source: binary-improvements/MapRendering/Web/Handlers/SessionHandler.cs@ 382

using System.IO;
using System.Net;
using System.Text;

namespace AllocsFixes.NetConnections.Servers.Web.Handlers {
        public class SessionHandler : PathHandler {
                private readonly string footer = "";
                private readonly string header = "";

                public SessionHandler (string _dataFolder, string _moduleName = null) : base (_moduleName) {
                        if (File.Exists (_dataFolder + "/sessionheader.tmpl")) {
                                header = File.ReadAllText (_dataFolder + "/sessionheader.tmpl");
                        }

                        if (File.Exists (_dataFolder + "/sessionfooter.tmpl")) {
                                footer = File.ReadAllText (_dataFolder + "/sessionfooter.tmpl");
                        }
                }

                public override void HandleRequest (HttpListenerRequest _req, HttpListenerResponse _resp, WebConnection _user,
                        int _permissionLevel) {
                        string subpath = _req.Url.AbsolutePath.Remove (0, urlBasePath.Length);

                        StringBuilder result = new StringBuilder ();
                        result.Append (header);

                        if (subpath.StartsWith ("verify")) {
                                if (_user != null) {
                                        _resp.Redirect ("/static/index.html");
                                        return;
                                }

                                result.Append (
                                        "<h1>Login failed, <a href=\"/static/index.html\">click to return to main page</a>.</h1>");
                        } else if (subpath.StartsWith ("logout")) {
                                if (_user != null) {
                                        parent.connectionHandler.LogOut (_user.SessionID);
                                        Cookie cookie = new Cookie ("sid", "", "/");
                                        cookie.Expired = true;
                                        _resp.AppendCookie (cookie);
                                        _resp.Redirect ("/static/index.html");
                                        return;
                                }

                                result.Append (
                                        "<h1>Not logged in, <a href=\"/static/index.html\">click to return to main page</a>.</h1>");
                        } else if (subpath.StartsWith ("login")) {
                                string host = (Web.IsSslRedirected (_req) ? "https://" : "http://") + _req.UserHostName;
                                string url = OpenID.GetOpenIdLoginUrl (host, host + "/session/verify");
                                _resp.Redirect (url);
                                return;
                        } else {
                                result.Append (
                                        "<h1>Unknown command, <a href=\"/static/index.html\">click to return to main page</a>.</h1>");
                        }

                        result.Append (footer);

                        _resp.ContentType = MimeType.GetMimeType (".html");
                        _resp.ContentEncoding = Encoding.UTF8;
                        byte[] buf = Encoding.UTF8.GetBytes (result.ToString ());
                        _resp.ContentLength64 = buf.Length;
                        _resp.OutputStream.Write (buf, 0, buf.Length);
                }
        }
}