Question

我在使用python的内置库gzip时遇到了一些问题。仔细查看了关于它的几乎所有其他堆栈问题，它们似乎都没有工作。

我的问题是，当我尝试解体时，我得到了IOError

我正在：

Traceback (most recent call last):
File "mymodule.py", line 61, in
  return gz.read()
File "/usr/lib/python2.7/gzip.py", line 245,
  readself._read(readsize)
File "/usr/lib/python2.7/gzip.py", line 287, in
  _readself._read_gzip_header()
File "/usr/lib/python2.7/gzip.py", line 181, in
  _read_gzip_header
raise IOError, 'Not a gzipped file'IOError: Not a gzipped file

这是我通过网络发送它的代码，为什么我做事情可能没有意义，但它通常在一个while循环和内存效率，我只是简化它。

buffer = cStringIO.StringIO(output) #output is from a subprocess call
small_buffer = cStringIO.StringIO()
small_string = buffer.read() #need a string to write to buffer 
gzip_obj = gzip.GzipFile(fileobj=small_buffer,compresslevel=6, mode='wb')
gzip_obj.write(small_string)
compressed_str = small_buffer.getvalue()

blowfish = Blowfish.new('abcd', Blowfish.MODE_ECB)
remainder = '|'*(8 - (len(compressed_str) % 8))
compressed_str += remainder
encrypted = blowfish.encrypt(compressed_str)
#i send it over smb, then retrieve it later

然后这是检索它的代码：

#buffer is a cStringIO object filled with data from  retrieval
decrypter = Blowfish.new('abcd', Blowfish.MODE_ECB)
value = buffer.getvalue()
decrypted = decrypter.decrypt(value)
buff = cStringIO.StringIO(decrypted)
buff.seek(0)
gz = gzip.GzipFile(fileobj=buff)
return gz.read()

这是问题

return gz.read()

Answer 1

编辑： 我想......你在解压缩之前忘了删除填充。下面的代码对我有用，如果我不删除填充，则会给出同样的错误。

编辑2： 填充规范：你做填充的方式我认为需要你传递填充的大小，因为我认为加密算法可以使用管道性格也。根据{{3}}，您应该填充所需填充字节数的二进制表示（不是ASCII数字）。我已经更新了下面的代码来解释规范。

import gzip
import cStringIO
from Crypto.Cipher import Blowfish

#gzip and encrypt
small_buffer = cStringIO.StringIO()
small_string = "test data"
with gzip.GzipFile(fileobj=small_buffer,compresslevel=6, mode='wb') as gzip_obj:
    gzip_obj.write(small_string)
compressed_str = small_buffer.getvalue()
blowfish = Blowfish.new('better than bad')
#remainder = '|'*(8 - (len(compressed_str) % 8))
pad_bytes = 8 - (len(compressed_str) % 8)
padding = chr(pad_bytes)*pad_bytes
compressed_str += padding
encrypted = blowfish.encrypt(compressed_str)
print("encrypted: {}".format(encrypted))



#decrypt and ungzip (pretending to be in a separate space here)
value = encrypted
blowfish = Blowfish.new('better than bad')
decrypted = blowfish.decrypt(value)
buff = cStringIO.StringIO(decrypted)
buff.seek(-1,2) #move to the last byte
pad_bytes = ord(buff.read(1)) #get the size of the padding from the last byte
buff.truncate(len(buff.getvalue()) - pad_bytes) #probably a better way to do this.
buff.seek(0)
with gzip.GzipFile(fileobj=buff) as gz:
    back_home = gz.read()
print("back home: {}".format(back_home))

Python IOError：不是gzip文件（Gzip和Blowfish加密/压缩）

这是问题

1 个答案: