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Passing potential huge files in chunks to Web API

I have to pass potential huge files from an ASP.NET Core middle Server to an ASP.NET backend.
I can’t use the ASP.NET backend web API directly, I have to go over a MVC Controller.
Currently my middle Server gets the file in Chunks (and does some verification), saves it to disk and after it completes it rereads it in chunks to pass it forward.
Is there an easy way to pass the chunks without buffering the file?
I currently got this:
MVC Controler:
[HttpPost]
public ActionResult UploadChunk(IFormFile fileChunk, string chunkMetadata)
{
if (!string.IsNullOrEmpty(chunkMetadata))
{
var metaDataObject = JsonConvert.DeserializeObject<ChunkMetadata>(chunkMetadata);
...
AppendContentToFile(tempFilePath, fileChunk); //writes file with FileMode.Append,
}
}
my upload to back end [Edit]:
public IHttpActionResult FileUpload(string fileUri)
{
try
{
if (Request.Content.IsMimeMultipartContent())
{
var configProvider = Resolve<IApplicationConfigurationProvider>();
var uploadRootDir = configProvider.TemporaryFileUploadPath;
var streamProvider = new MultipartStreamProvider(uploadRootDir);
// If the file is huge and is not split into chunks, the 'ReadAsMultipartAsync' call
// takes as long as full file has been copied
var readResult = Request.Content.ReadAsMultipartAsync(streamProvider).Result;
var fileSvc = Resolve<IFileService>();
string targetFilePath = string.Empty;
foreach (MultipartFileData fileData in streamProvider.FileData)
{
ContentDispositionHeaderValue contentDisposition = fileData.Headers.ContentDisposition;
string fileName = contentDisposition.FileName;
if (!GetFileName(fileName, out var targetFileName))
{
return BadRequest($"ContentDisposition.FileName must match 'file' of URI-query! Actual: {targetFileName}");
}
var rawSourceFileInfo = new FileInfo(targetFileName);
if (contentDisposition.Size.HasValue && contentDisposition.Size.Value > 0)
{
if (!fileSvc.CreateNewFilePath(fileUri, new PathOptions(true), out var validFileFullPath))
{
return BadRequest($"Unable to create physical-path from fileId='{fileUri}'");
}
targetFilePath = validFileFullPath.FullName;
fileSvc.AddChunk(validFileFullPath.FullName, contentDisposition.Size.Value, fileData.LocalFileName);
}
else
{
return BadRequest("File upload must set a valid file-length in ContentDisposition");
}
}
return Ok(targetFilePath);
}
else
{
return BadRequest("File upload must be a 'IsMimeMultipartContent'");
}
}
catch (Exception error)
{
LogError(error, "FileUpload");
return InternalServerError(error);
}
}
Thanks in advance for any help!
[Edit]
my not working call from client to back end:
<script>
$(document).ready(function (e) {
$("#uploadImage").on('change', (function (e) {
// append file input to form data
var fileInput = document.getElementById('uploadImage');
var file = fileInput.files[0];
var formData = new FormData();
formData.append('uploadImage', file);
$.ajax({
url: "http://localhost/service/filestore/v1/upload?fileUri=someText",
type: "POST",
data: formData,
contentType: false,
cache: false,
processData: false,
success: function (data) {
if (data == 'invalid') {
// invalid file format.
$("#err").html("Invalid File !").fadeIn();
}
else {
// view uploaded file.
$("#preview").html(data).fadeIn();
$("#form")[0].reset();
}
},
error: function (e) {
$("#err").html(e).fadeIn();
}
});
}));
});
</script>

