how to handle bad request exception in flurl

Question

I am totally new to Flurl.I am trying to call api and i deliberately passed invalid apikey in paramter and then api fails saying "Forbidden" and with error code 403. How can i handle that in Exception?

 public async Task<myResponse> MyService(myRequest request)
    {
        try
        {


            return await new Flurl.Url("https://myapi.com/rest/age?apikey=XXXXXXXX").PostJsonAsync(apirequest).ReceiveJson<myResponse>();
        }
        catch (FlurlHttpException ex)
        {
            var statusCode = await ex.GetResponseJsonAsync<myResponse>();
            return await ex.GetResponseJsonAsync<myResponse>();

        }

I want to throw my own custom exception if i get status code 403 but currently it fails on line var statusCode = await ex.GetResponseJsonAsync<myResponse>(); }

Answer 1

I want to throw my own custom exception if i get status code 403

There's 2 ways to do this. The first is to simply rethrow from a catch block (catch/when is handy here):

try
{
    ...
}
catch (FlurlHttpException ex) when (ex.Call.HttpStatus == HttpStatusCode.Forbidden)
{
    throw new MyException(...);
}

The second way is to prevent Flurl from throwing by using AllowHttpStatus:

var resp = await "https://myapi.com/rest/age?apikey=XXXXXXXX"
    .AllowHttpStatus("4xx")
    .PostJsonAsync(apirequest);

if (resp.StatusCode == HttpStatusCode.Forbidden)
{
    throw new MyException(...);
}

One caveat with the second approach is that you're left with a "raw" HttpResponseMessage that you'll need to deserialize yourself, since Flurl's ReceiveJson chains off a Task<HttpResponseMessage>, and you've already awaited that Task. But deserializing it yourself is not that hard, there's a planned enhancement that will address this in the near future, or you could always use this hacky little work-around:

await Task.FromResult(resp).ReceiveJson<myResponse>();

Honestly, I'd probably go with the first approach. FlurlHttpException has some handy methods like GetResponseJsonAsync<T> that allows you to deserialize the error body if it's JSON, or GetResponseStringAsync if you just need the raw string.