I am Migrating one of projects to .NET CORE MVC ,
Previous code had API to Upload document, re-written same
Rewritten Above Code to below code , used "using
Microsoft.AspNetCore.Mvc.WebApiCompatShim" to get HttpRequestMessage
[Older Code: Working Fine in .NET FRAMEWORK]
public HttpResponseMessage UploadFile(string filetype)//old code
{
Stream file = Request.Content.ReadAsStreamAsync().Result;
string id;
id = DocumentHelper.SaveDocument(filetype, file);
return Request.CreateResponse<string>(HttpStatusCode.OK, id);
}
public HttpResponseMessage UploadFile(string filetype)//Re-Written Code
{
HttpRequestMessageFeature requestMessage = new HttpRequestMessageFeature(Request.HttpContext);
HttpRequestMessage httpRequestMessage = requestMessage.HttpRequestMessage;
Stream file = httpRequestMessage.Content.ReadAsStreamAsync().Result;
string id;
id = DocumentHelper.SaveDocument(filetype, file);
return httpRequestMessage.CreateResponse<string>(HttpStatusCode.OK, id);
}
Quickwatch for ReWritten Code when trying to read content
[1]: https://i.stack.imgur.com/cc4AF.png
Tried using Request.Body with stream reader, and enabled buffering.
Any Pointers How to read the stream from Microsoft.AspNetCore.HTTP.HttpRequest,I AM TRYING TO AVOID async function that would force me to change return type
Related
I'm creating a .NET Core 3.1 web api method to download a pdf for a given filename. This method is shared across teams where their client code is generated using NSwag.
I recently changed produces attribute to Produces("Application/pdf") from json, this change is required so other teams can generate valid client code. However since this change, I haven't been able to download any files from this method. Requests to download documents return with a 406 error (in Postman) and the following error is logged to the server event viewer.
No output formatter was found for content types 'application/pdf, application/pdf' to write the response.
Reverting the produced content-type to 'application/json' does allow documents to be downloaded, but as mentioned, this value is required to be pdf.
Any suggestions would be greatly appreciated.
Method:
[HttpGet("{*filePath}")]
[ProducesResponseType(typeof(FileStreamResult), StatusCodes.Status200OK)]
[ProducesResponseType(StatusCodes.Status404NotFound)]
[ProducesResponseType(StatusCodes.Status400BadRequest)]
[ProducesResponseType(StatusCodes.Status401Unauthorized)]
[Produces("Application/pdf")]
public async Task<ActionResult> GetDocument(string fileName) {
RolesRequiredHttpContextExtensions.ValidateAppRole(HttpContext, _RequiredScopes);
var memoryStream = new MemoryStream();
var memoryStream = new MemoryStream();
using (var stream = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.Read, bufferSize: 4096, useAsync: true)) {
stream.CopyTo(memoryStream);
}
memoryStream.Seek(offset: 0, SeekOrigin.Begin);
return new FileStreamResult(memoryStream, "Application/pdf");
}
I just came across the same error and after some investigation I found out that the cause of the exception was indeed in the model binding error. You already wrote about it in your answer, but on closer inspection it became obvious that the reason was not related to binding itself, rather to the response body.
Since you specified [Produces("application/pdf")] the framework assumes this content type is the only possible for this action, but when an exception is thrown, you get application/json containing error description instead.
So to make this work for both "happy path" and exceptions, you could specify multiple response types:
[Produces("application/pdf", "application/json")]
public async Task<ActionResult> GetDocument(string fileName)
{
...
}
I'am using
public asnyc Task<IActionResult> BuildPDF()
{
Stream pdfStream = _pdfService.GetData();
byte[] memoryContent = pdfStream.ToArray();
return File(memoryContent, "application/pdf");
}
and it works. Could you please try?
The issue was caused by renaming the method parameter and not updating [HttpGet("{*filePath}")] to [HttpGet("{*fileName}")]
I had the same error, it is very confusing in some cases.
I got this error after adding new parameter of type int[] to my method forgetting [FromQuery] attribute for it.
After adding [FromQuery] attribute error gone.
I have searched high and low for this one and can't seem to find a way of accessing the Request.Content in an MVC web api. I basically am trying to create a File Service to and from Azure Blob and Table storage (table for storing metadata about the file, blob for the actual file)....
I was converting the steps in the following link, but this is where I have come unstuck
the back end I have working but can't find a way of the new unified controller passing a fileobject from json post through to the service! Any ideas would be greatly appreciated as always... or am I just going about this the wrong way?
Article here....
UPDATE: so to clarify, what I am trying to do in the new MVC 6 (where you no longer have an apicontroller to inherit from) is to access a file that has been uploaded to the api from a JSON post. That is the long and short of what I am trying to achieve.
I am trying to use the article based on the old Web API which uses the Request.Content to access it, however even if I use the WebAPIShim which they provide I still come unstuck with other objects or properties that are no longer available so I'm wondering if I need to approach it a different way, but either way, all I am trying to do is to get a file from a JSON post to a MVC 6 Web api and pass that file to my back end service....
ANY IDEAS?
Here is an example without relying on model binding.
You can always find the request data in Request.Body, or use Request.Form to get the request body as a form.
