Changing response content type in asp.net Web API

Question

I have an asp.net Web Api controller with an Upload action. Here's the simplified version of the Upload action:

[HttpPost]
public async Task<string> Upload()
{            
    if (!Request.Content.IsMimeMultipartContent())
        throw new HttpResponseException(HttpStatusCode.UnsupportedMediaType);

    var provider = new MultipartMemoryStreamProvider();
    await Request.Content.ReadAsMultipartAsync(provider);
    var file = provider.Contents[0];

    try
    {
       // Save the file...
    }
    catch (Exception e)
    {
        return JsonConvert.SerializeObject(new
        {
            status = "error",
            message = e.Message
        });
    }

    return JsonConvert.SerializeObject(new
    {
        status = "success"
    });
}

The return type of the action has to be string, because it's used by a third-party upload widget that accepts serialized JSON only.

The problem is when I use this in IE 9, the browser doesn't accept application/json as a media type. So, I'll have to make sure the server returns plain/text . How can I do that without changing the return type of the action to HttpResponseMessage ?

Answer 1

You can do something like this:

public async Task<JsonResult> Upload()
return Json(someData, "text/html");

Although another option to just return the json is post though an iFrame then it will not attempt to download the returning html.