Error "Requested JSON parse failed" in downloading excel file

I have an action method which returns an excel file in return. I am calling that action method using ajax. I am getting Requested JSON parse failed.
$.ajax({
url: importUrl,
data: {
X: "12",
Y: "12",
Z: "12"
},
success: function (data) {
alert("S: "+data);
},
error: function (jqXHR, exception) {
var msg = '';
if (jqXHR.status === 0) {
msg = 'Not connect.\n Verify Network.';
} else if (jqXHR.status == 404) {
msg = 'Requested page not found. [404]';
} else if (jqXHR.status == 500) {
msg = 'Internal Server Error [500].';
} else if (exception === 'parsererror') {
msg = 'Requested JSON parse failed.';
} else if (exception === 'timeout') {
msg = 'Time out error.';
} else if (exception === 'abort') {
msg = 'Ajax request aborted.';
} else {
msg = 'Uncaught Error.\n' + jqXHR.responseText;
}
console.log(msg);
}
});
public ActionResult ExportReportToExcel(string X, string Y, string Z)
{
if (HttpContext.Request.UrlReferrer == null)
TempData["PDFPrevUrl"] = Url.RouteUrl("PageNotFound");
else if (TempData["PDFPrevUrl"] == null)
TempData["PDFPrevUrl"] = HttpContext.Request.UrlReferrer.PathAndQuery;
var customer = _authenticationService.CurrentCustomer;
if (customer == null)
return new LmsHttpUnauthorizedResult();
string filename = "Report";
try
{
XLWorkbook wb = new XLWorkbook(Server.MapPath(#"~/Content/CumulativePerformanceReportTemplate.xlsx"));
XElement userprogress = XElement.Load(Server.MapPath(#"~/Content/Export.xml")).Element("cumulativeperformancereport");
int datarow = int.Parse(userprogress.Element("T").Attribute("row").Value.Trim());
int datacol = int.Parse(userprogress.Element("T").Attribute("col").Value.Trim());
IXLWorksheet WS = wb.Worksheet(1);
WS.Cell(datarow, datacol).Value = customer.Name;
datarow = int.Parse(userprogress.Element("X").Attribute("row").Value.Trim());
datacol = int.Parse(userprogress.Element("X").Attribute("col").Value.Trim());
WS.Cell(datarow, datacol).Value = X;
datarow = int.Parse(userprogress.Element("Y").Attribute("row").Value.Trim());
datacol = int.Parse(userprogress.Element("Y").Attribute("col").Value.Trim());
WS.Cell(datarow, datacol).Value = Y;
datarow = int.Parse(userprogress.Element("Z").Attribute("row").Value.Trim());
datacol = int.Parse(userprogress.Element("Z").Attribute("col").Value.Trim());
WS.Cell(datarow, datacol).Value = Z;
Response.Clear();
Response.Buffer = true;
Response.Charset = "";
Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
Response.AddHeader("content-disposition", "attachment;filename=" + filename + "_Summary.xlsx");
using (MemoryStream MyMemoryStream = new MemoryStream())
{
wb.SaveAs(MyMemoryStream);
MyMemoryStream.WriteTo(Response.OutputStream);
Response.Flush();
Response.End();
}
return null;
}
catch (Exception ex)
{
return Redirect(TempData["PDFPrevUrl"].ToString());
}
}
Why am I getting this error?

"Requested JSON parse failed" indicating that AJAX call expects to get JSON data as returned value, but the controller action method returns other data type than JSON object.
By reviewing controller flow and omitting some non-relevant code, you will get this:
public ActionResult ExportReportToExcel(string X, string Y, string Z)
{
// other stuff
var customer = _authenticationService.CurrentCustomer;
if (customer == null)
return new LmsHttpUnauthorizedResult();
try
{
// other stuff
return null; // this returns null value instead of expected JSON
}
catch (Exception ex)
{
return Redirect(TempData["PDFPrevUrl"].ToString());
}
}
By default jQuery tries to infer dataType argument based on the MIME type of the response (xml, json, script or html, most recent default is JSON). Hence, you need to return a JSON object through these methods below:
// ContentResult
return Content("message_text", "application/json");
// JsonResult
return Json("message_text", JsonRequestBehavior.AllowGet);
If you want returning file by AJAX to download, you can use window.location or window.location.href to redirect:
$.ajax({
url: importUrl, // this should be refer to JsonResult action
data: {
X: "12",
Y: "12",
Z: "12"
},
success: function (data) {
// deal with data response here
window.location = downloadUrl; // redirect to FileResult action
},
error: function (jqXHR, exception) {
// other stuff
}
}
// example controller to return Excel binary file
public FileResult DownloadFile(string fileName)
{
// other stuff
byte[] content = TempData["something"] as byte[];
return File(content, "application/vnd.ms-excel", fileName);
}
NB: The explanations above are mostly trivial, your current implementation may differ from given examples.
Similar issues:
Download Excel file via AJAX MVC
jQuery returning "parsererror" for ajax request

