How to receive a byte array and header content in a ASP.NET Core Web API Controller

Question

I need to receive a content together with a byte array in a c# ASP.NET Core Web API application.

**--HttpClient (console Application)**  

                Dictionary<int, byte[]> fileparts = new Dictionary<int, byte[]>();
                int bufferSize = 1000 * 1024;

                byte[] buffer;
                string filePath = @"D:\Extra\Songs\test.mp3";
                using (FileStream fileData = File.OpenRead(filePath))
                {
                    int index = 0;
                    int i = 1;
                    while (fileData.Position < fileData.Length)
                    {

                        if (index + bufferSize > fileData.Length)
                        {
                            buffer = new byte[(int)fileData.Length - index];
                            fileData.Read(buffer, 0, ((int)fileData.Length - index));
                        }
                        else
                        {
                            buffer = new byte[bufferSize];
                            fileData.Read(buffer, 0, bufferSize);
                        }

                        fileparts.Add(i, buffer);
                        index = (int)fileData.Position;
                        i++;
                    }
                }
                
 while (fileparts.Count() != 0)
 {               
      var data = fileparts.First();          
  var fileContent = new ByteArrayContent(data);//byte content
    fileContent.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment") { FileName = "test" };
                        fileContent.Headers.Add("id", id);
                        fileContent.Headers.Add("name", name);
                        fileContent.Headers.Add("length", length);
                        if (fileparts.Count() == 1)
                          fileContent.Headers.Add("IsCompleted", "true");
                        else
                          fileContent.Headers.Add("IsCompleted", "false");
                          
                    using (var content = new MultipartFormDataContent())
                    {
                       content.Add(fileContent);
                       // Make a call to Web API 
                        var result = client.PostAsync("/api/file", fileContent).Result;
                        if (result.StatusCode == System.Net.HttpStatusCode.OK)
                            fileparts.Remove(data.Key);
                    }

**--WebApi Core ApiController**

    public class FileController : Controller
    {
        [HttpPost]
        public async Task<IActionResult> Post()
        {
    /*i need to get the content here , for some reason existing .NET libraries does not work here
    like 
        MultipartMemoryStreamProvider provider = new MultipartMemoryStreamProvider();
        FilePart part = null;
       
        await Request.Content.ReadAsMultipartAsync(provider); -- request.content not available 
        using (Stream fileStream = await provider.Contents[0].ReadAsStreamAsync())
                {
                    part = provider.Contents[0].Headers.GetData(); //public static FilePart GetData name,length,id 
                    part.Data = fileStream.ReadFully();
    */    
    }

the back end I have working but can't find a way of the new asp.net core controller parsing fileobject and data from client post through to the service! Any ideas would be greatly appreciated as always...

you are passing the ByteArrayContent to the controller but not the MultipartFormDataContent are you sure about this? — Niladri
– Niladri, Commented Sep 27, 2017 at 16:20
in this line var result = client.PostAsync("/api/file", fileContent).Result; — Niladri
– Niladri, Commented Sep 27, 2017 at 16:20
Hi @Niladri yes It's a mistake, it should be var result = client.PostAsync("/api/file", content).Result; not fileContent — Lakmal
– Lakmal, Commented Sep 27, 2017 at 17:06

Niladri · Accepted Answer · 2017-09-27 17:34:36Z

3

You can modify your controller action method like below to accept ByteArrayContent OR MultipartFormDataContent as required. I have used [FromBody] attribute for the model binding in POST.

Here is more info on [FromBody]

https://learn.microsoft.com/en-us/aspnet/core/mvc/models/model-binding

public class FileController : Controller
    {
        [HttpPost]
        public async Task<IActionResult> Post([FromBody] MultipartFormDataContent content)
        {
         MultipartMemoryStreamProvider provider = new MultipartMemoryStreamProvider();
        FilePart part = null;
         // access the content here 
         await content.ReadAsMultipartAsync(provider);
        // rest of the code
       }
   }

as discussed before you should be using content to post to this API like below

var result = client.PostAsync("/api/file", content).Result;

edited Sep 27, 2017 at 17:34

answered Sep 27, 2017 at 16:27

Niladri

5,9922 gold badges27 silver badges45 bronze badges

Sign up to request clarification or add additional context in comments.

9 Comments

Lakmal Over a year ago

With [FromBody] attribute client exit with 'UnsupportedMediaType', it seems not reach the server side POST.

Niladri Over a year ago

@Lakmal which version of web api are you using ?

Niladri Over a year ago

@Lakmal have you changed it to var result = client.PostAsync("/api/file", content).Result;

Lakmal Over a year ago

you mean "Microsoft.AspNet.WebApi.Client": "5.2.3", "Microsoft.AspNetCore.Mvc": "1.0.1" ?

Lakmal Over a year ago

Yes, var result = client.PostAsync("/api/file", content).Result;

|

alec · Accepted Answer · 2017-09-27 17:22:42Z

2

I've used this sucessfully in the past:

[HttpPost]
public async Task<IActionResult> Post(IFormFile formFile)
{
    using (Stream stream = formFile.OpenReadStream())
    {
         //Perform necessary actions with file stream
    }
}

I believe you'll also need to change your client code to match the parameter name:

fileContent.Headers.Add("name", "formFile");

answered Sep 27, 2017 at 17:22

alec

3961 silver badge6 bronze badges

Collectives™ on Stack Overflow

How to receive a byte array and header content in a ASP.NET Core Web API Controller

2 Answers 2

9 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

9 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related