public static async Task <HugeMemoryStream> ProcessStreamedFile(
MultipartSection section, ContentDispositionHeaderValue contentDisposition,
ModelStateDictionary modelState, string[] permittedExtensions, long sizeLimit)
{
try
{
var memoryStream = new HugeMemoryStream();
await section.Body.CopyToAsync(memoryStream);
// Check if the file is empty or exceeds the size limit.
if (memoryStream.Length == 0)
{
modelState.AddModelError("Error", "The file is empty.");
}
else if (memoryStream.Length > sizeLimit)
{
var megabyteSizeLimit = sizeLimit / 1048576;
modelState.AddModelError("Error", $"The file exceeds {megabyteSizeLimit:N1} MB.");
}
else if (!IsValidFileExtensionAndSignature(contentDisposition.FileName.Value, memoryStream, permittedExtensions))
{
modelState.AddModelError("Error", $"The file type isn't permitted or the file's signature doesn't match the file's extension. {Path.GetExtension(contentDisposition.FileName.Value).ToLowerInvariant()}");
}
else
{
if (!IsValidFileExtensionAndSignature(memoryStream, permittedExtensions))
{
modelState.AddModelError("Error", $"The file type isn't permitted or the file's signature doesn't match the file's extension. {FindMimeHelpers.GetMimeFromStream(memoryStream)} - {FindMimeHelpers.GetExtensionsFromStream(memoryStream)[0]}");
}
return(memoryStream);
}
}
catch (Exception ex)
{
modelState.AddModelError("Error", $"The upload failed. Please contact the Help Desk for support. Error: {ex.Message}");
modelState.AddModelError("Exception", ex.Message);
modelState.AddModelError("StackTrace", ex.StackTrace);
}
return(new HugeMemoryStream());
}
public async Task <IActionResult> UploadFileStream()
{
string fileNameFinaliy = "";
try
{
if (!MultipartRequestHelper.IsMultipartContentType(Request.ContentType))
{
ModelState.AddModelError("Error", $"The request couldn't be processed (Error -1).");
return(BadRequest(ModelState));
}
if (!MultipartRequestHelper.ValidateAntiforgeryToken(Request.Headers))
{
ModelState.AddModelError("Error", $"The request couldn't be processed (Error 0).");
return(BadRequest(ModelState));
}
var formAccumulator = new KeyValueAccumulator();
var trustedFileNameForDisplay = string.Empty;
var streamedFileContent = new HugeMemoryStream();
var boundary = MultipartRequestHelper.GetBoundary(MediaTypeHeaderValue.Parse(Request.ContentType), _defaultFormOptions.MultipartBoundaryLengthLimit);
var reader = new MultipartReader(boundary, HttpContext.Request.Body);
var section = await reader.ReadNextSectionAsync();
if (section == null)
{
ModelState.AddModelError("Error", $"The request couldn't be processed (Error 1).");
return(BadRequest(ModelState));
}
while (section != null)
{
var hasContentDispositionHeader = ContentDispositionHeaderValue.TryParse(section.ContentDisposition, out var contentDisposition);
if (hasContentDispositionHeader)
{
if (MultipartRequestHelper.HasFileContentDisposition(contentDisposition))
{
trustedFileNameForDisplay = WebUtility.HtmlEncode(contentDisposition.FileName.Value);
streamedFileContent = await FileHelpers.ProcessStreamedFile(section, contentDisposition, ModelState, _permittedExtensions, _fileSizeLimit);
if (!ModelState.IsValid)
{
return(BadRequest(ModelState));
}
}
else if (MultipartRequestHelper.HasFormDataContentDisposition(contentDisposition))
{
var key = HeaderUtilities.RemoveQuotes(contentDisposition.Name).Value;
var encoding = GetEncoding(section);
if (encoding == null)
{
ModelState.AddModelError("Error", $"The request couldn't be processed (Error 2).");
return(BadRequest(ModelState));
}
using (var streamReader = new StreamReader(
section.Body,
encoding,
detectEncodingFromByteOrderMarks: true,
bufferSize: 1024,
leaveOpen: true))
{
var value = await streamReader.ReadToEndAsync();
if (string.Equals(value, "undefined", StringComparison.OrdinalIgnoreCase))
{
value = string.Empty;
}
formAccumulator.Append(key, value);
if (formAccumulator.ValueCount > _defaultFormOptions.ValueCountLimit)
{
ModelState.AddModelError("Error", $"The request couldn't be processed (Error 3).");
return(BadRequest(ModelState));
}
}
}
}
if (!ModelState.IsValid)
{
return(BadRequest(ModelState));
}
section = await reader.ReadNextSectionAsync();
}
// Bind form data to the model
var formData = new FormData();
var formValueProvider = new FormValueProvider(BindingSource.Form, new FormCollection(formAccumulator.GetResults()), CultureInfo.CurrentCulture);
var bindingSuccessful = await TryUpdateModelAsync(formData, prefix : "", valueProvider : formValueProvider);
if (!bindingSuccessful)
{
ModelState.AddModelError("Error", "The request couldn't be processed (Error 5).");
return(BadRequest(ModelState));
}
if (string.IsNullOrEmpty(trustedFileNameForDisplay) || streamedFileContent.Length <= 0)
{
ModelState.AddModelError("Error", "The request couldn't be processed (Error 6).");
return(BadRequest(ModelState));
}
if (!ModelState.IsValid)
{
return(BadRequest(ModelState));
}
string trustedFileNameForFileStorage = Path.GetRandomFileName();
fileNameFinaliy = Path.Combine(_targetFilePath, trustedFileNameForFileStorage);
string mimeType = FindMimeHelpers.GetMimeFromStream(streamedFileContent);
using (var targetStream = System.IO.File.Create(fileNameFinaliy))
{
streamedFileContent.CopyTo(targetStream);
_logger.LogInformation($"Uploaded file '{trustedFileNameForDisplay}' saved to '{_targetFilePath}' as {trustedFileNameForFileStorage}");
}
var model = await SaveInDb(HttpContext.Request.HttpContext.Connection.RemoteIpAddress.ToString(), fileNameFinaliy, trustedFileNameForDisplay, trustedFileNameForFileStorage, streamedFileContent.Length, mimeType);
return(new OkObjectResult(model.Hash.Trim().ToLower()));
}
catch (Exception ex)
{
if (!string.IsNullOrEmpty(fileNameFinaliy) && System.IO.File.Exists(fileNameFinaliy))
{
System.IO.File.Delete(fileNameFinaliy);
}
ModelState.AddModelError("Error", ex.Message);
if (ex.InnerException != null)
{
ModelState.AddModelError("InnerException", ex.InnerException.Message);
}
return(BadRequest(ModelState));
}
}