Why use Backend for something like creating an excel file & then downloading it.... its overkill & downloading part is difficut
use something light weight like Javascript on the client side... it will create excel from XML & will download it using the download
property...
var data_type = 'data:application/vnd.ms-excel';
var table_div = document.getElementById('table_wrapper');
var table_html = table_div.outerHTML.replace(/ /g, '%20');
Here is Solution

It could be a server side error in sending the file.
Have you tried changing the response Content Type to application/vnd.ms-excel ?
I show you a minimal working example
// Server side
public ActionResult GimmeFile()
{
var bytes = System.IO.File.ReadAllBytes(#"path_to_your_file.xlsx");
return File(bytes, "application/vnd.ms-excel", "Myfile.xls");
}
Client side with your Ajax call
$.ajax({
method: 'POST',
url: '/Home/GimmeFile',
success: function (data) {
alert("S: " + data)
},
error: function (jqXHR, ex) {
console.log(ex)
}
})
Anyway, I don't know what you need to do with the excel file after ajax call,
but if your need is to save it to local then you should use the HTML5 < a download> instead

Why am I getting a 500 Internal Error, no caught exceptions?

Controller:
[HttpPost]
public ActionResult HtmlToPdf ( String html )
{
try
{
var filename = DateTime.Now.Ticks.ToString() + ".pdf";
using (MemoryStream ms = new MemoryStream())
{
var pdf = TheArtOfDev.HtmlRenderer.PdfSharp.PdfGenerator.GeneratePdf(html, PdfSharp.PageSize.A4);
pdf.Save(Server.MapPath("~/Dumps/") + filename);
}
return Json(new { filename = filename });
}
catch ( Exception e )
{
return Json(new { msg = e.Message });
}
}
AJAX:
$('#download-as-pdf').click(function () {
//var resultsHtml = $(this).closest('html').html();
var resultsHtml = "<html><head></head><body><p>Hey there</p></body></html>";
$.ajax({
url: '/Answers/HtmlToPdf',
method: 'POST',
data: { html: resultsHtml },
success: function (retobj) {
console.log(retobj);
},
error: function (retobj) {
console.log("The error callback was called");//TEST
}
});
})
I know the controller is getting called because if I set resultsHtml = undefined then I get back an error from the controller
{msg: "Cannot save a PDF document with no pages."}
So what is going on here? Any ideas?

Have you checked if the folder you specified has R/W permissions for IUSR/IIS?
I would put a breakpoint and debug precisely this line:
pdf.Save(Server.MapPath("~/Dumps/") + filename);

It seems you are saving a empty pdf and i thinks it is your problem, your html parameter must has some content to generate pdf in below code:

