在不写入磁盘的情况下下载和解压缩.zip文件

Question

我设法使我的第一个python脚本起作用，该脚本从URL下载.ZIP文件的列表，然后继续提取ZIP文件并将其写入磁盘。

我现在无所适从，无法实现下一步。

我的主要目标是下载并提取zip文件，并通过TCP流传递内容（CSV数据）。如果可以的话，我宁愿不实际将任何zip或解压缩的文件写入磁盘。

这是我当前的脚本，可以运行，但是不幸的是必须将文件写入磁盘。

import urllib, urllister
import zipfile
import urllib2
import os
import time
import pickle

# check for extraction directories existence
if not os.path.isdir('downloaded'):
    os.makedirs('downloaded')

if not os.path.isdir('extracted'):
    os.makedirs('extracted')

# open logfile for downloaded data and save to local variable
if os.path.isfile('downloaded.pickle'):
    downloadedLog = pickle.load(open('downloaded.pickle'))
else:
    downloadedLog = {'key':'value'}

# remove entries older than 5 days (to maintain speed)

# path of zip files
zipFileURL = "http://www.thewebserver.com/that/contains/a/directory/of/zip/files"

# retrieve list of URLs from the webservers
usock = urllib.urlopen(zipFileURL)
parser = urllister.URLLister()
parser.feed(usock.read())
usock.close()
parser.close()

# only parse urls
for url in parser.urls: 
    if "PUBLIC_P5MIN" in url:

        # download the file
        downloadURL = zipFileURL + url
        outputFilename = "downloaded/" + url

        # check if file already exists on disk
        if url in downloadedLog or os.path.isfile(outputFilename):
            print "Skipping " + downloadURL
            continue

        print "Downloading ",downloadURL
        response = urllib2.urlopen(downloadURL)
        zippedData = response.read()

        # save data to disk
        print "Saving to ",outputFilename
        output = open(outputFilename,'wb')
        output.write(zippedData)
        output.close()

        # extract the data
        zfobj = zipfile.ZipFile(outputFilename)
        for name in zfobj.namelist():
            uncompressed = zfobj.read(name)

            # save uncompressed data to disk
            outputFilename = "extracted/" + name
            print "Saving extracted file to ",outputFilename
            output = open(outputFilename,'wb')
            output.write(uncompressed)
            output.close()

            # send data via tcp stream

            # file successfully downloaded and extracted store into local log and filesystem log
            downloadedLog[url] = time.time();
            pickle.dump(downloadedLog, open('downloaded.pickle', "wb" ))

Answer 1

我的建议是使用一个StringIO对象。它们模拟文件，但驻留在内存中。因此，您可以执行以下操作：

# get_zip_data() gets a zip archive containing 'foo.txt', reading 'hey, foo'

import zipfile
from StringIO import StringIO

zipdata = StringIO()
zipdata.write(get_zip_data())
myzipfile = zipfile.ZipFile(zipdata)
foofile = myzipfile.open('foo.txt')
print foofile.read()

# output: "hey, foo"

或更简单地（向Vishal致歉）：

myzipfile = zipfile.ZipFile(StringIO(get_zip_data()))
for name in myzipfile.namelist():
    [ ... ]

在Python 3中，使用BytesIO代替StringIO：

import zipfile
from io import BytesIO

filebytes = BytesIO(get_zip_data())
myzipfile = zipfile.ZipFile(filebytes)
for name in myzipfile.namelist():
    [ ... ]