Python websockets send to client and keep connection alive
I'm using python websockets: https://websockets.readthedocs.io/
They have a simple client/server example, where the server echoes the client's input back once. The code looks like this:
Client side:
# WS client example
import asyncio
import websockets
async def hello():
async with websockets.connect(
'ws://localhost:8765') as websocket:
name = input("What's your name? ")
await websocket.send(name)
print(f"> {name}")
greeting = await websocket.recv()
print(f"< {greeting}")
asyncio.get_event_loop().run_until_complete(hello())
Server side:
# WS server example
import asyncio
import websockets
async def hello(websocket, path):
name = await websocket.recv()
print(f"< {name}")
greeting = f"Hello {name}!"
await websocket.send(greeting)
print(f"> {greeting}")
start_server = websockets.serve(hello, 'localhost', 8765)
asyncio.get_event_loop().run_until_complete(start_server)
asyncio.get_event_loop().run_forever()
I want to adapt just the server side only, so that it does the following upon a socket connection:
- Send an acknowledgement message to the client. e.g.
Hello Client! Please wait for your data.
- Keep the connection alive.
- Process some data that takes some time.
- After the data has completed processing, notify the client on the existing websocket connection. e.g.
Your data is here!
The python websockets documentation doesn't have a code sample which does this.
python websocket python-asyncio
asked Nov 16 '18 at 3:46
AntonAnton
852718
add a comment |
I'm using python websockets: https://websockets.readthedocs.io/
They have a simple client/server example, where the server echoes the client's input back once. The code looks like this:
Client side:
# WS client example
import asyncio
import websockets
async def hello():
async with websockets.connect(
'ws://localhost:8765') as websocket:
name = input("What's your name? ")
await websocket.send(name)
print(f"> {name}")
greeting = await websocket.recv()
print(f"< {greeting}")
asyncio.get_event_loop().run_until_complete(hello())
Server side:
# WS server example
import asyncio
import websockets
async def hello(websocket, path):
name = await websocket.recv()
print(f"< {name}")
greeting = f"Hello {name}!"
await websocket.send(greeting)
print(f"> {greeting}")
start_server = websockets.serve(hello, 'localhost', 8765)
asyncio.get_event_loop().run_until_complete(start_server)
asyncio.get_event_loop().run_forever()
I want to adapt just the server side only, so that it does the following upon a socket connection:
- Send an acknowledgement message to the client. e.g.
Hello Client! Please wait for your data.
- Keep the connection alive.
- Process some data that takes some time.
- After the data has completed processing, notify the client on the existing websocket connection. e.g.
Your data is here!
The python websockets documentation doesn't have a code sample which does this.
python websocket python-asyncio
asked Nov 16 '18 at 3:46
AntonAnton
852718
add a comment |
I'm using python websockets: https://websockets.readthedocs.io/
They have a simple client/server example, where the server echoes the client's input back once. The code looks like this:
Client side:
# WS client example
import asyncio
import websockets
async def hello():
async with websockets.connect(
'ws://localhost:8765') as websocket:
name = input("What's your name? ")
await websocket.send(name)
print(f"> {name}")
greeting = await websocket.recv()
print(f"< {greeting}")
asyncio.get_event_loop().run_until_complete(hello())
Server side:
# WS server example
import asyncio
import websockets
async def hello(websocket, path):
name = await websocket.recv()
print(f"< {name}")
greeting = f"Hello {name}!"
await websocket.send(greeting)
print(f"> {greeting}")
start_server = websockets.serve(hello, 'localhost', 8765)
asyncio.get_event_loop().run_until_complete(start_server)
asyncio.get_event_loop().run_forever()
I want to adapt just the server side only, so that it does the following upon a socket connection:
- Send an acknowledgement message to the client. e.g.
Hello Client! Please wait for your data.
- Keep the connection alive.
- Process some data that takes some time.
- After the data has completed processing, notify the client on the existing websocket connection. e.g.
Your data is here!
The python websockets documentation doesn't have a code sample which does this.
python websocket python-asyncio
asked Nov 16 '18 at 3:46
AntonAnton
852718
I'm using python websockets: https://websockets.readthedocs.io/
They have a simple client/server example, where the server echoes the client's input back once. The code looks like this:
Client side:
# WS client example
import asyncio
import websockets
async def hello():
async with websockets.connect(
'ws://localhost:8765') as websocket:
name = input("What's your name? ")
await websocket.send(name)
print(f"> {name}")
greeting = await websocket.recv()
print(f"< {greeting}")
asyncio.get_event_loop().run_until_complete(hello())
Server side:
# WS server example
import asyncio
import websockets
async def hello(websocket, path):
name = await websocket.recv()
print(f"< {name}")
greeting = f"Hello {name}!"
await websocket.send(greeting)
print(f"> {greeting}")
start_server = websockets.serve(hello, 'localhost', 8765)
asyncio.get_event_loop().run_until_complete(start_server)
asyncio.get_event_loop().run_forever()
I want to adapt just the server side only, so that it does the following upon a socket connection:
- Send an acknowledgement message to the client. e.g.