IE11 saves file from Web API without extension

I have Angular SPA which downloads a file from ASP.NET Web API 2 using the following approach:
Angular Code
$scope.downloadFile = function(httpPath) {
// Use an arraybuffer
$http.get(httpPath, { responseType: 'arraybuffer' })
.success( function(data, status, headers) {
var octetStreamMime = 'application/octet-stream';
var success = false;
// Get the headers
headers = headers();
// Get the filename from the x-filename header or default to "download.bin"
var filename = headers['x-filename'] || 'download.bin';
// Determine the content type from the header or default to "application/octet-stream"
var contentType = headers['content-type'] || octetStreamMime;
try
{
// Try using msSaveBlob if supported
console.log("Trying saveBlob method ...");
var blob = new Blob([data], { type: contentType });
if(navigator.msSaveBlob)
navigator.msSaveBlob(blob, filename);
else {
// Try using other saveBlob implementations, if available
var saveBlob = navigator.webkitSaveBlob || navigator.mozSaveBlob || navigator.saveBlob;
if(saveBlob === undefined) throw "Not supported";
saveBlob(blob, filename);
}
console.log("saveBlob succeeded");
success = true;
}
catch(ex)
{
console.log("saveBlob method failed with the following exception:");
console.log(ex);
}
if(!success)
{
// Get the blob url creator
var urlCreator = window.URL || window.webkitURL || window.mozURL || window.msURL;
if(urlCreator)
{
// Try to use a download link
var link = document.createElement('a');
if('download' in link)
{
// Try to simulate a click
try
{
// Prepare a blob URL
console.log("Trying download link method with simulated click ...");
var blob = new Blob([data], { type: contentType });
var url = urlCreator.createObjectURL(blob);
link.setAttribute('href', url);
// Set the download attribute (Supported in Chrome 14+ / Firefox 20+)
link.setAttribute("download", filename);
// Simulate clicking the download link
var event = document.createEvent('MouseEvents');
event.initMouseEvent('click', true, true, window, 1, 0, 0, 0, 0, false, false, false, false, 0, null);
link.dispatchEvent(event);
console.log("Download link method with simulated click succeeded");
success = true;
}
catch(ex) {
console.log("Download link method with simulated click failed with the following exception:");
console.log(ex);
}
}
if(!success)
{
// Fallback to window.location method
try
{
// Prepare a blob URL
// Use application/octet-stream when using window.location to force download
console.log("Trying download link method with window.location ...");
var blob = new Blob([data], { type: octetStreamMime });
var url = urlCreator.createObjectURL(blob);
window.location = url;
console.log("Download link method with window.location succeeded");
success = true;
} catch(ex) {
console.log("Download link method with window.location failed with the following exception:");
console.log(ex);
}
}
}
}
if(!success)
{
//Fallback to window.open method
console.log("No methods worked for saving the arraybuffer, using last resort window.open");
window.open(httpPath, '_blank', '');
}
})
.error(function(data, status) {
console.log("Request failed with status: " + status);
// Optionally write the error out to scope
$scope.errorDetails = "Request failed with status: " + status;
});
};
httpPath is a url of my Web API Controller. The controller has the following code:
Web API Code
[HttpGet]
[Authorize]
public async Task<HttpResponseMessage> DownloadItems(string path)
{
try
{
Stream stream = await documentsRepo.getStream(path);
HttpResponseMessage result = Request.CreateResponse(HttpStatusCode.OK);
result.Content = new StreamContent(stream);
result.Content.Headers.ContentDisposition =
new System.Net.Http.Headers.ContentDispositionHeaderValue("attachment")
{
FileName = "document.zip",
};
result.Content.Headers.ContentType = new System.Net.Http.Headers.MediaTypeHeaderValue("application/octet-stream");
result.Content.Headers.ContentLength = stream.Length;
return result;
}
catch (Exception e)
{
return Request.CreateResponse(HttpStatusCode.InternalServerError, e);
}
}
The above setup works perfectly well in all browsers (a .zip file is downloaded), except IE11.
For unknown reason, IE11 downloads the file without .zip extension
Any idea what could be wrong with my API Controller?

