Does python urllib2 automatically uncompress gzip data fetched from webpage?

Question

I'm using

 data=urllib2.urlopen(url).read()

I want to know:

1. How can I tell if the data at a URL is gzipped?

2. Does urllib2 automatically uncompress the data if it is gzipped? Will the data always be a string?

Answer 1

1. How can I tell if the data at a URL is gzipped?

This checks if the content is gzipped and decompresses it:

from StringIO import StringIO
import gzip

request = urllib2.Request('http://example.com/')
request.add_header('Accept-encoding', 'gzip')
response = urllib2.urlopen(request)
if response.info().get('Content-Encoding') == 'gzip':
    buf = StringIO(response.read())
    f = gzip.GzipFile(fileobj=buf)
    data = f.read()

2. Does urllib2 automatically uncompress the data if it is gzipped? Will the data always be a string?

No. The urllib2 doesn't automatically uncompress the data because the 'Accept-Encoding' header is not set by the urllib2 but by you using: request.add_header('Accept-Encoding','gzip, deflate')