I am currently uploading a file via the kendo fileuploader to an api controller using ASP.NET core RC-1. I am receiving a periodic error of "object reference not set to instance of object" when attempting to read the stream following opening the stream with IFormFile.OpenReadStream().
My controller is:
[HttpPost]
[Route("api/{domain}/[controller]")]
public async Task<IActionResult> Post([FromRoute]string domain, [FromForm]IFormFile file, [FromForm]WebDocument document)
{
if (ModelState.IsValid)
{
if (file.Length > 0)
{
var userName =
Request.HttpContext.User.Claims
.FirstOrDefault(c => c.Type == ClaimTypesEx.FullName)?
.Value;
var uploadedFileName =
ContentDispositionHeaderValue.Parse(file.ContentDisposition).FileName.Trim('"');
document.Domain = domain;
document.MimeType = file.ContentType;
document.SizeInBytes = file.Length;
document.ChangedBy = userName;
document.FileName = (string.IsNullOrEmpty(document.FileName)) ? uploadedFileName : document.FileName;
try
{
document = await CommandStack.For<WebDocument>()
.AddOrUpdateAsync(document, file.OpenReadStream()).ConfigureAwait(false);
}
catch (Exception e)
{
return new HttpStatusCodeResult(500);
}
return Ok(document);
}
}
return new BadRequestResult();
}
And the error is being thrown when I actually try to read the stream when it is going into blob storage:
public async Task<Uri> CreateOrUpdateBlobAsync(string containerName, string fileName, string mimeType,
Stream fileStream)
{
var container = Client.GetContainerReference(containerName);
var blob = container.GetBlockBlobReference(fileName);
//Error HERE
await blob.UploadFromStreamAsync(fileStream);
blob.Properties.ContentType = mimeType;
await blob.SetPropertiesAsync();
return blob.Uri;
}
What I am having trouble with is this is sporadic and there seems to be no defined pattern of which files are accepted and which ones generate the error. At first I thought it might be a size issue but that is not the case as I have several larger files uploaded successfully and then one small file will throw the error. Images seem to work fine and it is hit or miss on other file types with no rhyme or reason that I can figure out.
Related
I have my web api that uploads and reads an excel file from the client app and then afterwards saves the data into the database, the application works perfect on locally server but the problem comes when the application is deployed to azure server it returns error 500 internal server error therefore i don't understand why this happens and and don't know how i can track to understand what might be the cause below are my code blocks.
My Interface Class
public interface UploadExcelInterface
{
Task UploadMultipleClients(Client obj);
}
My Service Implementation
public class UploadExcelService : UploadExcelInterface
{
private readonly DbContext _connect;
private readonly IHttpContextAccessor httpContextAccessor;
public UploadExcelService(DbContext _connect, IHttpContextAccessor httpContextAccessor)
{
this._connect = _connect;
this.httpContextAccessor = httpContextAccessor;
}
public async Task UploadMultipleClients(Client obj)
{
var file = httpContextAccessor.HttpContext.Request.Form.Files[0];
if (file != null && file.Length > 0)
{
var folderName = Path.Combine("Datas", "ClientUPloads");
var pathToSave = Path.Combine(Directory.GetCurrentDirectory(), folderName);
var fileName = Guid.NewGuid() + ContentDispositionHeaderValue.Parse(file.ContentDisposition).FileName.Trim('"');
var fullPath = Path.Combine(pathToSave, fileName);
var clientsList = new List<Client>();
using (var fileStream = new FileStream(fullPath, FileMode.Create))
{
await file.CopyToAsync(fileStream);
FileInfo excelFile = new FileInfo(Path.Combine(pathToSave, fileName));
ExcelPackage.LicenseContext = LicenseContext.NonCommercial;
using (ExcelPackage package = new ExcelPackage(excelFile))
{
ExcelWorksheet worksheet = package.Workbook.Worksheets[0];
var rowcount = worksheet.Dimension.Rows;
for (int row = 2; row <= rowcount; row++)
{
var Names = (worksheet.Cells[row,2].Value ?? string.Empty).ToString().Trim();
var Address = (worksheet.Cells[row,3].Value ?? string.Empty).ToString().Trim();
var Title = (worksheet.Cells[row,4].Value ?? string.Empty).ToString().Trim();
var Product = (worksheet.Cells[row,5].Value ?? string.Empty).ToString().Trim();
var Order = (worksheet.Cells[row,6].Value ?? string.Empty).ToString().Trim();
var Email = (worksheet.Cells[row,7].Value ?? string.Empty).ToString().Trim();
var Price = (worksheet.Cells[row,8].Value ?? string.Empty).ToString().Trim();
clientsList.Add(new Client
{
Names = Names,
Address = Address,
Title = Title,
Product = Product,
Order = Order,
Email = Email,
Price = Price,
}
}
//adding clients into the database
foreach (Client client in clientsList)
{
var exist = _connect.client.Any(x => x.Email == client.Email);
if (!exist)
{
await _connect.client.AddAsync(client);
}
}
await _connect.SaveChangesAsync();
}
}
}
My Controller Class
[HttpPost]
public async Task UploadMultipleClients([FromForm] Client obj)
{
await uploadExcelInterface.UploadMultipleClients(obj);
}
}
Please any help regarding this error that am getting from the server, and addition on that is it possible to get the data from the excel file without uploading it to server if yes how? because i tried adding the file to memory stream an reading it from memory but it appers not work, any suggestions thanks.
