python module : tempfile

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tempfile

tempfile.mkstemp([suffix=’’[, prefix=‘tmp’[, dir=None[, text=False]]]])

尽可能以最安全的方式创建临时文件，文件在创建时忽略竞争条件（假定平台正确地实施了os.O_EXCL 标志 for 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 TemporaryFile(), the user of mkstemp() is responsible for deleting the temporary file when done with it.
• If suffix is not None, the file name will end with that suffix, otherwise there will be no suffix.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 not None, the file name will begin with that prefix; otherwise, a default prefix is used. The default is the return value of gettempprefix() or gettempprefixb(), as appropriate.
• If dir is not None, 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 any of suffix, prefix, and dir are not None, they must be the same type. If they are bytes, the returned name will be bytes instead of str. If you want to force a bytes return value with otherwise default behavior, pass suffix=b''.
• 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.

mkstemp() returns a tuple containing an OS-level handle to an open file (as would be returned by os.open()) and the absolute pathname of that file, in that order.

Changed in version 3.5: suffix, prefix, and dir may now be supplied in bytes in order to obtain a bytes return value. Prior to this, only str was allowed. suffix and prefix now accept and default to None to cause an appropriate default value to be used.