tempfile
— 生成临时文件和目录
¶
源代码： Lib/tempfile.py
This module generates temporary files and directories. It works on all supported platforms. It provides three new functions,
NamedTemporaryFile()
,
mkstemp()
，和
mkdtemp()
, which should eliminate all remaining need to use the insecure
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 variable. 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 items:
tempfile.
TemporaryFile
(
mode='w+b'
,
buffering=None
,
encoding=None
,
newline=None
,
suffix=''
,
prefix='tmp'
,
dir=None
)
¶
返回
像文件对象
that can be used as a temporary storage area. The file is created using
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.
buffering
,
encoding
and
newline
are interpreted as for
open()
.
The
dir
,
prefix
and
suffix
parameters are passed to
mkstemp()
.
The returned object is a true file object on POSIX platforms. On other platforms, it is a file-like object whose
file
attribute is the underlying true file object. This file-like object can be used in a
with
statement, just like a normal file.
tempfile.
NamedTemporaryFile
(
mode='w+b'
,
buffering=None
,
encoding=None
,
newline=None
,
suffix=''
,
prefix='tmp'
,
dir=None
,
delete=True
)
¶
This function operates exactly as
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
name
attribute 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
file
attribute is the underlying true file object. This file-like object can be used in a
with
statement, just like a normal file.
tempfile.
SpooledTemporaryFile
(
max_size=0
,
mode='w+b'
,
buffering=None
,
encoding=None
,
newline=None
,
suffix=''
,
prefix='tmp'
,
dir=None
)
¶
This function operates exactly as
TemporaryFile()
does, except that data is spooled in memory until the file size exceeds
max_size
, or until the file’s
fileno()
method is called, at which point the contents are written to disk and operation proceeds as with
TemporaryFile()
.
The resulting file has one additional method,
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
_file
attribute is either an
io.BytesIO
or
io.StringIO
object (depending on whether binary or text
mode
was specified) or a true file object, depending on whether
rollover()
has been called. This file-like object can be used in a
with
statement, just like a normal file.
3.3 版改变：
the truncate method now accepts a
size
自变量。
tempfile.
TemporaryDirectory
(
suffix=''
,
prefix='tmp'
,
dir=None
)
¶
This function creates a temporary directory using
mkdtemp()
(the supplied arguments are passed directly to the underlying function). The resulting object can be used as a context manager (see
with 语句上下文管理器
). On completion of the context or destruction of the temporary directory object the newly created temporary directory and all its contents are removed from the filesystem.
The directory name can be retrieved from the
name
attribute of the returned object. When the returned object is used as a context manager, the
name
will be assigned to the target of the
as
clause in the
with
statement, if there is one.
The directory can be explicitly cleaned up by calling the
cleanup()
方法。
3.2 版新增。
tempfile.
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
os.O_EXCL
标志为
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.
不像
TemporaryFile()
, the user of
mkstemp()
is responsible for deleting the temporary file when done with it.
若
suffix
is specified, 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
.
若 prefix is specified, the file name will begin with that prefix; otherwise, a default prefix is used.
若
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()
.
若 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.
tempfile.
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
mkdtemp()
is responsible for deleting the temporary directory and its contents when done with it.
The
prefix
,
suffix
，和
dir
arguments are the same as for
mkstemp()
.
mkdtemp()
返回新目录的绝对路径名。
tempfile.
mktemp
(
suffix=''
,
prefix='tmp'
,
dir=None
)
¶
从 2.3 版起弃用：
使用
mkstemp()
代替。
Return an absolute pathname of a file that did not exist at the time the call is made. The
prefix
,
suffix
，和
dir
arguments are the same as for
mkstemp()
.
警告
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.
mktemp()
usage can be replaced easily with
NamedTemporaryFile()
, passing it the
delete=False
parameter:
>>> f = NamedTemporaryFile(delete=False) >>> f.name '/tmp/tmptjujjt' >>> f.write(b"Hello World!\n") 13 >>> f.close() >>> os.unlink(f.name) >>> os.path.exists(f.name) False
The module uses a global variable 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.
tempfile.
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.
若
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:
TMPDIR
环境变量。
TEMP
环境变量。
TMP
环境变量。
C:\TEMP
,
C:\TMP
,
\TEMP
，和
\TMP
, in that order.
/tmp
,
/var/tmp
，和
/usr/tmp
, in that order.
tempfile.
gettempdir
(
)
¶
Return the directory currently selected to create temporary files in. If
tempdir
不是
None
, this simply returns its contents; otherwise, the search described above is performed, and the result returned.
tempfile.
gettempprefix
(
)
¶
Return the filename prefix used to create temporary files. This does not contain the directory component.
Here are some examples of typical usage of the
tempfile
模块：
>>> import tempfile # create a temporary file and write some data to it >>> fp = tempfile.TemporaryFile() >>> fp.write(b'Hello world!') # read data from file >>> fp.seek(0) >>> fp.read() b'Hello world!' # close the file, it will be removed >>> fp.close() # create a temporary file using a context manager >>> with tempfile.TemporaryFile() as fp: ... fp.write(b'Hello world!') ... fp.seek(0) ... fp.read() b'Hello world!' >>> # file is now closed and removed # create a temporary directory using the context manager >>> with tempfile.TemporaryDirectory() as tmpdirname: ... print('created temporary directory', tmpdirname) >>> # directory and contents have been removed