My answer may not help you solve the problem directly, but it can locate the error step by step. After we fix the error, we should be able to solve the problem in this thread.
Suggestions
Please make sure you have inclue EPPlus library in your deploy content.
Enabling ASP.NET Core stdout log (Windows Server)
Azure App Service - Configure Detailed Error Logging
Why
After tested, I am sure azure webapp can support EPPlus. For 500 error, as we don't have a more specific error message to refer to, we can't quickly locate the problem. Following the suggested method, you will surely see some useful information.
E.g:
The class library of EPPlus was not found.
Folders such as Datas are not created.
The database connection string, the test environment and the production environment may be different.
...
We are exploring using Aspose.Words for some conversions in an on premise API.
This works perfectly for Excel sheets using Aspose.Cells.
[HttpPost]
[Route("convert/excel")]
public async Task<IActionResult> ConvertExcel(IFormFile fileToConvert)
{
var fileStream = new MemoryStream();
fileToConvert.CopyTo(fileStream);
var convertedFile = await pdfConverter.ConvertExcelAsync(fileStream);
return File(convertedFile, "application/octet-stream");
}
However when using exactly the same method for Aspose.Words it does nothing, literally nothing just continues for a few minutes and then times out. This is not a timeout issue with the conversion as the file is 200KB.
[HttpPost]
[Route("convert/word")]
public async Task<IActionResult> ConvertWord(IFormFile fileToConvert)
{
var fileStream = new MemoryStream();
fileToConvert.CopyTo(fileStream);
var convertedFile = await pdfConverter.ConvertWordAsync(fileStream);
return File(convertedFile, "application/octet-stream");
}
I have tried various forms of returning a file but no luck.
return new FileStreamResult(convertedFile, "application/pdf");
The actual conversion methods look like this.
public Task<Stream> ConvertWordAsync(Stream fileStream)
{
return Task.Factory.StartNew(() => ConvertWord(fileStream));
}
private Stream ConvertWord(Stream inputFile)
{
var doc = new Document(inputFile);
var outputFile = new MemoryStream();
doc.Save(outputFile, Aspose.Words.SaveFormat.Pdf);
//doc.Save(#"C:\ProgramData\foo.pdf", Aspose.Words.SaveFormat.Pdf); //THIS WORKS BUT NOT APPOPRIATE
return outputFile;
}
I have also updated it to support HttpGet and hard-coded a path to a file and in browser just get a Download failed - network error.
Is is possible that the Save method returns the memory stream at the end of the stream.
You should try the following immediately after the call to doc.Save
outputFile.Seek(0, SeekOrigin.Begin);
I am trying to upload a file from my angular code to an ASP.net backend.
My Angular code sends the object using FormData:
public uploadFiles(files) {
console.log(files);
if(files.length < 1) return;
const formData = new FormData();
files.forEach(file => {
console.log(file);
formData.append(file.name, file);
})
this._http.postFile('/order-processing/import-orders','application/x-www-form-urlencoded' ,formData).pipe(finalize(() => {
console.log("Finalized");
})).subscribe((val: any) => {
console.log('ORDER SUBMITTED', val);
}, error => {
console.log(error);
});
}
With the post file method looking like:
public postFile(path: string, contentType:string, body: FormData) : Observable<any> {
let headers = {
'Content-Type': contentType,
'Authorization': this.authToken
}
return this._http.post(environment.API_URL + path, body, {
headers
});
}
My ASP.net endpoint looks like:
[HttpPost, Route("hospitality/order-processing/import-orders")]
[RequestSizeLimit(2147483648)]
[DisableRequestSizeLimit]
public IActionResult UploadFile()
{
try
{
//var req = Request.Form.Files;
var file = Request.Form.Files;
string folderName = "Uploads";
string webRootPath = _hostingEnvironment.WebRootPath;
string newPath = Path.Combine(webRootPath, folderName);
if (!Directory.Exists(newPath))
{
Directory.CreateDirectory(newPath);
}
return Json("Upload Successful.");
}
catch (Exception e)
{
return Json("Failed:" + e);
}
}
If I check the network tab on my browser when I send the file, it says that my object is in the call, great, but for some reason it doesn't get picked up on the backend and when I step through the code it is not there.
I get different errors when I modify this code slightly. The error for the code in the state it is in now is "Form key or value length limit 2048 exceeded", however sometimes I get array out of bounds errors, or content boundary limit exceeded errors, it's enough to make you want to slam you face into your keyboard continually.
The whole point of this is to be able to upload an excel file to ASP.net code running in an AWS lambda, which then inserts rows in a RDS database. Am I going about this the right way? Is there a better way to achieve what I am trying to do? If not then what is wrong with my code that doesn't allow me to upload a file to a Web API?!
Thanks
It seems that you're trying to set the limit of the request but the message states that the problem is with form key or value length.