Stop Execution of HTTPPOST ActionMethod in MVC

I have webApplication in MVC Framework..
i have situation where i have to provide user to export some data to csv file
for that i have written following code ..
[HttpPost]
public ActionResult ExportReportToFile(ReportCriteriaViewModels posdata, string name)
{
string strQuery = GetReportQuery(posdata, name);
IEnumerable<REP_MM_DEMOGRAPHIC_CC> lstDemographics = ReportDataAccess.GetReportData<REP_MM_DEMOGRAPHIC_CC>(strQuery);
if (lstDemographics.Count() > 0)
return new CsvActionResult<REP_MM_DEMOGRAPHIC_CC>(lstDemographics.ToList(), "LISDataExport.csv");
else
return view(posdata);
}
Above code works fine... if in listResult Count is Greater than zero then i returns File to download.. but if i dont get any records in lstDemographics then i returns view..
My problem is when i dont get any result in lstDemographics, i dont want to return view coz it refreshes whole view.. so is there any way where we can stop execution of Action Method and browser doesn't refresh the view and stay as it is..
Thanks..

You will have to make an AJAX call to stop page refresh.
To achieve file export, we actually broke the process in two AJAX calls. First call sends a request to server, server prepare a file and store it in temp table. Server return the file name to AJAX call if there is data. If no data or error, it return a JSON result to indicate a failure.
On success, view make another AJAX request to download the file passing file name.
Something like this:
[Audit(ActionName = "ExportDriverFile")]
public ActionResult ExportDriverFile(int searchId, string exportType, string exportFormat)
{
var user = GetUser();
var driverSearchCriteria = driverSearchCriteriaService.GetDriverSearchCriteria(searchId);
var fileName = exportType + "_" + driverSearchCriteria.SearchType + "_" + User.Identity.Name.Split('#')[0] + "." + exportFormat;
//TempData["ExportBytes_" + fileName] = null;
_searchService.DeleteTempStore(searchId);
var exportBytes = exportService.ExportDriverFileStream(driverSearchCriteria, searchId, exportType, exportFormat, user.DownloadCode, user.OrganizationId);
if (exportBytes != null)
{
var tempStore = new TempStore
{
SearchId = searchId,
FileName = fileName,
ExportFormat = exportFormat,
ExportType = exportType,
DataAsBlob = exportBytes
};
var obj = _searchService.AddTempStore(tempStore);
return Json(fileName);
}
else
{
return Json("failed");
}
}
[HttpGet]
public ActionResult DownloadStream(string fileName, int searchId)
{
var tempStore = _searchService.GetTempStore(searchId);
var bytes = tempStore.DataAsBlob;
if (bytes != null)
{
var stream = new MemoryStream(bytes);
// TempData["ExportBytes_" + fileName] = null;
_searchService.DeleteTempStore(searchId);
return File(stream, "application/vnd.ms-excel", fileName);
}
_logger.Log("Export/DownloadStream request failed", LogCategory.Error);
return Json("Failed");
}
At client side, we do something like:
function ExportData(exportType, exportFormat) {
var searchId = document.getElementById('hfSelectedDriverId').value;
var model = { searchId: searchId, exportType: exportType, exportFormat: exportFormat };
//$('div[class=ajax_overlay]').remove();
//alert("The file will be downloaded in few minutes..");
$.ajax({
url: '#Url.Action("ExportDriverFile", "Export")',
contentType: 'application/json; charset=utf-8',
type: 'POST',
dataType: 'html',
data: JSON.stringify(model)
})
.success(function (result) {
result = result.toString().replace(/"/gi, "");
if (result == "" || result == "failed")
{
alert("File download failed. Please try again!");
}
else
{
window.location = '/Export/DownloadStream?fileName=' + result+"&searchId="+searchId;
}
})
.error(function (xhr, status) {
//
//alert(status);
});
//$('div[class=ajax_overlay]').remove();
}

You should create javascript function with $.getJSON method.
On controller side you just have to check, if you get data from database then return file path else return message.
Your JS code should be something like this:
$.getJSON(url)
.done(function (data) {
if (data.filePath) // If get data, fill filePath
window.location = data.filePath;
else
alert(data.msg);
});
And from controller you can create a HTTPGET Action method that return JSON data like:
return Json(new { msg = "No data found" }, JsonRequestBehavior.AllowGet);
Based on condition you can simple change msg with filePath.