First commit (Ch3 chat app).

Chapter3/ChatApp/src/client.nim

@@ -0,0 +1,28 @@
+import os, threadpool, asyncnet, asyncdispatch, protocol
+
+proc connect(socket: AsyncSocket, serverAddr: string) {.async.} =
+ echo("Connecting to ", serverAddr)
+ await socket.connect(serverAddr, 7687.Port)
+ echo("Connected!")
+ while true:
+ let line = await socket.recvLine()
+ let parsed = parseMessage(line)
+ echo(parsed.username, " said ", parsed.message)
+
+echo("Chat application started")
+
+if paramCount() == 0:
+ quit("Please specify the server address")
+
+let serverAddr = paramStr(1)
+var socket = newAsyncSocket()
+
+asyncCheck connect(socket, serverAddr)
+var messageFlowVar = spawn stdin.readLine()
+while true:
+ if messageFlowVar.isReady():
+ let message = createMessage("Anonymous", ^messageFlowVar)
+ asyncCheck socket.send(message)
+ messageFlowVar = spawn stdin.readLine()
+
+ asyncdispatch.poll()

Chapter3/ChatApp/src/protocol.nim

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+import json
+type
+ Message* = object
+ username*: string
+ message*: string
+
+proc parseMessage*(data: string): Message =
+ let dataJson = parseJson(data)
+ result.username = dataJson["username"].getStr()
+ result.message = dataJson["message"].getStr()
+
+proc createMessage*(username, message: string): string =
+ result = $(%{
+ "username": %username,
+ "message": %message
+ }) & "\c\l"
+
+when isMainModule:
+ block:
+ let data = """{"username": "John", "message": "Hi!"}"""
+ let parsed = parseMessage(data)
+ doAssert parsed.username == "John"
+ doAssert parsed.message == "Hi!"
+
+ block:
+ let data = """foobar"""
+ try:
+ let parsed = parseMessage(data)
+ doAssert false
+ except JsonParsingError:
+ doAssert true
+ except:
+ doAssert false
+
+ block:
+ let expected = """{"username":"dom","message":"hello"}""" & "\c\l"
+ doAssert createMessage("dom", "hello") == expected
+
+ echo("All tests passed!")

Chapter3/ChatApp/src/server.nim

@@ -0,0 +1 @@
+import asyncdispatch, asyncnettype Client = ref object socket: AsyncSocket netAddr: string id: int connected: bool Server = ref object socket: AsyncSocket clients: seq[Client]proc newServer(): Server = Server(socket: newAsyncSocket(), clients: @[])proc `$`(client: Client): string = $client.id & "(" & client.netAddr & ")"proc processMessages(server: Server, client: Client) {.async.} = while true: let line = await client.socket.recvLine() if line.len == 0: echo(client, " disconnected!") client.connected = false client.socket.close() return echo(client, " sent: ", line)proc loop(server: Server, port = 7687) {.async.} = server.socket.bindAddr(port.Port) server.socket.listen() while true: let (netAddr, clientSocket) = await server.socket.acceptAddr() echo("Accepted connection from ", netAddr) let client = Client( socket: clientSocket, netAddr: netAddr, id: server.clients.len, connected: true ) server.clients.add(client) asyncCheck processMessages(server, client)var server = newServer()waitFor loop(server)