ASP.NET MVC 4 FileResult - In error

Question

I have a simple Action on a controller which returns a PDF.

Works fine.

public FileResult GetReport(string id)
{
    byte[] fileBytes = _manager.GetReport(id);
    string fileName = id+ ".pdf";
    return File(fileBytes, MediaTypeNames.Application.Octet, fileName);
}

When the manager fails to get the report I get back null or an empty byte[].

How can I communicate to the browser that there was a problem, when the result is set to a FileResult?

Answer 1

I would change the return type of your method to ActionResult.

public ActionResult GetReport(string id)
{
    byte[] fileBytes = _manager.GetReport(id);
    if (fileBytes != null && fileBytes.Any()){
        string fileName = id+ ".pdf";
        return File(fileBytes, MediaTypeNames.Application.Octet, fileName);
    }
    else {
        //do whatever you want here
        return RedirectToAction("GetReportError");
    }
}

Answer 2

The FileResult class inherits from ActionResult. So, you can define your Action like this:

public ActionResult GetReport(string id)
{
    byte[] fileBytes = _manager.GetReport(id);
    string fileName = id + ".pdf";

    if(fileBytes == null || fileBytes.Length == 0)
       return View("Error");

    return File(fileBytes, MediaTypeNames.Application.Octet, fileName);
}