Enforce username to be unique

Author: Taulim

src/client/public/index.js

@@ -43,6 +43,7 @@ $(function onload() {
 					txtUsername.val('');
 					chatEmpty();
 					chatWriteLine(`You are connected! (${s})`);
+					txtMessage.focus();
 				} else {
 					alert(r);
 					txtUsername.focus();
@@ -128,6 +129,12 @@ $(function onload() {
 		);
 	});
 
+	txtUsername.on('keypress', (e) => {
+		if (e.which === 13) {
+			btnJoin.click();
+		}
+	});
+
 	txtMessage.on('keypress', (e) => {
 		if (e.which === 13) {
 			btnSend.click();

src/server/Configuration.ts

@@ -0,0 +1 @@
+export const UPPERCASE_USERNAMES: boolean = false;

src/server/Connections.ts

@@ -41,6 +41,17 @@ export function FindConnById(pId: string): Promise<Connection | null> {
 	});
 }
 
+export function FindConnByName(pName: string): Promise<Connection | null> {
+	return new Promise((resolve) => {
+		for (const [_Id, _Conn] of Connections.entries()) {
+			if (_Conn.name.toUpperCase() === pName.toUpperCase()) {
+				return resolve(_Conn);
+			}
+		}
+		resolve(null);
+	});
+}
+
 export function RemoveConnById(pId: string): Promise<Boolean> {
 	return new Promise((resolve) => {
 		const deleted = Connections.delete(pId);

src/server/WebSocket.ts

@@ -10,8 +10,11 @@ import {
 	RemoveConnById,
 	CheckConnById,
 	ConnInfo,
+	FindConnByName,
 } from './Connections.ts';
 
+import { UPPERCASE_USERNAMES } from './Configuration.ts';
+
 /**
  * h: Handler
  * s: Sender
@@ -40,14 +43,21 @@ export async function HandleWSConn(pWebSocket: WebSocket): Promise<void> {
 				const objEvent: WSMessage = JSON.parse(event);
 				switch (objEvent.h) {
 					case 'join': {
-						const _name = objEvent.d;
-						if (/^[a-zA-Z0-9]+$/i.test(_name)) {
+						const _name = UPPERCASE_USERNAMES
+							? objEvent.d.toUpperCase()
+							: objEvent.d;
+						if (!/^[a-zA-Z0-9]+$/i.test(_name)) {
+							await RespondJoin(_connInfo, 'Invalid username');
+						} else if (await FindConnByName(_name)) {
+							await RespondJoin(
+								_connInfo,
+								'Username already in use'
+							);
+						} else {
 							_conn.state = true;
-							_conn.name = objEvent.d;
+							_conn.name = _name;
 							await BroadcastJoin(_connInfo);
 							await RespondJoin(_connInfo, 'OK');
-						} else {
-							await RespondJoin(_connInfo, 'Invalid username');
 						}
 						break;
 					}