flask_utils.py

#!/usr/bin/env python3

# Copyright (C) 2012-2015  ASTRON (Netherlands Institute for Radio Astronomy)
# P.O. Box 2, 7990 AA Dwingeloo, The Netherlands
#
# This file is part of the LOFAR software suite.
# The LOFAR software suite is free software: you can redistribute it and/or
# modify it under the terms of the GNU General Public License as published
# by the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# The LOFAR software suite is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with the LOFAR software suite. If not, see <http://www.gnu.org/licenses/>.

# $Id$

from flask import after_this_request, request
from io import BytesIO as IO
import gzip
import functools
from datetime import datetime

def gzipped(f):
    @functools.wraps(f)
    def view_func(*args, **kwargs):
        @after_this_request
        def zipper(response):
            accept_encoding = request.headers.get('Accept-Encoding', '')

            if 'gzip' not in accept_encoding.lower():
                return response

            response.direct_passthrough = False

            if (response.status_code < 200 or
                response.status_code >= 300 or
                'Content-Encoding' in response.headers):
                return response
            gzip_buffer = IO()
            gzip_file = gzip.GzipFile(mode='wb',
                                      fileobj=gzip_buffer)
            gzip_file.write(response.data)
            gzip_file.close()

            response.data = gzip_buffer.getvalue()
            response.headers['Content-Encoding'] = 'gzip'
            response.headers['Vary'] = 'Accept-Encoding'
            response.headers['Content-Length'] = len(response.data)

            return response

        return f(*args, **kwargs)

    return view_func