如何通过Web API中的post请求接收流和对象？

Question

I'm currently developing a REST web service using Web API.

Now I am trying to receive stream file and object through the post.

When I sent it without the JobPosition object I received the file correctly, also when I sent the JobPosition without the file I received the JobPosition correctly.

But when I sent the stream file and the object through the postman I receive the error.

I would appreciate your help to understand if this is possible, and if so, the direction that will help me.

public class JobPosition
{
    public int Id { set; get; }
    public string Title { set; get; }
}

[HttpPost]
[Route("Job")]
public async Task<bool> Post(JobPosition job)
{
    var multipartMemoryStreamProvider = new MultipartMemoryStreamProvider();
    await Request.Content.ReadAsMultipartAsync(multipartMemoryStreamProvider, new CancellationToken());
    var stream = await multipartMemoryStreamProvider.Contents[0].ReadAsStreamAsync();
    // implementaion
    return true;
}

Postman request:

I tried all the possible combinations with the Content-Type with no success.

Answer 1

Remove the (JobPosition job) action function parameter, and instead read that with your own code via the multipartMemoryStreamProvider object.

await multipartMemoryStreamProvider.Contents[0].ReadAsStreamAsync(); //Stream
await multipartMemoryStreamProvider.Contents[1].ReadAsStreamAsync(); //JSON

Something like that. The order will be important. It's best if you instead assume it could come in any order, loop over the Contents collection, and handle according to the name of the variable.

Answer 2

If you are using .NET core, can you try this?

public class JobPosition
{
    public int Id { set; get; }
    public string Title { set; get; }
    public IFormFile jobFile {set; get; }
}

[HttpPost]
[Route("Job")]
public async Task<bool> Post(JobPosition job)
{
    if (!Request.ContentType.Contains("multipart/form-data"))
    {
        return BadRequest();
    }

    // your implementation
    // you can access the file by job.jobFile
    // you can read the contents of the file by opening a read stream from the file object and read it to a byte[]
    return true;
}

More on IFormFile here.

Answer 3

Maybe you can use the FormData provided by the MultipartFormDataStreamProvider to extract the JobPosition.

    public async Task<IHttpActionResult> PostUploadFile()
    {
        // Check if the request contains multipart/form-data.
        if (!Request.Content.IsMimeMultipartContent())
        {
            throw new HttpResponseException(HttpStatusCode.UnsupportedMediaType);
        }

        string root = HttpContext.Current.Server.MapPath("~/App_Data");
        var provider = new MultipartFormDataStreamProvider(root);

        try
        {
            // Read the form data.
            await Request.Content.ReadAsMultipartAsync(provider);

            NameValueCollection formdata = provider.FormData;

            JobPosition jobPosition = new JobPosition()
            {
                Id = formdata["Id"],
                Title = bool.Parse(formdata["Title"])
            };

            foreach (MultipartFileData file in provider.FileData)
            {
                var fileName = file.Headers.ContentDisposition.FileName.Replace("\"", string.Empty);
                byte[] documentData = File.ReadAllBytes(file.LocalFileName);


                /// Save document documentData to DB or where ever
                /// --- TODO
            }
            return Ok(jobPosition);
        }
        catch (System.Exception e)
        {
            return BadRequest(e.Message);
        }
    }