Python解压缩字节流？

Question

情况如下:

• 我从Amazon S3获取gzip xml文档

  import boto
  from boto.s3.connection import S3Connection
  from boto.s3.key import Key
  conn = S3Connection('access Id', 'secret access key')
  b = conn.get_bucket('mydev.myorg')
  k = Key(b)
  k.key('documents/document.xml.gz')
  

• 我把它们作为文件阅读

  import gzip
  f = open('/tmp/p', 'w')
  k.get_file(f)
  f.close()
  r = gzip.open('/tmp/p', 'rb')
  file_content = r.read()
  r.close()
  

题

如何直接解压缩流并读取内容？

我不想创建临时文件,它们看起来不太好.

Answer 1

是的,您可以使用该zlib模块解压缩字节流:

import zlib

def stream_gzip_decompress(stream):
    dec = zlib.decompressobj(32 + zlib.MAX_WBITS)  # offset 32 to skip the header
    for chunk in stream:
        rv = dec.decompress(chunk)
        if rv:
            yield rv

32个信号偏移到zlibgzip标头预期但跳过的标头.

S3密钥对象是一个迭代器,因此您可以:

for data in stream_gzip_decompress(k):
    # do something with the decompressed data

Answer 2

我必须做同样的事情,这就是我做到的:

import gzip
f = StringIO.StringIO()
k.get_file(f)
f.seek(0) #This is crucial
gzf = gzip.GzipFile(fileobj=f)
file_content = gzf.read()

Answer 3

对于 Python3x 和 boto3-

所以我使用 BytesIO 将压缩文件读入缓冲区对象，然后我使用 zipfile 将解压缩流作为未压缩数据打开，我能够逐行获取数据。

import io
import zipfile
import boto3
import sys

s3 = boto3.resource('s3', 'us-east-1')


def stream_zip_file():
    count = 0
    obj = s3.Object(
        bucket_name='MonkeyBusiness',
        key='/Daily/Business/Banana/{current-date}/banana.zip'
    )
    buffer = io.BytesIO(obj.get()["Body"].read())
    print (buffer)
    z = zipfile.ZipFile(buffer)
    foo2 = z.open(z.infolist()[0])
    print(sys.getsizeof(foo2))
    line_counter = 0
    for _ in foo2:
        line_counter += 1
    print (line_counter)
    z.close()


if __name__ == '__main__':
    stream_zip_file()