How to configure .NET Core API to always return JSON

Question

I've created a .NET Core API. If I set the endpoint to return an object, it currently successfully returns it in JSON as desired. If the return type of the endpoint is void, however, it gives a 200 response, but the response header is text/html instead of application/json.

How can I configure my .NET Core API to always give a response with a JSON header?

Answer 1

You need to return JsonResult type, like

// GET: api/authors
[HttpGet]
public JsonResult Get()
{
    return Json(_authorRepository.List());
}

more is here

Answer 2

add a filter of type ProducesAttribute("application/json") to the ConfigureServices. In the Startup.cs

    public void ConfigureServices(IServiceCollection services)
    {
        services.AddMvc(options =>
            {
                options.Filters.Add(new ProducesAttribute("application/json"));
            });
    }