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# This file is part of the Neurorobotics Platform software
# Copyright (C) 2014,2015,2016,2017 Human Brain Project
# https://www.humanbrainproject.eu
#
# The Human Brain Project is a European Commission funded project
# in the frame of the Horizon2020 FET Flagship plan.
# http://ec.europa.eu/programmes/horizon2020/en/h2020-section/fet-flagships
#
# This program 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 2
# of the License, or (at your option) any later version.
#
# This program 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 this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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"""
This module makes some rest requests multi-threadable.
By default, all rest requests are considered not thread safe and are therefore synchronized.
Requests that are known to be thread-safe, are executed concurrently.
To mark a rest request as thread-safe, decorate the Resource function handling the request
(get, post, delete, put) with the decorator @RestSyncMiddleware.threadsafe
"""
from builtins import object
from threading import Lock
import logging
from werkzeug.exceptions import NotFound
logger = logging.getLogger(__name__)
[docs]class RestSyncMiddleware(object):
"""
Middleware that allows thread-safe requests to be executed concurrently
"""
def __init__(self, wsgi_app, app):
self.wsgi_app = wsgi_app
self.app = app
self.threadLock = Lock()
[docs] @staticmethod
def threadsafe(func):
"""
Decorates functions as thread-safe
"""
func.is_threadsafe = True
return func
def __call__(self, environ, start_response):
pathinfo = environ.get("PATH_INFO")
method = environ.get("REQUEST_METHOD")
try:
viewfunction, _ = self.app.url_map.bind(
'localhost', default_method=method).match(pathinfo)
except NotFound:
return self.wsgi_app(environ, start_response)
try:
viewclass = self.app.view_functions[viewfunction].view_class
except AttributeError:
return self.wsgi_app(environ, start_response)
viewfn = getattr(viewclass, method.lower())
if not hasattr(viewfn, "is_threadsafe"):
self.threadLock.acquire()
try:
res = self.wsgi_app(environ, start_response)
# pylint: disable=broad-except
except Exception as e:
logger.exception(e)
res = None
finally:
if not hasattr(viewfn, "is_threadsafe"):
self.threadLock.release()
return res