Extracting a zipfile to memory?

问题

How do I extract a zip to memory?

My attempt (returning None on .getvalue()):

from zipfile import ZipFile
from StringIO import StringIO

def extract_zip(input_zip):
    return StringIO(ZipFile(input_zip).extractall())

回答1:

extractall extracts to the file system, so you won't get what you want. To extract a file in memory, use the ZipFile.read() method.

If you really need the full content in memory, you could do something like:

def extract_zip(input_zip):
    input_zip=ZipFile(input_zip)
    return {name: input_zip.read(name) for name in input_zip.namelist()}

回答2:

Frequently working with in-memory archives in Python 2 I would recommend making a tool. Something like this:

import zipfile
import StringIO

class InMemoryZip(object):
   def __init__(self):
       # Create the in-memory file-like object for working w/imz
       self.in_memory_zip = StringIO.StringIO()

   # Just zip it, zip it
   def append(self, filename_in_zip, file_contents):
       # Appends a file with name filename_in_zip and contents of
       # file_contents to the in-memory zip.
       # Get a handle to the in-memory zip in append mode
       zf = zipfile.ZipFile(self.in_memory_zip, "a", zipfile.ZIP_DEFLATED, False)

       # Write the file to the in-memory zip
       zf.writestr(filename_in_zip, file_contents)

       # Mark the files as having been created on Windows so that
       # Unix permissions are not inferred as 0000
       for zfile in zf.filelist:
           zfile.create_system = 0       

       return self

   def read(self):
       # Returns a string with the contents of the in-memory zip.
       self.in_memory_zip.seek(0)
       return self.in_memory_zip.read()

   # Zip it, zip it, zip it
   def writetofile(self, filename):
       # Writes the in-memory zip to a file.
       f = file(filename, "wb")
       f.write(self.read())
       f.close()

if __name__ == "__main__":
   # Run a test
   imz = InMemoryZip()
   imz.append("testfile.txt", "Make a test").append("testfile2.txt", "And another one")
   imz.writetofile("testfile.zip")