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from collections import namedtuple
from flask import Response
from flask import request
from functools import wraps
from geventwebsocket.handler import WebSocketHandler
import inspect
import logging
from socketio import socketio_manage
from socketio.server import SocketIOHandler
from socketio.server import SocketIOServer
from model.graph import Attr_Diff, Topo_Diff
from rz_api_websocket import WebSocket_Graph_NS
from rz_kernel import RZ_Kernel
from rz_req_handling import make_response__http__empty
log = logging.getLogger('rhizi')
class RZ_WebSocket_Server(SocketIOServer):
"""
Rhizi customized SocketIOServer:
- allow response header injection on websocket connections
"""
class WebSocketHandlerExt(SocketIOHandler):
def start_response(self, status, headers, exc_info=None):
headers['Access-Control-Allow-Origin'] = '*'
return WebSocketHandler.start_response(self, status, headers, exc_info)
def handle_one_response(self):
return WebSocketHandler.handle_one_response(self)
def upgrade_websocket(self):
return WebSocketHandler.upgrade_websocket(self)
def __init__ (self, cfg, wsgi_app):
self.wsgi_app = wsgi_app
# Thread.__init__(self)
SocketIOServer.__init__(self,
(cfg.listen_address, cfg.listen_port),
wsgi_app,
resource='socket.io',
policy_server=False)
def log_multicast(self, msg_name):
multicast_size = len(self.sockets) - 1 # subtract self socket
log.info('ws: multicast: msg: \'%s\', cast-size ~= %d' % (msg_name, multicast_size)) # ~=: as race conditions apply
def init_ws_interface(cfg, kernel, flask_webapp):
"""
Initialize websocket interface:
- apply websocket route handlers
@return: an initialized RZ_WebSocket_Server object
"""
# init websocket-env
ws_env = namedtuple('RZ_websocket_env', ['kernel'])
ws_env.kernel = kernel
def socketio_route_handler(url_path):
try:
if None == request.environ.get('socketio'):
# avoid python-socketio's direct access to environ['socketio']
raise Exception('failed to obtain socketio object from WSGI environment')
# connect socketio manager
socketio_manage(request.environ, {'/graph': WebSocket_Graph_NS}, ws_env)
except:
flask_webapp.logger.error("Exception while handling socketio connection", exc_info=True)
return make_response__http__empty(101) # 'switching protocols' HTTP status code
def ws_broadcast_to_all(pkt):
for sessid, socket in ws_srv.sockets.iteritems():
socket.send_packet(pkt)
# link ws hooks: multicast on topo_diff, attr_diff
def decorator__ws_multicast(ws_srv, f, f_multicast):
"""
@param f: [!] wrapped function, name used to derive socket message name
"""
def _prep_for_serialization(obj):
# handle special serialization cases
if isinstance(obj, Topo_Diff):
return obj.to_json_dict()
return obj
@wraps(f)
def wrapped_function(*args, **kw):
f_ret = f(*args, **kw)
try:
# TODO: avoid stack inspection if possible
stack = inspect.stack()
stack_frame = stack[1][0]
obj_instance = stack_frame.f_locals.get('self')
if None != obj_instance:
# [!] no need emit broadcast if call originated from a websocket as
# WebSocket_Graph_NS#on_diff_commit__xxx emit their own self-excluding multicast
# we still asser call class == WebSocket_Graph_NS
caller_class = obj_instance.__class__
assert WebSocket_Graph_NS == caller_class, 'decorator__ws_multicast: unknown callpath: not from WebSocket_Graph_NS'
return f_ret
except Exception as e:
log.exception('decorator__ws_multicast: failed to detect REST/Websocket call via stack inspection') # exception derived from stack
assert type(f_ret) in [list, tuple]
pkt_data = map(_prep_for_serialization, f_ret)
msg_name = f.__name__
pkt = dict(type="event",
name=msg_name,
args=pkt_data,
endpoint='/graph')
ws_srv.log_multicast(msg_name)
ws_broadcast_to_all(pkt)
return f_ret
return wrapped_function
# connect socketio route
route_dec = flask_webapp.route('/socket.io/<path:url_path>')
f = route_dec(socketio_route_handler)
flask_webapp.f = f
# init ws server
ws_srv = RZ_WebSocket_Server(cfg, flask_webapp)
kernel.diff_commit__topo = decorator__ws_multicast(ws_srv,
kernel.diff_commit__topo,
f_multicast=WebSocket_Graph_NS.on_diff_commit__topo)
kernel.diff_commit__attr = decorator__ws_multicast(ws_srv,
kernel.diff_commit__attr,
f_multicast=WebSocket_Graph_NS.on_diff_commit__attr)
return ws_srv;
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