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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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