public void OnException(ExceptionContext context)
        {
            // log the exception
            _logger.LogError(0, context.Exception.GetBaseException(), "Exception occurred.");

            var             ip       = _httpContextAccessor.HttpContext.Connection.RemoteIpAddress.ToString();
            var             path     = context.HttpContext.Request.Path;
            var             userTask = _userManager.GetUser(_signInManager);
            ApplicationUser user     = null;

            try
            {
                userTask.Wait();
                user = userTask.Result;
            }
            catch { }

            var exception = new SiteException
            {
                BookingId  = _shoppingCartRepository.GetSessionCartId(),
                Date       = _calendar.LocalTime(),
                Error      = context.Exception.Message,
                Ip         = ip,
                Path       = path.HasValue ? path.Value : "",
                User       = user,
                StuckTrace = context.Exception.StackTrace
            };

            _appDbContext.Exceptions.Add(exception);
            _appDbContext.SaveChanges();
        }
        public void ProcessRequest(HttpContext context)
        {
            var request  = context.Request;
            var response = context.Response;

            // Accepting user request
            var idStr = request.QueryString["id"];

            try
            {
                int id;
                if (!int.TryParse(idStr, out id))
                {
                    InvalidRequest(context, "Invalid request!");
                    return;
                }
                UploadedFile uploadedFile;
                using (var db = new UploadDb())
                {
                    db.Configuration.AutoDetectChangesEnabled = false;
                    db.Configuration.ProxyCreationEnabled     = false;

                    var file = db.Files.FirstOrDefault(a => a.UploadedFileID == id);
                    if (file == null)
                    {
                        InvalidRequest(context, "File does not exists!");
                        response.StatusCode = 404;
                        return;
                    }
                    uploadedFile = file;
                }

                //SiteException.LogException(new Exception(
                //	string.Format("UploadedFileID:{0}, IsPublic:{1}, UploadDate:{2}, Filename:{3}",
                //		uploadedFile.UploadedFileID,
                //		uploadedFile.IsPublic,
                //		uploadedFile.UploadDate,
                //		uploadedFile.Filename)));

                if (uploadedFile.IsPublic == false)
                {
                    // check the owner
                    var user = UserManager.GetUser();
                    if (user == null)
                    {
                        var succeed = UserManager.BasicAuthorize(context);
                        if (!succeed)
                        {
                            return;
                        }
                        user = UserManager.GetUser();
                    }

                    // not the file owner!
                    if (user == null || user.UserID != uploadedFile.UserId)
                    {
                        context.Response.Clear();
                        context.Response.Write("You do not have access to download this file!");
                        context.Response.StatusCode = (int)HttpStatusCode.Forbidden;
                        context.Response.Flush();
                        context.Response.End();
                        return;
                    }
                }

                // file path
                var fileName = UploadedFileManager.MapToPhysicalPath(uploadedFile);

                // reading file info
                var fileInfo   = new FileInfo(fileName);
                var fileLength = fileInfo.Length;

                // Download information class
                using (var downloadInfo = new DownloadDataInfo(fileName))
                {
                    downloadInfo.DisplayFileName = UploadedFileManager.GetUrlFileName(uploadedFile);

                    // Reading request download range
                    var requestedRanges = HeadersParser.ParseHttpRequestHeaderMultipleRange(context.Request, fileLength);

                    // apply the ranges to the download info
                    downloadInfo.InitializeRanges(requestedRanges);

                    string etagMatched;
                    int    outcomeStausCode = 200;

                    // validating the ranges specified
                    if (!HeadersParser.ValidatePartialRequest(context.Request, downloadInfo, out etagMatched, ref outcomeStausCode))
                    {
                        // the request is invalid, this is the invalid code
                        context.Response.StatusCode = outcomeStausCode;

                        // show to the client what is the real ETag
                        if (!string.IsNullOrEmpty(etagMatched))
                        {
                            context.Response.AppendHeader("ETag", etagMatched);
                        }

                        // stop the preoccess
                        // but don't hassle with error messages
                        return;
                    }

                    // user ID, or IP or anything you use to identify the user
                    //var userIP = context.Request.UserHostAddress;

                    // Option 1: limiting the download speed for this file for this user!
                    //UserSpeedLimitManager.StartNewDownload(downloadInfo, userIP, DownloadLimit);

                    // Option 2: Limiting only this connection
                    downloadInfo.LimitTransferSpeed(DownloadLimit);

                    // It is very important to destory the DownloadProcess object
                    // Here the using block does it for us.
                    using (var process = new DownloadProcess(downloadInfo))
                    {
                        var state = DownloadProcess.DownloadProcessState.None;
                        try
                        {
                            // start the download
                            state = process.ProcessDownload(context.Response);
                        }
                        catch (HttpException)
                        {
                            // preventing:
                            // System.Web.HttpException (0x800703E3): The remote host closed the connection. The error code is 0x800703E3.
                        }

                        // checking the state of the download
                        if (state == DownloadProcess.DownloadProcessState.LastPartfinished)
                        {
                            // all parts of download are finish, do something here!
                            using (var db = new UploadDb())
                            {
                                var dbFile = db.Files.FirstOrDefault(a => a.UploadedFileID == uploadedFile.UploadedFileID);
                                if (dbFile != null)
                                {
                                    dbFile.Downloaded++;
                                    dbFile.LastDownload = DateTime.Now.ToUniversalTime();
                                    db.SaveChanges();
                                }
                            }
                        }
                    }
                }
            }
            catch (Exception ex)
            {
                SiteException.LogException(ex, "ID: " + idStr);
                throw;
            }
        }