/// <summary>
/// Get the response header made by the current http request.
/// download request can be resumed, so correct header must be set
/// </summary>
/// <param name="httpRequest"></param>
/// <param name="fileInfo"></param>
/// <returns></returns>
private HttpResponseHeader GetResponseHeader(gFileItem file)
{
if (_httpContext.Request == null || file == null)
{
return(null);
}
long startPosition = 0;
string contentRange = "";
string fileName = file.Name;
long fileLength = file.Size;
string lastUpdateTimeStr = file.LastModified.ToString();
string eTag = HttpUtility.UrlEncode(fileName, Encoding.UTF8) + " " + lastUpdateTimeStr;
string contentDisposition = "attachment;filename=" + HttpUtility.UrlEncode(fileName, Encoding.UTF8).Replace("+", "%20");
if (_httpContext.Request.Headers["Range"] != StringValues.Empty)
{
string[] range = _httpContext.Request.Headers["Range"].ToString().Split(new char[] { '=', '-' });
startPosition = Convert.ToInt64(range[1]);
if (startPosition < 0 || startPosition >= fileLength)
{
return(null);
}
}
if (_httpContext.Request.Headers["If-Range"].ToString() != null)
{
if (_httpContext.Request.Headers["If-Range"].ToString().Replace("\"", "") != eTag)
{
startPosition = 0;
}
}
string contentLength = (fileLength - startPosition).ToString();
if (startPosition > 0)
{
contentRange = string.Format(" bytes {0}-{1}/{2}", startPosition, fileLength - 1, fileLength);
}
HttpResponseHeader responseHeader = new HttpResponseHeader
{
AcceptRanges = "bytes",
Connection = "Keep-Alive",
ContentDisposition = contentDisposition,
ContentEncoding = Encoding.UTF8,
ContentLength = contentLength,
ContentRange = contentRange,
ContentType = "application/octet-stream",
Etag = eTag,
LastModified = lastUpdateTimeStr
};
return(responseHeader);
}
/// <summary>
/// Send the download file to the client.
/// </summary>
private async Task SendDownloadFile(HttpResponseHeader responseHeader, Stream fileStream, double speed)
{
if (_httpContext.Response == null || responseHeader == null)
{
return;
}
if (!string.IsNullOrEmpty(responseHeader.ContentRange))
{
_httpContext.Response.StatusCode = 206;
// Set the start position of the reading files.
string[] range = responseHeader.ContentRange.Split(new char[] { ' ', '=', '-' });
fileStream.Position = Convert.ToInt64(range[2]);
}
_httpContext.Response.Clear();
_httpContext.Features.Get <IHttpResponseBodyFeature>().DisableBuffering();
_httpContext.Response.Headers.Add("Accept-Ranges", responseHeader.AcceptRanges);
_httpContext.Response.Headers.Add("Connection", responseHeader.Connection);
_httpContext.Response.Headers.Add("Content-Disposition", responseHeader.ContentDisposition);
// httpContext.Response.ContentEncoding = responseHeader.ContentEncoding;
_httpContext.Response.Headers.Add("Content-Length", responseHeader.ContentLength);
if (!string.IsNullOrEmpty(responseHeader.ContentRange))
{
_httpContext.Response.Headers.Add("Content-Range", responseHeader.ContentRange);
}
_httpContext.Response.ContentType = responseHeader.ContentType;
_httpContext.Response.Headers.Add("Etag", "\"" + responseHeader.Etag + "\"");
_httpContext.Response.Headers.Add("Last-Modified", responseHeader.LastModified);
byte[] buffer = new byte[10240];
long fileLength = Convert.ToInt64(responseHeader.ContentLength);
// Send file to client.
while (fileLength > 0)
{
if (!_httpContext.RequestAborted.IsCancellationRequested)
{
int length = fileStream.Read(buffer, 0, 10240);
await _httpContext.Response.Body.WriteAsync(buffer, 0, length);
await _httpContext.Response.Body.FlushAsync();
fileLength -= length;
// Throttle write speed
var sleep = Math.Ceiling((buffer.Length / (1000.0 * speed)) * 1000.0);
Thread.Sleep(int.Parse(sleep.ToString()));
}
else
{
fileLength = -1;
}
}
}
private async Task StartDownload(HttpResponseHeader responseHeader, string filePath, double speed)
{
FileStream fileStream = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
try
{
await SendDownloadFile(responseHeader, fileStream, speed);
}
catch (Exception ex)
{
_httpContext.Response.StatusCode = 500;
#region Trace
_logger.LogError(ex.Message);
#endregion
}
finally
{
fileStream.Close();
fileStream?.Dispose();
}
}
private async Task <DownloadStatus> StartDownload(HttpResponseHeader responseHeader, string filePath, double speed)
{
DownloadStatus status = DownloadStatus.UNKNOWN;
FileStream fileStream = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
try
{
_logger.LogInformation($"Start sending file: {filePath} to client.");
status = await SendDownloadFile(responseHeader, fileStream, speed);
}
catch (Exception ex)
{
_httpContext.Response.StatusCode = 500;
#region Trace
_logger.LogError(ex.Message);
#endregion
}
finally
{
fileStream.Close();
fileStream?.Dispose();
}
return(status);
}
public async Task <StartDownloadResult> Handle(StartDownloadCommand request, CancellationToken cancellationToken)
{
StartDownloadResult Result = new StartDownloadResult();
gDownloadFileRequest downloadRequest = new gDownloadFileRequest()
{
DownloadId = request.DownloadId,
RequesterAddress = _httpContext.Request.Host.Value
};
// query the api
gDownloadFileResponse dResponse = await _fileMngClient.GetDownloadFileAsync(downloadRequest);
if (dResponse == null)
{
Result.ErrorContent = new ErrorContent("No response has been received from the server.", ErrorOrigin.Server);
return(Result);
}
if (dResponse.Status.Status != Protos.RequestStatus.Success)
{
Result.ErrorContent = new ErrorContent(dResponse.Status.Message, ErrorOrigin.None);
return(Result);
}
string filePath = Path.Combine(_uploadOpt.UploadPath, dResponse.FileItem.UserId, dResponse.FileItem.Id, dResponse.FileItem.Id);
// Check file exist on disk
if (!File.Exists(filePath))
{
_httpContext.Response.StatusCode = 404;
Result.ErrorContent = new ErrorContent("File not found, it may have been moved or deleted!", ErrorOrigin.Server);
return(Result);
}
// Check file is not too large
if (dResponse.FileItem.Size > uint.MaxValue) // ~4Gb
{
_httpContext.Response.StatusCode = 413;
Result.ErrorContent = new ErrorContent("File is too large!", ErrorOrigin.Server);
return(Result);
}
// Get the response header information made by the current http request.
HttpResponseHeader responseHeader = GetResponseHeader(dResponse.FileItem);
if (responseHeader == null)
{
Result.ErrorContent = new ErrorContent("Invalid response header!", ErrorOrigin.Server);
return(Result);
}
// All good, start download
var dStatus = await StartDownload(responseHeader, filePath, dResponse.DownloadSpeed);
// Once download is completed we send request to increment download count
if (dStatus == DownloadStatus.COMPLETED)
{
await _fileMngClient.FileDownloadCompletedAsync(new gDownloadCompletedRequest()
{
FileId = dResponse.FileItem.Id,
RequesterIp = _httpContext.Request.Host.Value
});
}
else
{
_logger.LogInformation("Download request status: " + dStatus);
}
return(null);
}
