Null Reference in TypeMatchFilter Middleware with non-JADNC Controller

[joshhubers]

Description

I'm getting a

    System.NullReferenceException: Object reference not set to an instance of an object.
    at JsonApiDotNetCore.Middleware.TypeMatchFilter.OnActionExecuting(ActionExecutingContext context) in 
C:\projects\jsonapidotnetcore\src\JsonApiDotNetCore\Middleware\TypeMatchFilter.cs:line 34

Using a standard dotnet Core Controller when returning a Json(result) of type string.
My code is as follows:

namespace Foo.Controllers
{
    [Authorize]
  public class UploadController : Controller
  {
    IPhotoService _photoService;

    public UploadController(IPhotoService photoService)
    {
      _photoService = photoService;
    }

    [Route("api/v1/attachments/upload")]
    [HttpPost]
    public async Task<IActionResult> PostFileAsync(IFormFile file)
    {
      if(file == null || file.Length == 0)
        return Content("No content in file or file not uploaded");

      string path = await _photoService.UploadPhotoAsync(file);
      
      return Json(path);
    }
  }
}

Looking at the code I'm gonna guess it's something to do with the IsJsonApiRequest not filtering replies properly?

Environment

• JsonApiDotNetCore Version: 2.5.2
• Other Relevant Package Versions:

[joshhubers]

Rolling back to 2.5.0 before the middleware update fixed the issue for me.

[jaredcnance]

Thanks for reporting this. Currently, we only check the Content-Type and assume that all application/vnd.api+json POST|PATCH requests should be handled by this filter. Are you using this content type in your non-json:api requests? We may be able to run a check against the activating controller type, but I'll need to verify that's possible.

Adding the source method for context:

JsonApiDotNetCore/src/JsonApiDotNetCore/Middleware/TypeMatchFilter.cs

Lines 22 to 45 in 491a6cb

	public void OnActionExecuting(ActionExecutingContext context)
	{
	var request = context.HttpContext.Request;
	if (IsJsonApiRequest(request) && request.Method == "PATCH" || request.Method == "POST")
	{
	var deserializedType = context.ActionArguments.FirstOrDefault().Value?.GetType();
	var targetType = context.ActionDescriptor.Parameters.FirstOrDefault()?.ParameterType;
	if (deserializedType != null && targetType != null && deserializedType != targetType)
	{
	var expectedJsonApiResource = _jsonApiContext.ContextGraph.GetContextEntity(targetType);
	throw new JsonApiException(409,
	$"Cannot '{context.HttpContext.Request.Method}' type '{_jsonApiContext.RequestEntity.EntityName}' "
	+ $"to '{expectedJsonApiResource?.EntityName}' endpoint.",
	detail: "Check that the request payload type matches the type expected by this endpoint.");
	}
	}
	}
	private bool IsJsonApiRequest(HttpRequest request)
	{
	return (request.ContentType?.Equals(Constants.ContentType, StringComparison.OrdinalIgnoreCase) == true);
	}

[joshhubers]

Yes, I am using the application/vnd.api+json content type. Good to know!

[medokin]

This bug was resolved with #457

Currently available in alpha.

[jaredcnance]

Thanks @medokin! Closing this. Please re-open if the issue is not resolved.