Try setting the RequestFormLimits and check if that helps.
[HttpPost, Route("hospitality/order-processing/import-orders")]
[RequestFormLimits(KeyLengthLimit = 8192, ValueLengthLimit = 8192)]
public IActionResult UploadFile()
I have a file being uploaded using http post request using multipart/form-data to my class that is extending from ApiController.
In a dummy project, I am able to use:
HttpPostedFileBase hpf = Request.Files[file] as HttpPostedFileBase
to get the file inside my controller method where my Request is of type System.Web.HttpRequestWrapper.
But inside another production app where I have constraints of not adding any libraries/dlls, I don't see anything inside System.Web.HttpRequestWrapper.
My simple requirement is to get the posted file and convert it to a byte array to be able to store that into a database.
Any thoughts?
This code sample is from a ASP.NET Web API project I did sometime ago. It allowed uploading of an image file. I removed parts that were not relevant to your question.
public async Task<HttpResponseMessage> Post()
{
if (!Request.Content.IsMimeMultipartContent())
throw new HttpResponseException(HttpStatusCode.UnsupportedMediaType);
try
{
var provider = await Request.Content.ReadAsMultipartAsync(new MultipartMemoryStreamProvider());
var firstImage = provider.Contents.FirstOrDefault();
if (firstImage == null || firstImage.Headers.ContentDisposition.FileName == null)
return Request.CreateResponse(HttpStatusCode.BadRequest);
using (var ms = new MemoryStream())
{
await firstImage.CopyToAsync(ms);
var byteArray = ms.ToArray();
}
return Request.CreateResponse(HttpStatusCode.Created);
}
catch (Exception ex)
{
return Request.CreateErrorResponse(HttpStatusCode.InternalServerError, ex);
}
}
I have an asp.net MVC website which is consuming a rest api to receive it's data. I'm using asynchronous tasks to perform the requests as there can be many on each page. After a while of uptime the website has been throwing the following error when trying to receive data.
The underlying connection was closed: An unexpected error occurred on a send.
I read that this could be due to the maxconnection settings on the web.config but increasing this doesn't seem to make much difference.
I'm also using caching to reduce the load on the api. The task is cached so the result can be used later.
The only way I've found to fix this is by recycling the application pool. Any help would be appreciated.
/* Code from page_load */
var currenciesTask = ApiClient.GetAsync<CurrencyListWrapper>("currencies");
var blogArticleTask = ApiClient.GetAsync<BlogArticleListWrapper>("blog/articles", "limit=10");
var seoPageTask = ApiClient.GetAsync<SEOPageListWrapper>("seopages");
await Task.WhenAll(currenciesTask, blogArticleTask, seoPageTask);
/* Code from data access later */
public class ApiClient : HttpClient
{
public static Task<T> GetAsync<T>(string operation, string query = null, bool cache = true)
{
// Check if task is in cache
string cacheName = null;
if (cache)
{
cacheName = String.Format("{0}_{1}_{2}", operation, query ?? String.Empty, App.GetLanguage());
var cachedTask = HttpRuntime.Cache[cacheName];
if (cachedTask != null)
{
return (Task<T>)cachedTask;
}
}
// Get data task
var task = GetAsyncData<T>(operation, query);
// Add to cache if required
if (task != null && cache)
{
App.AddToCache(cacheName, task);
}
return task;
}
public static async Task<T> GetAsyncData<T>(string operation, string query = null)
{
using (ApiClient client = new ApiClient())
{
string url;
if (query != null)
{
url = String.Format("{0}?{1}", operation, query);
}
else
{
url = String.Format("{0}", operation);
}
var response = await client.GetAsync(url);
return (await response.Content.ReadAsAsync<T>());
}
}
}
This is wrong,
The task is cached so the result can be used later.
You are supposed to cache result, not the task. At end of first execution, your HttpClient is closed and when you try to retrieve cached task, it will not work.
public class ApiClient : HttpClient
{
public static async Task<T> GetAsync<T>(string operation, string query = null, bool cache = true)
{
// Check if task is in cache
string cacheName = null;
if (cache)
{
cacheName = String.Format("{0}_{1}_{2}", operation, query ?? String.Empty, App.GetLanguage());
T cachedResult = (T)HttpRuntime.Cache[cacheName];
if (cachedResult!= null)
{
return Task.FromResult(cachedResult);
}
}
// Get data task
var result = await GetAsyncData<T>(operation, query);
// Add to cache if required
if (result != null && cache)
{
App.AddToCache(cacheName, result);
}
return result;
}
public static async Task<T> GetAsyncData<T>(string operation, string query = null)
{
using (ApiClient client = new ApiClient())
{
string url;
if (query != null)
{
url = String.Format("{0}?{1}", operation, query);
}
else
{
url = String.Format("{0}", operation);
}
var response = await client.GetAsync(url);
return (await response.Content.ReadAsAsync<T>());
}
}
}
Akash could be right.
But it seems more or less connection issue with application pool. Set the connection limit 0 to make it unlimited at application pool.
Have a finally block in you code, and
gc.collect();
garbage collection method to be called to remove unused connections to make space for other connection.