Coding/BinaryDad.Coding/Hubs/CodeHub.cs

using Microsoft.AspNetCore.SignalR;
using System;
using System.Threading.Tasks;

namespace BinaryDad.Coding.Hubs
{
    public class CodeHub : Hub
    {
        public Task UpdateCode(string user, int index, string code, bool isTeacher)
        {
            if (index == 0)
            {
                if (Users.Sessions.TryGetValue(Context.ConnectionId, out User value))
                {
                    value.Html = code;
                }
            }
            else if (index == 1)
            {
                if (Users.Sessions.TryGetValue(Context.ConnectionId, out User value))
                {
                    value.Css = code;
                }
            }

            // only send to all if it's a teacher
            if (isTeacher)
            {
                return Clients.All.SendAsync("ReceiveCode", user, index, code);
            }

            return null;
        }

        public async Task SaveName(string name, string color)
        {
            if (!Users.Sessions.ContainsKey(Context.ConnectionId))
            {
                Users.Sessions[Context.ConnectionId].Id = Context.ConnectionId;
                Users.Sessions[Context.ConnectionId].Name = name;
                Users.Sessions[Context.ConnectionId].Color = string.IsNullOrWhiteSpace(color) ? "white" : color;
            }

            await Clients.All.SendAsync("UsersList", Users.Sessions);
        }

        public override async Task OnConnectedAsync()
        {
            Users.Sessions[Context.ConnectionId] = new User
            {
                Name = string.Empty
            };

            await Clients.All.SendAsync("UsersList", Users.Sessions);

            await base.OnConnectedAsync();
        }

        public override async Task OnDisconnectedAsync(Exception exception)
        {
            if (Users.Sessions.ContainsKey(Context.ConnectionId))
            {
                Users.Sessions.Remove(Context.ConnectionId);
            }

            await Clients.All.SendAsync("UsersList", Users.Sessions);

            await base.OnDisconnectedAsync(exception);
        }
    }
}