在Python中检查tarfile的完整性

只是在 Aya's 答案使事情变得更习惯(尽管我删除了一些错误检查,以使机制更明显):

BLOCK_SIZE = 1024

with tarfile.open("zero.tar.gz") as tardude:
    for member in tardude.getmembers():
        with tardude.extractfile(member.name) as target:
            for chunk in iter(lambda: target.read(BLOCK_SIZE), b''):
                pass

这真的只是消除了 while 1: (有时被认为是轻微的代码气味)和 if not data: 检查还要注意的是 with 将其限制为Python 2.7+

我尝试手动损坏zero.tar.gz(十六进制编辑器-编辑几个字节 中足)。第一个except没有捕获IOError。。。

如果你查看回溯,当你调用时,你会看到它被抛出 tardude.getmembers() ,所以你需要这样的东西。。。

try:
    tardude = tarfile.open("zero.tar.gz")
except:
    print "There was an error opening tarfile. The file might be corrupt or missing."

try:
    members = tardude.getmembers()
except:
    print "There was an error reading tarfile members."

for member_info in members:
    try:
        check = tardude.extractfile(member_info.name)
    except:
        print "File: %r is corrupt." % member_info.name

tardude.close()

至于最初的问题,你几乎已经解决了。你只需要从你的 check 带有类似…的对象。。。

BLOCK_SIZE = 1024

try:
    tardude = tarfile.open("zero.tar.gz")
except:
    print "There was an error opening tarfile. The file might be corrupt or missing."

try:
    members = tardude.getmembers()
except:
    print "There was an error reading tarfile members."

for member_info in members:
    try:            
        check = tardude.extractfile(member_info.name)
        while 1:
            data = check.read(BLOCK_SIZE)
            if not data:
                break
    except:
        print "File: %r is corrupt." % member_info.name

tardude.close()

…这应该确保你永远不会使用超过 BLOCK_SIZE 一次存储字节。

此外,你应该尽量避免使用。。。

try:
    do_something()
except:
    do_something_else()

…因为它会掩盖意外的异常。试着只捕捉你实际打算处理的异常,比如。。。

try:
    do_something()
except IOError:
    do_something_else()

…否则你会发现在你的代码中检测错误更加困难。

您可以使用 subprocess 要调用的模块 gzip -t 在文件上。。。

from subprocess import call
import os

with open(os.devnull, 'w') as bb:
    result = call(['gzip', '-t', "zero.tar.gz"], stdout=bb, stderr=bb)

如果 result 不是0,有问题。不过,您可能需要检查gzip是否可用。我为此写了一个实用函数;

import subprocess
import sys
import os

def checkfor(args, rv = 0):
    """Make sure that a program necessary for using this script is
    available.

    Arguments:
    args  -- string or list of strings of commands. A single string may
             not contain spaces.
    rv    -- expected return value from evoking the command.
    """
    if isinstance(args, str):
        if ' ' in args:
            raise ValueError('no spaces in single command allowed')
        args = [args]
    try:
        with open(os.devnull, 'w') as bb:
            rc = subprocess.call(args, stdout=bb, stderr=bb)
        if rc != rv:
            raise OSError
    except OSError as oops:
        outs = "Required program '{}' not found: {}."
        print(outs.format(args[0], oops.strerror))
        sys.exit(1)