Implement support for gzip Content-Encoding in HTTP requests

[vkuznet]

Impact of the new feature
Currently, our HTTP clients (WMCore and elsewhere) do not use gzip encoding neither when they send or request data from DBS. Due to increasing size of our data in DBS, e.g. bulkblock API can post 180MB in one call, it is desired to use gzip Content-Encoding which can reduce this size by factor of 25 !!!

Is your feature request related to a problem? Please describe.
Not necessary, but it is desired to add such support to reduce HTTP request time and network bandwidth

Describe the solution you'd like
Here is a fully working example how to achieve gzip encoding with HTTP request with CherryPy server:

#!/usr/bin/env python
#-*- coding: utf-8 -*-
# CherryPy server to support gzip Encoding
"""
File       : cpy_gzip.py
Author     : Valentin Kuznetsov <vkuznet AT gmail dot com>
Description: CherryPy server for POST gzipped requests
"""

# system modules
import os
import sys
import json
import cherrypy

try:
    import cStringIO as StringIO
except ImportError: # python3
    import io
except:
    import StringIO

def decompress(body):
    import gzip

    if  sys.version.startswith('3.'):
        zbuf = io.BytesIO()
    else:
        zbuf = StringIO.StringIO()
    zbuf.write(body)
    zbuf.seek(0)
    zfile = gzip.GzipFile(mode='rb', fileobj=zbuf)
    data = zfile.read()
    zfile.close()
    return data

class Test(object):
    @cherrypy.expose
    @cherrypy.tools.accept(media='application/json')
    def index(self):
        raw = cherrypy.request.body.read(int(cherrypy.request.headers['Content-Length']))
        if cherrypy.request.headers['Content-Encoding'] == 'gzip':
            raw = decompress(raw)
            return raw
        b = json.loads(raw)
        return json.dumps(b)

if __name__ == '__main__':
    cherrypy.quickstart(Test())

If you can run this code it will provide CherryPy server which supports gzip encoding.

Now, the client only needs to add appropriate gzip HTTP header as follows:

curl -H "Content-Encoding: gzip" -H "Content-type: application/json" --data-binary @/Users/vk/Downloads/bb.json.gz
http://localhost:8080

Describe alternatives you've considered
None

Additional context
New dbs2go support this encoding and clients can take advantage of it, i.e. clients can supply Content-Encoding: gzip and results from dbs2go will be gzip'ed and returned to the client. Of course, client should take care how to unzip them and this can be implemented via decompress function shown above.

[amaltaro]

@vkuznet Valentin, we already have such issue opened, see: #10451
I'm going to make a reference to this issue over there and close this one as duplicate. If I'm wrong, please re-open it.
Thanks for creating it though and providing some extra examples.