HTTP method override middleware for Werkzeug

middleware.py

from werkzeug import url_decode

class HTTPMethodOverrideMiddleware(object):
    
    def __init__(self, app):
        self.app = app

    def __call__(self, environ, start_response):
        if 'METHOD_OVERRIDE' in environ.get('QUERY_STRING', ''):
            args = url_decode(environ['QUERY_STRING'])
            method = args.get('__METHOD_OVERRIDE__')
            if method in ['GET', 'POST', 'PUT', 'DELETE']:
                method = method.encode('ascii', 'replace')
                environ['REQUEST_METHOD'] = method
        return self.app(environ, start_response)