source: TFP-WebServer/WebServer/src/ConnectionHandler.cs@ 487

using System;
using System.Collections.Generic;
using System.Net;

namespace Webserver {
        public class ConnectionHandler {
                private readonly Dictionary<string, WebConnection> connections = new Dictionary<string, WebConnection> ();

                public WebConnection IsLoggedIn (string _sessionId, IPAddress _ip) {
                        if (!connections.TryGetValue (_sessionId, out WebConnection con)) {
                                return null;
                        }

//                      if (con.Age.TotalMinutes > parent.sessionTimeoutMinutes) {
//                              connections.Remove (_sessionId);
//                              return null;
//                      }

                        // if (!Equals (con.Endpoint, _ip)) { // reverse proxy = same source ip!!
                        //      connections.Remove (_sessionId);
                        //      return null;
                        // }

                        con.UpdateUsage ();

                        return con;
                }

                public void LogOut (string _sessionId) {
                        connections.Remove (_sessionId);
                }

                public WebConnection LogIn (IPAddress _ip, string _username, PlatformUserIdentifierAbs _userId, PlatformUserIdentifierAbs _crossUserId = null) {
                        string sessionId = Guid.NewGuid ().ToString ();
                        WebConnection con = new WebConnection (sessionId, _ip, _username, _userId, _crossUserId);
                        connections.Add (sessionId, con);
                        return con;
                }

                public void SendLine (string _line) {
                        foreach (KeyValuePair<string, WebConnection> kvp in connections) {
                                kvp.Value.SendLine (_line);
                        }
                }
        }
}