python - 来自 Python websocket 的 Django 通道上的数据渲染
问题描述
我正在尝试将数据从我的 python websocket 客户端发送到 Django Channels 服务器。
我正在使用python web socket 客户端。
我的 websocket.py
def on_message(ws, message):
print (message)
def on_error(ws, error):
print ("eroror:", error)
def on_close(ws):
print ("### closed ###")
# Attemp to reconnect with 2 seconds interval
time.sleep(2)
initiate()
def on_open(ws):
print ("### Initiating new websocket connectipython my-websocket.pyon ###")
def run(*args):
for i in range(30000):
# Sending message with 1 second intervall
time.sleep(1)
ws.send("Hello %d" % i)
# ws.send(json.dumps("Hello %d" % i))
time.sleep(1)
ws.close()
print ("thread terminating...")
_thread.start_new_thread(run, ())
def initiate():
websocket.enableTrace(True)
ws = websocket.WebSocketApp("ws://localhost:8000/ws/power/room/",
on_message = on_message,
on_error = on_error,
on_close = on_close)
ws.on_open = on_open
ws.run_forever()
if __name__ == "__main__":
initiate()
我的 Django Channels 消费者是
消费者.py
class EchoConsumer(WebsocketConsumer):
def connect(self):
self.room_name = self.scope['url_route']['kwargs']['room_name']
self.room_group_name = 'power_%s' % self.room_name
# Join room group
async_to_sync(self.channel_layer.group_add)(
self.room_group_name,
self.channel_name
)
self.accept()
def disconnect(self, close_code):
# Leave room group
async_to_sync(self.channel_layer.group_discard)(
self.room_group_name,
self.channel_name
)
# Receive message from WebSocket
def receive(self, text_data):
text_data_json = json.loads(text_data)
message = text_data_json['message']
# Send message to room group
async_to_sync(self.channel_layer.group_send)(
self.room_group_name,
{
'type': 'chat_message',
'message': message
}
)
# Receive message from room group
def chat_message(self, event):
message = event['message']
# Send message to WebSocket
self.send(text_data=json.dumps({
'message': message
}))
错误
WebSocket HANDSHAKING /ws/power/room/ [127.0.0.1:54591]
WebSocket CONNECT /ws/power/room/ [127.0.0.1:54591]
Exception inside application: Expecting value: line 1 column 1 (char 0)
File "C:\Program Files\Python37\lib\site-packages\channels\sessions.py", line 179, in __call__
return await self.inner(receive, self.send)
File "C:\Program Files\Python37\lib\site-packages\channels\middleware.py", line 41, in coroutine_call
await inner_instance(receive, send)
File "C:\Program Files\Python37\lib\site-packages\channels\consumer.py", line 59, in __call__
[receive, self.channel_receive], self.dispatch
File "C:\Program Files\Python37\lib\site-packages\channels\utils.py", line 52, in await_many_dispatch
await dispatch(result)
File "C:\Program Files\Python37\lib\site-packages\asgiref\sync.py", line 108, in __call__
return await asyncio.wait_for(future, timeout=None)
File "C:\Program Files\Python37\lib\asyncio\tasks.py", line 388, in wait_for
return await fut
File "C:\Program Files\Python37\lib\concurrent\futures\thread.py", line 57, in run
result = self.fn(*self.args, **self.kwargs)
File "C:\Program Files\Python37\lib\site-packages\channels\db.py", line 13, in thread_handler
return super().thread_handler(loop, *args, **kwargs)
File "C:\Program Files\Python37\lib\site-packages\asgiref\sync.py", line 123, in thread_handler
return self.func(*args, **kwargs)
File "C:\Program Files\Python37\lib\site-packages\channels\consumer.py", line 105, in dispatch
handler(message)
File "C:\Program Files\Python37\lib\site-packages\channels\generic\websocket.py", line 60, in websocket_receive
self.receive(text_data=message["text"])
File "C:\Users\Suleman\PycharmProjects\power\myChannels\consumers.py", line 41, in receive
text_data_json = json.loads(text_data)
File "C:\Program Files\Python37\lib\json\__init__.py", line 348, in loads
return _default_decoder.decode(s)
File "C:\Program Files\Python37\lib\json\decoder.py", line 337, in decode
obj, end = self.raw_decode(s, idx=_w(s, 0).end())
File "C:\Program Files\Python37\lib\json\decoder.py", line 355, in raw_decode
raise JSONDecodeError("Expecting value", s, err.value) from None
Expecting value: line 1 column 1 (char 0)
WebSocket DISCONNECT /ws/power/room/ [127.0.0.1:54591]
从错误中可以看出,我可以在 websocket 之间进行握手,但数据未在网页上呈现。
解决方案
仔细查看日志,似乎 websocket 已连接:
WebSocket CONNECT /ws/power/room/ [127.0.0.1:54591]
但是消费者receive
方法引发了一个 JSON 异常,当然是因为它的参数text_data
是None
.
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