 298 | </dl> |
| 299 | |
| 300 | <P> |
| 301 | <dl><dt><b><tt id='l2h-2208' xml:id='l2h-2208'>template</tt></b></dt> |
| 302 | <dd> |
| 303 | <div class="versionnote"><b>Deprecated since release 2.0.</b> |
| 304 | Use <tt class="function">gettempprefix()</tt> instead.</div><p></p> |
| 305 | When set to a value other than <code>None</code>, this variable defines the |
| 306 | prefix of the final component of the filenames returned by |
| 307 | <tt class="function">mktemp()</tt>. A string of six random letters and digits is |
| 308 | appended to the prefix to make the filename unique. On Windows, |
| 309 | the default prefix is <span class="file">~T</span>; on all other systems |
| 310 | it is <span class="file">tmp</span>. |
| 311 | |
| 312 | <P> |
| 313 | Older versions of this module used to require that <code>template</code> be |
| 314 | set to <code>None</code> after a call to <tt class="function">os.fork()</tt>; this has not |
| 315 | been necessary since version 1.5.2. |
| 316 | </dd></dl> |
| 317 | |
| 318 | <P> |
| 319 | <dl><dt><table cellpadding="0" cellspacing="0"><tr valign="baseline"> |
| 320 | <td><nobr><b><tt id='l2h-2209' xml:id='l2h-2209' class="function">gettempprefix</tt></b>(</nobr></td> |
| 321 | <td><var></var>)</td></tr></table></dt> |
| 322 | <dd> |
| 323 | Return the filename prefix used to create temporary files. This does |
| 324 | not contain the directory component. Using this function is preferred |
| 325 | over reading the <var>template</var> variable directly. |
| 326 | |
| 327 | <span class="versionnote">New in version 1.5.2.</span> |
| 328 | |
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