[HttpPost]
public async Task<IActionResult> UploadFile()
{
if (Request.Form.Files != null && Request.Form.Files.Count > 0)
{
var file = Request.Form.Files[0];
var contentType = file.ContentType;
using (var fileStream = file.OpenReadStream())
{
using (var memoryStream = new MemoryStream())
{
await fileStream.CopyToAsync(memoryStream);
// do what you want with memoryStream.ToArray()
}
}
}
return new JsonResult(new { });
}
If the only thing in your request is a File you can use the IFormFile class in your action:
public FileDetails UploadSingle(IFormFile file)
{
FileDetails fileDetails;
using (var reader = new StreamReader(file.OpenReadStream()))
{
var fileContent = reader.ReadToEnd();
var parsedContentDisposition = ContentDispositionHeaderValue.Parse(file.ContentDisposition);
fileDetails = new FileDetails
{
Filename = parsedContentDisposition.FileName,
Content = fileContent
};
}
return fileDetails;
}
I am working on pdf generation, it is successfully implemented using itextsharp.dll. It’s working fine on local environment after publish also. We have our own server at other site
But same code doesn't work on the server,pdf is not generated instead it gives an error: 'The document has no pages.'
Initially I thought it is due to no data in document but it works locally with or without data in the document.
I had code implemented as follows to make a web request Is any problem in that ??
try
{
var myHttpWebRequest = (HttpWebRequest)WebRequest.Create(strPdfData + "?objpatId=" + patID);
var response = myHttpWebRequest.GetResponse();
myHttpWebRequest.Timeout = 900000;
var stream = response.GetResponseStream();
StreamReader sr = new StreamReader(stream);
content = sr.ReadToEnd();
}
create a method in the controller:
[HttpGet]
public JsonResult GetFile()
{
var json = new WebClient().DownloadFile(string address, string fileName);
//This code is just to convert the file to json you can keep it in file format and send to the view
dynamic result = Newtonsoft.Json.JsonConvert.DeserializeObject(json);
var oc = Newtonsoft.Json.JsonConvert.DeserializeObject<countdata[]>(Convert.ToString(result.countdata));
return Json(oc, JsonRequestBehavior.AllowGet);
}
In the view just call this function:
#Url.Action('genPDF','GetFile');
I have a simple WCF service that exposes a REST endpoint, and fetches files from a BLOB container. The service returns the file as a stream. i stumbled this post about closing the stream after the response has been made :
http://devdump.wordpress.com/2008/12/07/disposing-return-values/
This is my code:
public class FileService
{
[OperationContract]
[WebGet(UriTemplate = "{*url}")]
public Stream ServeHttpRequest(string url)
{
var fileDir = Path.GetDirectoryName(url);
var fileName = Path.GetFileName(url);
var blobName = Path.Combine(fileDir, fileName);
return getBlob(blobName);
}
private Stream getBlob(string blobName)
{
var account = CloudStorageAccount.FromConfigurationSetting("ConnectingString");
var client = account.CreateCloudBlobClient();
var container = client.GetContainerReference("data");
var blob = container.GetBlobReference(blobName);
MemoryStream ms = new MemoryStream();
blob.DownloadToStream(ms);
ms.Seek(0, SeekOrigin.Begin);
return ms;
}
}
So I have two question :
Should I follow the pattern mentioned in the post ?
If I change my return type to Byte[], what are Cons/Pros ?
( My client is Silverlight 4.0, just in case it has any effect )
I'd consider changing your return type to byte[]. It's tidier.
Stream implements IDisposable, so in theory the consumer of your method will need to call your code in a using block:
using (var receivedStream = new FileService().ServeHttpRequest(someUrl))
{
// do something with the stream
}
If your client definitely needs access to something that Stream provides, then by all means go ahead and return that, but by returning a byte[] you keep control of any unmanaged resources that are hidden under the covers.
OperationBehaviorAttribute.AutoDisposeParameters is set to TRUE by default which calls dispose on all the inputs/outputs that are disposable. So everything just works.
This link :
http://devdump.wordpress.com/2008/12/07/disposing-return-values/
explains how to manually control the process.
I am trying to upload MS-Excel file through WCF-REST Service.
I used the solution given in below post:-
RESTful WCF service image upload problem
My POST Method is declared as:
[OperationContract]
[WebInvoke(Method = "POST", UriTemplate = "/RFQ")]
[WebContentType("application/octet-stream")]
void UploadRFQDoc(Stream fileContents);
When I debug, stream content is fine till the call goes, and when I attach service to debug, Stream fileContents parameter becomes null , and service returns with [Bad Request]. I am not sending large file (it is just 50 KB). I am using HttpClient to call the Post.
Here are the client code(RestClient is HttpClient).
protected void Post(string uri, Stream stream, int length)
{
var content = HttpContent.Create(output => CopyToStream(stream, output, length), "application/octet-stream", length);
Uri relativeUri = new Uri(uri, UriKind.Relative);
var resp = RestClient.Post(relativeUri, content);
ProcessResponse(resp);
}
void CopyToStream(Stream input, Stream output, int length)
{
var buffer = new byte[length];
var read = input.Read(buffer, 0, Convert.ToInt32 (length));
output.Write(buffer, 0, read);
}
Any clue what else can go wrong.
Many Thanks.
[WebContentType("application/octet-stream")] attribute was unnecessary here. I commented it out, and all worked fine :).