How to stop TCP server in Julia? - tcp

Question

TCP example
#async begin
server = listen(2000)
while true
sock = accept(server)
println("Hello World\n")
end
end
To close the connection, you need to call the close method:
close(sock)
How to stop the listener?
close(server) #LoadError: accept: software caused connection abort (ECONNABORTED)

Answer 1

Rather than keep commenting, here's what I think you were probably trying to do:
From the julia REPL:
julia> server = listen(2000)
Base.TCPServer(active)
julia> #async begin
while true
sock = accept(server)
print(readstring(sock))
end
end
From another terminal:
~ $ nc localhost 2000
Hello from the other terminal
[Ctrl-D] % i.e. signal end of file. this closes the connection
In the julia repl, you'll see "Hello from the other terminal" printed as soon as you send the EOF signal, but otherwise the julia prompt will continue as normal. If you repeat this process from the netcat terminal you'll see the message printed in the REPL again, because the socket keeps reactivating inside the while loop.
Ideally if you wanted to shut the whole thing down, you would first close(sock) and then close(server). But, you can't close the socket directly, because it's in the "while" loop and it keeps getting reactivated, and you don't have direct access to the variable "sock".
Therefore you can only close the server, fully expecting an error. So catch it in a try block instead
EDIT: sorry, my bad, the exception relates to the socket, not the server, so you need to wrap that in a try catch block inside your async block instead:
#async begin
while true
try
sock = accept(server)
print(readstring(sock))
catch ex
print("exiting while loop")
break
end
end
end