EonaCat.Logger/Testers/EonaCat.Logger.Test.Web/Logger.cs

using EonaCat.Logger.Managers;
using Microsoft.AspNetCore.Http.Features;
using Microsoft.AspNetCore.Mvc;
using System.Net;

namespace EonaCat.Logger.Test.Web
{
    public static class Logger
    {
        private static readonly LogManager LogManager = new LogManager(new LoggerSettings
        {
            Id = "EonaCatDnsLogger",
            MaxLogType = ELogType.TRACE,
            FileLoggerOptions =
            {
                LogDirectory = "Logs",
                FileSizeLimit = 20_000_000, // 20 MB
            }
        });

        public static string LogFolder => "Logs";
        public static string CurrentLogFile => LogManager.CurrentLogFile;
        public static bool IsDisabled { get; set; }

        public static void DeleteCurrentLogFile()
        {
            if (IsDisabled)
                return;

            LogManager.DeleteCurrentLogFile();
        }

        internal static IActionResult DownloadLogAsync(HttpResponse response, string logFile)
        {
            if (IsDisabled)
            {
                response.StatusCode = (int)HttpStatusCode.BadRequest;
                return null;
            }

            // Check if the file exists
            if (!File.Exists(logFile))
            {
                response.StatusCode = (int)HttpStatusCode.BadRequest;
                return null;
            }

            // Create a cancellation token source to handle cancellation
            var cancellationTokenSource = new CancellationTokenSource();

            // Start streaming the file content to the response
            Task.Run(() => StreamFileContentAsync(response, logFile, response.Body, cancellationTokenSource.Token), cancellationTokenSource.Token);

            // Return an empty result to indicate that streaming has started
            return new EmptyResult();
        }

        private static void DisableResponseBuffering(HttpResponse response)
        {
            var httpContext = response.HttpContext;
            var responseBodyFeature = httpContext.Features.Get<IHttpResponseBodyFeature>();
            if (responseBodyFeature != null)
            {
                responseBodyFeature.DisableBuffering();
            }
        }

        private static async Task StreamFileContentAsync(HttpResponse response, string filePath, Stream outputStream, CancellationToken cancellationToken)
        {
            using (var fileStream = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite, 4096, FileOptions.Asynchronous | FileOptions.SequentialScan))
            {
                try
                {
                    // Clear the response first
                    response.Clear();

                    // Disable response buffering
                    DisableResponseBuffering(response);

                    // Set the response headers
                    response.Headers.Add("Content-Disposition", $"attachment; filename={Path.GetFileName(filePath)}");
                    response.Headers.Add("Content-Type", "application/octet-stream");

                    byte[] buffer = new byte[4096];
                    int bytesRead;
                    while ((bytesRead = await fileStream.ReadAsync(buffer, 0, buffer.Length, cancellationToken).ConfigureAwait(false)) > 0)
                    {
                        if (cancellationToken.IsCancellationRequested)
                        {
                            break;
                        }

                        // Check if the response is completed
                        if (response.HasStarted)
                        {
                            // The response is already completed, so we can't write further
                            break;
                        }

                        try
                        {
                            await outputStream.WriteAsync(buffer, 0, bytesRead, cancellationToken).ConfigureAwait(false);
                        }
                        catch (Exception)
                        {
                            // Do nothing, handle any specific error if needed
                        }

                        // Check if the file has been modified
                        if (File.GetLastWriteTimeUtc(filePath) > File.GetLastWriteTimeUtc(fileStream.Name))
                        {
                            // Close the existing stream and reopen the file with updated contents
                            fileStream.Close();
                            await StreamFileContentAsync(response, filePath, outputStream, cancellationToken).ConfigureAwait(false);
                            return;
                        }
                    }
                }
                catch (OperationCanceledException)
                {
                    // The operation was canceled, clean up if necessary
                    fileStream.Close();
                }
                finally
                {

                    try
                    {
                        // Flush and close the output stream
                        await outputStream.FlushAsync(cancellationToken).ConfigureAwait(false);
                    }
                    catch (ObjectDisposedException e)
                    {
                        Log(e, "StreamFileContentAsync");
                    }
                    finally
                    {
                        outputStream?.Close();
                    }
                }
            }
        }




        public static void Log(string message, ELogType logType = ELogType.INFO, bool writeToConsole = true)
        {
            if (IsDisabled)
                return;

            LogManager.Write(message, logType, writeToConsole);
        }

        public static void Log(Exception exception, string message = "", bool writeToConsole = true)
        {
            if (IsDisabled)
                return;

            LogManager.Write(exception, module: message, writeToConsole: writeToConsole);
        }
    }
}