public IActionResult Download([FromRoute] string id)
{
// Below is a naive implementation which does not fully make use of streaming, resulting
// in OutOfMemoryExceptions when retrieving larger payloads.
////var filePath = Path.Combine(_persistenceLocation, $"{id}");
////var metaFilePath = Path.Combine(_persistenceLocation, $"{id}.meta");
////if (System.IO.File.Exists(filePath) == false)
////{
//// return NotFound();
////}
////var result = new FileStreamResult(System.IO.File.OpenRead(filePath), "application/octet-stream");
////if (System.IO.File.Exists(metaFilePath))
////{
//// var meta = MetaFileParser.Parse(metaFilePath);
//// if (meta != null && !String.IsNullOrWhiteSpace(meta.OriginalFileName))
//// {
//// result.FileDownloadName = meta.OriginalFileName;
//// }
////}
////return result;
// The solution below uses a custom made FileResult implementation which does not buffer the contents
// in memory, allowing larger payloads to be transmitted via streaming.
// The implementation of the StreamedFileResult class is almost identical to the FileStreamResult class,
// except that the StreamedFileResult flushes each time bytes are written to the target-stream.
var filePath = Path.Combine(_persistenceLocation, $"{id}");
var metaFilePath = Path.Combine(_persistenceLocation, $"{id}.meta");
if (System.IO.File.Exists(filePath) == false)
{
return(NotFound());
}
string filedownloadName = $"{id}.download";
if (System.IO.File.Exists(metaFilePath))
{
var meta = MetaFileParser.Parse(metaFilePath);
if (!String.IsNullOrWhiteSpace(meta?.OriginalFileName))
{
filedownloadName = meta.OriginalFileName;
}
}
var result = new StreamedFileResult(System.IO.File.OpenRead(filePath), filedownloadName, "application/octet-stream");
return(result);
}
public void ReturnsExpectedResult()
{
const string expectedContent = "message data!";
using (var contentStream = new MemoryStream(Encoding.UTF8.GetBytes(expectedContent)))
{
var streamedFileResult = new StreamedFileResult(contentStream, "download-filename", "content-type");
StreamedFileResultAssert.OnContent(
streamedFileResult: streamedFileResult,
assertion: actualContent => Assert.Equal(expectedContent, actualContent));
}
}
public async Task DownloadsTheUploadedFileFromController()
{
// Arrange
using (var contentStream = new MemoryStream())
{
PayloadController controller = AnonymousPayloadController;
await SerializeExpectedContentStream(contentStream, controller);
AssignRequestUri(controller.ControllerContext.HttpContext.Request);
// Act
var actualResult = await controller.Upload() as ObjectResult;
// Assert
var actualUploadResult = actualResult?.Value as UploadResult;
Assert.True(IsDownloadUrlAMatch(actualUploadResult), $"Actual Request Uri doesn't match the expected Uri '{ExpectedRequestUri}'");
StreamedFileResult downloadResult = await DownloadPayload(controller, actualUploadResult);
StreamedFileResultAssert.OnContent(
downloadResult, actualContent => Assert.Equal(ExpectedContent, actualContent));
}
}
