Jatin Sanghvi Jatin Sanghvi - 2 months ago 12
C# Question

Return a boolean from generic method for boolean return type

I have a generic method

SendHttpRequest<TRequest, TResponse>
that takes in a request-type and a response-type as its generic parameter inputs. The response-type can be either a boolean or a class representing the response.

My task is to return
true
if HTTP request made inside the method is successful and
TResponse
is a
bool
. If instead
TResponse
is of different type, I need to unserialize the response content into
TResponse
object. Returning
true
generates compile-time error. Is there a way to have a single method that supports both boolean and non-boolean return types?

private async Task<TResponse> SendHttpRequest<TRequest, TResponse>(TRequest request)
{
using (var client = new HttpClient())
{
client.BaseAddress = "http://example.com/";

var response = await client.PostAsJsonAsync("api_path", request).ConfigureAwait(false);

if (!response.IsSuccessStatusCode)
{
throw new MyException(response);
}

if (typeof (TResponse) == typeof (bool))
{
return true; // Generates compile-time error
}
else
{
var content = await response.Content.ReadAsStringAsync().ConfigureAwait(false);
return JsonConvert.DeserializeObject<TResponse>(content);
}
}
}

Evk Evk
Answer

I suppose you already understand that it's a bad design, but if you really want to make it exactly like this, you can do it:

private async Task<TResponse> SendHttpRequest<TRequest, TResponse>(TRequest request)
{
    using (var client = new HttpClient())
    {
        client.BaseAddress = "http://example.com/";

        var response = await client.PostAsJsonAsync("api_path", request).ConfigureAwait(false);

        if (!response.IsSuccessStatusCode)
        {
            throw new MyException(response);
        }

        if (typeof (TResponse) == typeof (bool))
        {
            return (TResponse)(object)true;
        }
        else
        {
            var content = await response.Content.ReadAsStringAsync().ConfigureAwait(false);
            return JsonConvert.DeserializeObject<TResponse>(content);
        }
    }
} 
Comments