Files
Nim/tests/niminaction/Chapter3/ChatApp/src/client.nim
2017-10-01 17:17:40 +01:00

55 lines
2.2 KiB
Nim

import os, threadpool, asyncdispatch, asyncnet
import protocol
proc connect(socket: AsyncSocket, serverAddr: string) {.async.} =
## Connects the specified AsyncSocket to the specified address.
## Then receives messages from the server continuously.
echo("Connecting to ", serverAddr)
# Pause the execution of this procedure until the socket connects to
# the specified server.
await socket.connect(serverAddr, 7687.Port)
echo("Connected!")
while true:
# Pause the execution of this procedure until a new message is received
# from the server.
let line = await socket.recvLine()
# Parse the received message using ``parseMessage`` defined in the
# protocol module.
let parsed = parseMessage(line)
# Display the message to the user.
echo(parsed.username, " said ", parsed.message)
echo("Chat application started")
# Ensure that the correct amount of command line arguments was specified.
if paramCount() < 2:
# Terminate the client early with an error message if there was not
# enough command line arguments specified by the user.
quit("Please specify the server address, e.g. ./client localhost username")
# Retrieve the first command line argument.
let serverAddr = paramStr(1)
# Retrieve the second command line argument.
let username = paramStr(2)
# Initialise a new asynchronous socket.
var socket = newAsyncSocket()
# Execute the ``connect`` procedure in the background asynchronously.
asyncCheck connect(socket, serverAddr)
# Execute the ``readInput`` procedure in the background in a new thread.
var messageFlowVar = spawn stdin.readLine()
while true:
# Check if the ``readInput`` procedure returned a new line of input.
if messageFlowVar.isReady():
# If a new line of input was returned, we can safely retrieve it
# without blocking.
# The ``createMessage`` is then used to create a message based on the
# line of input. The message is then sent in the background asynchronously.
asyncCheck socket.send(createMessage(username, ^messageFlowVar))
# Execute the ``readInput`` procedure again, in the background in a
# new thread.
messageFlowVar = spawn stdin.readLine()
# Execute the asyncdispatch event loop, to continue the execution of
# asynchronous procedures.
asyncdispatch.poll()