Hello Client! Please wait for your data.
- Keep the connection alive.
- Process some data that takes some time.
- After the data has completed processing, notify the client on the existing websocket connection. e.g.
Your data is here!
The python websockets documentation doesn't have a code sample which does this.
python websocket python-asyncio
python websocket python-asyncio
asked Nov 16 '18 at 3:46
AntonAnton
852718
asked Nov 16 '18 at 3:46
AntonAnton
852718
asked Nov 16 '18 at 3:46
AntonAnton
852718
asked Nov 16 '18 at 3:46
AntonAnton
852718
asked Nov 16 '18 at 3:46
AntonAnton
852718
852718
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
Presumably your function that processes the data is blocking, otherwise you'd simply await it inside the coroutine. The straightforward approach is to use run_in_executor to run it in another thread, and await it in your handler coroutine:
async def hello(websocket, path):
loop = asyncio.get_event_loop()
await websocket.send("Hello Client! Please wait for your data.")
data = await loop.run_in_executor(None, get_data)
await websocket.send("Your data is here!")
await websocket.send(data)
def get_data():
# something that takes a long time to calculate
x = 19134702400093278081449423917**300000 % 256
return bytes([x])
answered Nov 16 '18 at 9:57
user4815162342user4815162342
64.1k594151
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
Presumably your function that processes the data is blocking, otherwise you'd simply await it inside the coroutine. The straightforward approach is to use run_in_executor to run it in another thread, and await it in your handler coroutine:
async def hello(websocket, path):
loop = asyncio.get_event_loop()
await websocket.send("Hello Client! Please wait for your data.")
data = await loop.run_in_executor(None, get_data)
await websocket.send("Your data is here!")
await websocket.send(data)
def get_data():
# something that takes a long time to calculate
x = 19134702400093278081449423917**300000 % 256
return bytes([x])
answered Nov 16 '18 at 9:57
user4815162342user4815162342
64.1k594151
add a comment |
Presumably your function that processes the data is blocking, otherwise you'd simply await it inside the coroutine. The straightforward approach is to use run_in_executor to run it in another thread, and await it in your handler coroutine:
async def hello(websocket, path):
loop = asyncio.get_event_loop()
await websocket.send("Hello Client! Please wait for your data.")
data = await loop.run_in_executor(None, get_data)
await websocket.send("Your data is here!")
await websocket.send(data)
def get_data():
# something that takes a long time to calculate
x = 19134702400093278081449423917**300000 % 256
return bytes([x])
answered Nov 16 '18 at 9:57
user4815162342user4815162342
64.1k594151
add a comment |
Presumably your function that processes the data is blocking, otherwise you'd simply await it inside the coroutine. The straightforward approach is to use run_in_executor to run it in another thread, and await it in your handler coroutine:
async def hello(websocket, path):
loop = asyncio.get_event_loop()
await websocket.send("Hello Client! Please wait for your data.")
data = await loop.run_in_executor(None, get_data)
await websocket.send("Your data is here!")
await websocket.send(data)
def get_data():
# something that takes a long time to calculate
x = 19134702400093278081449423917**300000 % 256
return bytes([x])
answered Nov 16 '18 at 9:57
user4815162342user4815162342
64.1k594151
Presumably your function that processes the data is blocking, otherwise you'd simply await it inside the coroutine. The straightforward approach is to use run_in_executor to run it in another thread, and await it in your handler coroutine:
async def hello(websocket, path):
loop = asyncio.get_event_loop()
await websocket.send("Hello Client! Please wait for your data.")
data = await loop.run_in_executor(None, get_data)
await websocket.send("Your data is here!")
await websocket.send(data)
def get_data():
# something that takes a long time to calculate
x = 19134702400093278081449423917**300000 % 256
return bytes([x])
answered Nov 16 '18 at 9:57
user4815162342user4815162342
64.1k594151
edited Nov 16 '18 at 12:01
answered Nov 16 '18 at 9:57
user4815162342user4815162342
64.1k594151
answered Nov 16 '18 at 9:57
user4815162342user4815162342
64.1k594151
answered Nov 16 '18 at 9:57
user4815162342user4815162342
64.1k594151
64.1k594151
add a comment |
add a comment |
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