python - 删除临时文件的上下文管理器

Question

我正在尝试编写上下文管理器以在处理后有条件地清理临时文件。简化:

import os
from contextlib import contextmanager
from subprocess import Popen
from tempfile import NamedTemporaryFile


@contextmanager
def temp(cleanup=True):
    tmp = NamedTemporaryFile(delete=False)
    try:
        yield tmp
    finally:
        cleanup and os.remove(tmp.name)

with temp() as tmp:
    tmp.write(b'Hi')
    p = Popen(['cmd', '/c', 'type', tmp.name])
    p.wait()

尝试这个脚本引发:

Traceback (most recent call last):
  File "C:\temp\test.py", line 18, in <module>
    p.wait()
  File "C:\Python35\lib\contextlib.py", line 66, in __exit__
    next(self.gen)
  File "C:\temp\test.py", line 13, in temp
    cleanup and os.remove(tmp.name)
PermissionError: [WinError 32] The process cannot access the file because it is being used by another process: 'C:\\Temp\\tmp79su99sg'

我希望 tempfile 在 with 语句循环结束时被释放，但显然不是。

Answer 1

您可以使用 NamedTemporaryFile作为上下文管理器:

from tempfile import NamedTemporaryFile

with NamedTemporaryFile() as tmp:
    tmp.write(b'Hi')
    p = Popen(['cmd', '/c', 'type', tmp.name])
    p.wait()
# Here the file is closed and thus deleted