Hello together,

I am trying to implement the uploading of large files for the frontend user in my Umbraco 11 site. Unfortunately, this ends in an exception: System.IO.IOException: Unexpected end of Stream, the content may have already been read by another component.

In a simple MVC .net core application my code works, but with Umbraco 11 I can't get it to work. What am I missing here so that the stream is not preloaded?

[DisableFormValueModelBinding] doesn't seem to work, but the code there is executed.

Here is my code (I left out everything irrelevant, like error handling etc.)

The form element used to upload the file(s)

<form id="uploadForm"
  action="/fileupload/UploadToFilesystem"
  method="POST"
  enctype="multipart/form-data"
  >
<dl>
    <dt>
        <label for="file">Files to upload</label>
    </dt>
    <dd>
        <input data-id="file" type="file" name="file" />
    </dd>
</dl>

<input class="btn" type="submit" value="upload" />

<div>
    <output form="uploadForm" name="result"></output>
</div></form>

My controller:

public class FileUploadController : ControllerBase // Controller  - have tried both
{
    [HttpPost]
    [MultipartFormData]
    [DisableFormValueModelBinding]
    public async Task<IActionResult> UploadToFilesystem()
    {
        string strTargetFilePath = Path.Combine(objFiles.dgGetRootPath(), dgFilesConfig.cstrDataFilesTmp);
        // is something like D:\...\umbracosite\data\tmp at the moment

    boundary = HeaderUtilities.RemoveQuotes(Request.ContentType).Value;

    var reader = new MultipartReader(boundary, HttpContext.Request.Body);
    var section = await reader.ReadNextSectionAsync();
    // this is the point where the server error 500 occurs
    // System.IO.IOException: Unexpected end of Stream, the content may have already been read by another component.

    // the rest of the code comes here, but it doesn't matter for now.

Herewith I try to prevent model binding (checked during debugging, the code is executed):

[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method)]
public class DisableFormValueModelBindingAttribute : Attribute, IResourceFilter
{
    public void OnResourceExecuting(ResourceExecutingContext context)
    {
        var factories = context.ValueProviderFactories;

        var formValueProviderFactory = context.ValueProviderFactories.OfType<FormValueProviderFactory>().FirstOrDefault();
        if (formValueProviderFactory != null)
        {
            factories.RemoveType<FormValueProviderFactory>();
            //checked during debugging, the code is executed
        }

        var formFileValueProviderFactory = context.ValueProviderFactories.OfType<FormFileValueProviderFactory>().FirstOrDefault();
        if (formFileValueProviderFactory != null)
        {
            factories.RemoveType<FormFileValueProviderFactory>();
            //checked during debugging, the code is executed
        }

        var jQueryformValueProviderFactory = context.ValueProviderFactories.OfType<JQueryFormValueProviderFactory>().FirstOrDefault();
        if (jQueryformValueProviderFactory != null)
        {
            factories.RemoveType<JQueryFormValueProviderFactory>();
            //checked during debugging, the code is executed
        }
    }

    public void OnResourceExecuted(ResourceExecutedContext context)
    {
    }
}

In startup.cs i have adapted the Configure function for routing to my controller.

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    if (env.IsDevelopment())
    {
    app.UseDeveloperExceptionPage();
    }

    app.UseHttpsRedirection();

    app.UseUmbraco()
        .WithMiddleware(u =>
        {
        u.UseBackOffice();
        u.UseWebsite();
        })
        .WithEndpoints(u =>
        {
            // my routing start
            u.EndpointRouteBuilder.MapControllerRoute(
                "FileUpload",
                "/fileupload/{action}",
                new { Controller = "FileUpload", Action = "UploadToFilesystem" });
            // my routing end


            u.UseInstallerEndpoints();
            u.UseBackOfficeEndpoints();
            u.UseWebsiteEndpoints();
        });
}

does anyone have a tip for me?

Thanks Derek