python3安装包是说解压数据出错怎么办_python zlib解压缩gzip数据流出错的解决方法...

zlib解压缩gzip数据，经常报如下错误：

Error -3 while decompressing data: incorrect header check

错误提示信息很明确，就是解压缩时检测到头部不正确

这是因为你的数据可能是如下格式：

deflate

zlib

gzip

需要分别按如下方式来解压缩：

deflate: wbits = -zlib.MAX_WBITS

zlib: wbits = zlib.MAX_WBITS

gzip: wbits = zlib.MAX_WBITS | 16

当然还有头部自动检测的解压方法

参考如下代码：

#-*- coding=utf-8 -*-

#!/usr/bin/env python

import zlib

deflate_compress = zlib.compressobj(9, zlib.DEFLATED, -zlib.MAX_WBITS)

zlib_compress = zlib.compressobj(9, zlib.DEFLATED, zlib.MAX_WBITS)

gzip_compress = zlib.compressobj(9, zlib.DEFLATED, zlib.MAX_WBITS | 16)

text = '''test'''

deflate_data = deflate_compress.compress(text) + deflate_compress.flush()

zlib_data = zlib_compress.compress(text) + zlib_compress.flush()

gzip_data = gzip_compress.compress(text) + gzip_compress.flush()

print "1," + zlib.decompress(zlib_data)

try:

print "21," + zlib.decompress(deflate_data)

except Exception, e:

print "22," + repr( e )

print "23," + zlib.decompress(deflate_data, -zlib.MAX_WBITS)

try:

print "31," + zlib.decompress(gzip_data)

except Exception, e:

print "32," + repr( e )

print "33," + zlib.decompress(gzip_data, zlib.MAX_WBITS|16)

# 头部自动检测

print "41," + zlib.decompress(gzip_data, zlib.MAX_WBITS|32)

print "42," + zlib.decompress(zlib_data, zlib.MAX_WBITS|32)

另外，也可以使用gzip来解压缩gzip数据流

import gzip

import StringIO

fio = StringIO.StringIO(gzip_data)

f = gzip.GzipFile(fileobj=fio)

print "51," + f.read()

f.close()

附参考文章地址及原文摘要：

You have this error:

zlib.error:Error-3whiledecompressing:incorrect header check

Which is most likely because you are trying to check headers that are not there, e.g. your data followsRFC 1951 (deflate compressed format) rather thanRFC 1950 (zlib compressed format) orRFC 1952 (gzip compressed format).

choosing windowBits

But zlib can decompress all those formats:

to (de-)compress deflate format, use wbits = -zlib.MAX_WBITS

to (de-)compress zlib format, use wbits = zlib.MAX_WBITS

to (de-)compress gzip format, use wbits = zlib.MAX_WBITS | 16

See documentation in http://www.zlib.net/manual.html#Advanced (sectioninflateInit2)

examples

test data:

>>>deflate_compress=zlib.compressobj(9,zlib.DEFLATED,-zlib.MAX_WBITS)>>>zlib_compress=zlib.compressobj(9,zlib.DEFLATED,zlib.MAX_WBITS)>>>gzip_compress=zlib.compressobj(9,zlib.DEFLATED,zlib.MAX_WBITS|16)>>>>>>text='''test'''>>>deflate_data=deflate_compress.compress(text)+deflate_compress.flush()>>>zlib_data=zlib_compress.compress(text)+zlib_compress.flush()>>>gzip_data=gzip_compress.compress(text)+gzip_compress.flush()>>>

obvious test for zlib:

>>>zlib.decompress(zlib_data)'test'

test for deflate:

>>>zlib.decompress(deflate_data)Traceback(most recent call last):File"",line1,inzlib.error:Error-3whiledecompressing data:incorrect header check>>>zlib.decompress(deflate_data,-zlib.MAX_WBITS)'test'

test for gzip:

>>>zlib.decompress(gzip_data)Traceback(most recent call last):File"",line1,inzlib.error:Error-3whiledecompressing data:incorrect header check>>>zlib.decompress(gzip_data,zlib.MAX_WBITS|16)'test'

the data is also compatible with gzip module:

>>>importgzip>>>importStringIO>>>fio=StringIO.StringIO(gzip_data)>>>f=gzip.GzipFile(fileobj=fio)>>>f.read()'test'>>>f.close()

automatic header detection (zlib or gzip)

adding 32 to windowBits will trigger header detection

>>>zlib.decompress(gzip_data,zlib.MAX_WBITS|32)'test'>>>zlib.decompress(zlib_data,zlib.MAX_WBITS|32)'test'

using gzip instead

or you can ignore zlib and use gzip module directly; butplease remember that under the hood,gzip uses zlib.

fh=gzip.open('abc.gz','rb')cdata=fh.read()fh.close()