如何解决如何在Web套接字中从服务器向客户端发送消息
好吧，我正在做一个小程序，目的是在Rabbitmq上接收消息并发送给连接到具有相同索引的websocket的客户端，但是在发送给客户端时遇到问题，我重用了必须工作的代码在3.6 .9中，我不记得龙卷风的版本（我使用的websocket库），但是我更换了PC，并且能够再次安装它，现在我有了该库和python的最新版本。 / p>
我将发布旧代码，因为它会因为msm错误而更易于理解
import tornado.websocket
import tornado.ioloop
import threading
import pika
import json
def verificar_novo(se):
for i in range(0,len(conexao_lista)):
if se == conexao_lista[i]["endereco"]:
return 0
return 1
def excluir_conexao(endereco):
for i in range(0,len(conexao_lista)):
if conexao_lista[i]["endereco"] == endereco:
del(conexao_lista[i])
break
""" Função para procurar mensagens no rabbit e retornar para os clientes"""
def callback(ch,method,properties,body):
menssagem_rabbit = json.loads(body)
threading.Lock()
for i in range(0,len(conexao_lista)):
if (conexao_lista[i]["configuracao"]["ras_eve_id_indice"]) == (menssagem_rabbit["ras_eve_id_indice"]):
conexao_lista[i]["endereco"].write_message(menssagem_rabbit)
break
threading.RLock()
""" Classe de conexao com cliente"""
class WebSocketHandler(tornado.websocket.WebSocketHandler):
def open(self):
print("Novo cliente conectado")
def on_close(self):
print("Cliente desconectado")
excluir_conexao(self)
def on_message(self,message):
n = verificar_novo(self)
if n == 0:
self.write_message(u"Sua menssagem: " + message)
else:
dados_json = json.loads(message)
conexao_dicionario["endereco"] = self
conexao_dicionario["configuracao"] = dados_json
conexao_lista.append(conexao_dicionario.copy())
self.write_message(u"Usuario conectado " + dados_json["id_usuario"])
def check_origin(self,origin):
return True
"""Função que a thread ficara rodando para consumir as mensagem em segundo plano"""
def procurar_mensagens():
connection = pika.BlockingConnection(pika.ConnectionParameters(host='localhost'))
channel = connection.channel()
channel.basic_consume(queue='testerenan',on_message_callback=callback,auto_ack=True)
channel.start_consuming()
"""Variaveis"""
conexao_lista = []
conexao_dicionario = {"endereco": "","configuracao":""}
"""Chamando a Thread"""
threading.Thread(target=procurar_mensagens,args=()).start()
"""Conexão do WebSocket"""
application = tornado.web.Application([(r"/",WebSocketHandler),])
if __name__ == "__main__":
application.listen(8888)
tornado.ioloop.IOLoop.instance().start()
出现的错误：
Exception in thread Thread-1:
Traceback (most recent call last):
File "/usr/lib/python3.8/threading.py",line 932,in _bootstrap_inner
self.run()
File "/usr/lib/python3.8/threading.py",line 870,in run
self._target(*self._args,**self._kwargs)
File "/home/renan/Área de Trabalho/Projeto-WebSocket/Servidor.py",line 63,in procurar_mensagens
channel.start_consuming()
File "/usr/local/lib/python3.8/dist-packages/pika/adapters/blocking_connection.py",line 1866,in start_consuming
self._process_data_events(time_limit=None)
File "/usr/local/lib/python3.8/dist-packages/pika/adapters/blocking_connection.py",line 2027,in _process_data_events
self.connection.process_data_events(time_limit=time_limit)
File "/usr/local/lib/python3.8/dist-packages/pika/adapters/blocking_connection.py",line 834,in process_data_events
self._dispatch_channel_events()
File "/usr/local/lib/python3.8/dist-packages/pika/adapters/blocking_connection.py",line 566,in _dispatch_channel_events
impl_channel._get_cookie()._dispatch_events()
File "/usr/local/lib/python3.8/dist-packages/pika/adapters/blocking_connection.py",line 1493,in _dispatch_events
consumer_info.on_message_callback(self,evt.method,File "/home/renan/Área de Trabalho/Projeto-WebSocket/Servidor.py",line 26,in callback
conexao_lista[i]["endereco"].write_message(menssagem_rabbit)
File "/home/renan/.local/lib/python3.8/site-packages/tornado/websocket.py",line 342,in write_message
return self.ws_connection.write_message(message,binary=binary)
File "/home/renan/.local/lib/python3.8/site-packages/tornado/websocket.py",line 1098,in write_message
fut = self._write_frame(True,opcode,message,flags=flags)
File "/home/renan/.local/lib/python3.8/site-packages/tornado/websocket.py",line 1075,in _write_frame
return self.stream.write(frame)
File "/home/renan/.local/lib/python3.8/site-packages/tornado/iostream.py",line 555,in write
future = Future() # type: Future[None]
File "/usr/lib/python3.8/asyncio/events.py",line 639,in get_event_loop
raise RuntimeError('There is no current event loop in thread %r.'
RuntimeError: There is no current event loop in thread 'Thread-1'.
如果有人想看看，我将保留该项目供下载： https://github.com/Renan-Sacca/Projeto-WebSocket
解决方法
通常，在混合线程和Tornado时必须非常小心-您不能从其他线程调用大多数Tornado方法（这一直是正确的，但是库在Tornado 5.0中强制执行它更加严格）。特别是，这包括write_message。因此，在callback中，不必调用write_message，而必须要求IOLoop为您调用它。
在主块中，执行global main_io_loop; main_io_loop = IOLoop.current()以保存主线程的IOLoop，以便稍后使用。然后在callback中将对write_message的呼叫替换为
main_io_loop.add_callback(conexao_lista[i]["endereco"].write_message,menssagem_rabbit)
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