Question

I had expected this to work:

>>> import urllib.request as r
>>> import zlib
>>> r.urlopen( r.Request("http://google.com/search?q=foo", headers={"User-Agent": "Mozilla/5.0 (X11; U; Linux i686) Gecko/20071127 Firefox/2.0.0.11", "Accept-Encoding": "gzip"}) ).read()
b'af0\r\n\x1f\x8b\x08...(long binary string)'
>>> zlib.decompress(_)
Traceback (most recent call last):
  File "<pyshell#87>", line 1, in <module>
    zlib.decompress(x)
zlib.error: Error -3 while decompressing data: incorrect header check

But it doesn’t. Dive Into Python uses StringIO in this example, but that seems to be missing from Python 3. What’s the right way of doing it?

Answer 1

It works fine with gzip (gzip and zlib are the same compression but with different headers/”wrapping”. Your error has this information in the message).

import gzip
import urllib.request

request = urllib.request.Request(
    "http://google.com/search?q=foo",
    headers={
        "Accept-Encoding": "gzip",
        "User-Agent": "Mozilla/5.0 (X11; U; Linux i686) Gecko/20071127 Firefox/2.0.0.11", 
    })
response = urllib.request.urlopen(request)
gzipFile = gzip.GzipFile(fileobj=response)
gzipFile.read()