python3的tempfile模块

urllib的response用到此模块所以就过来看看这个模块，
下面来读下这个模块的源码吧
1.gettempprefix
源码：

def gettempprefix():
    """The default prefix for temporary directories."""
    return template
    #template 是这个模块的一个变量 template='tmp'

功能：得到临时文件的前缀
2.gettempprefixb
源码：

def gettempprefixb():
    """The default prefix for temporary directories as bytes."""
    return _os.fsencode(gettempprefix())

功能：得到临时文件的前缀的二进制格式
3.gettempdir
源码：

tempdir = None

def gettempdir():
    """Accessor for tempfile.tempdir."""
    global tempdir
    if tempdir is None:
        _once_lock.acquire()
        try:
            if tempdir is None:
                tempdir = _get_default_tempdir()
        finally:
            _once_lock.release()
    return tempdir

功能:得到临时文件的存放目录
4.gettempdirb
源码：

def gettempdirb():
    """A bytes version of tempfile.gettempdir()."""
    return _os.fsencode(gettempdir())

功能:得到临时文件的存放目录返回二进制格式的字符串
5.mkstemp
源码:

def mkstemp(suffix=None, prefix=None, dir=None, text=False):
    """User-callable function to create and return a unique temporary
    file.  The return value is a pair (fd, name) where fd is the
    file descriptor returned by os.open, and name is the filename.

    If 'suffix' is not None, the file name will end with that suffix,
    otherwise there will be no suffix.

    If 'prefix' is not None, the file name will begin with that prefix,
    otherwise a default prefix is used.

    If 'dir' is not None, the file will be created in that directory,
    otherwise a default directory is used.

    If 'text' is specified and true, the file is opened in text
    mode.  Else (the default) the file is opened in binary mode.  On
    some operating systems, this makes no difference.

    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; str
    otherwise.

    The file is readable and writable only by the creating user ID.
    If the operating system uses permission bits to indicate whether a
    file is executable, the file is executable by no one. The file
    descriptor is not inherited by children of this process.

    Caller is responsible for deleting the file when done with it.
    """

    prefix, suffix, dir, output_type = _sanitize_params(prefix, suffix, dir)

    if text:
        flags = _text_openflags
    else:
        flags = _bin_openflags

    return _mkstemp_inner(dir, prefix, suffix, flags, output_type)

功能:
新建一个临时文件返回文件的引用和文件名

6.mkdtemp
源码：

def mkdtemp(suffix=None, prefix=None, dir=None):
    """User-callable function to create and return a unique temporary
    directory.  The return value is the pathname of the directory.

    Arguments are as for mkstemp, except that the 'text' argument is
    not accepted.

    The directory is readable, writable, and searchable only by the
    creating user.

    Caller is responsible for deleting the directory when done with it.
    """

    prefix, suffix, dir, output_type = _sanitize_params(prefix, suffix, dir)

    names = _get_candidate_names()
    if output_type is bytes:
        names = map(_os.fsencode, names)

    for seq in range(TMP_MAX):
        name = next(names)
        file = _os.path.join(dir, prefix + name + suffix)
        try:
            _os.mkdir(file, 0o700)
        except FileExistsError:
            continue    # try again
        except PermissionError:
            # This exception is thrown when a directory with the chosen name
            # already exists on windows.
            if (_os.name == 'nt' and _os.path.isdir(dir) and
                _os.access(dir, _os.W_OK)):
                continue
            else:
                raise
        return file

    raise FileExistsError(_errno.EEXIST,
                          "No usable temporary directory name found")

功能：新建一个临时目录
7.mktemp
源码:

def mktemp(suffix="", prefix=template, dir=None):
    """User-callable function to return a unique temporary file name.  The
    file is not created.

    Arguments are similar to mkstemp, except that the 'text' argument is
    not accepted, and suffix=None, prefix=None and bytes file names are not
    supported.

    THIS FUNCTION IS UNSAFE AND SHOULD NOT BE USED.  The file name may
    refer to a file that did not exist at some point, but by the time
    you get around to creating it, someone else may have beaten you to
    the punch.
    """

##    from warnings import warn as _warn
##    _warn("mktemp is a potential security risk to your program",
##          RuntimeWarning, stacklevel=2)

    if dir is None:
        dir = gettempdir()

    names = _get_candidate_names()
    for seq in range(TMP_MAX):
        name = next(names)
        file = _os.path.join(dir, prefix + name + suffix)
        if not _exists(file):
            return file

    raise FileExistsError(_errno.EEXIST,
                          "No usable temporary filename found")

功能:得到一个临时文件名，这里没有新建文件的动作，只是给你返回一个名字而已

_TemporaryFileCloser类
功能：文件关闭的类
如果不是nt平台的关闭的时候新建实例的时候可以选择关闭文件的时候是不是同时也删除文件
nt平台的话只能关闭文件不能删除，其实是对操作系统关闭文件的封装

_TemporaryFileWrapper类
通过getattr方法调用文件对象的属性，然后调用_TemporaryFileCloser的关闭文件的方法

NamedTemporaryFile|TemporaryFile创建并返回一个临时文件可以写入读取使用