How to unzip and read gzipped JSON files from URL in Python

The Problem

Sometimes we end up zipping JSON files and putting up somewhere on the interweb. Now we need to read it back from the HTTP server and parse the file using Python. For that situation, let us assume that the zipped JSON is located at this URL:
http://example.com/python_list_turned_into.json.gz. To read this file, we need to do the following

• Fetch the file using urllib2
• Add a header which will be used to detect the gzip format
• Then open the file and read the compressed file
• Next, uncompress the file using gzip library and load it!

That's it!

The Python Code

Let's look at the code snippet below, which does exactly what we need.

import urllib2
import json
import gzip
import StringIO

def unzipper(url="http://example.com/python_list_turned_into.json.gz"):
    request = urllib2.Request(url)
    request.add_header('Accept-encoding', 'gzip')
    opener = urllib2.build_opener()
    f = opener.open(request)
    compresseddata = f.read()
    compressedstream = StringIO.StringIO(compresseddata)
    gzipper = gzip.GzipFile(fileobj=compressedstream)
    data = gzipper.read()
    list_output = json.loads(data)
    
    return list_output