c# HttpClient, how to get request with generic model parameter?

Question

I am using HttpClient for get and post request to my WebAPI. But I'm using generic Get.

My problem is how can I bind T generic object to GetAsync method?

Example, in my POST request I can use generic T like this:

public async Task<TResponse> Post<TRequest, TResponse>(TRequest request, string urlToSend)
    {
        try
        {
            using (HttpClient httpClient = new HttpClient())
            {
                httpClient.BaseAddress = new Uri(_url);
                var serialized = new StringContent(JsonConvert.SerializeObject(request), Encoding.UTF8, "application/json");
                var httpResponseMessage = await httpClient.PostAsync(urlToSend, serialized);
                //httpResponseMessage.EnsureSuccessStatusCode();
                if (httpResponseMessage.IsSuccessStatusCode)
                {
                    //var responseResultRaw = httpResponseMessage.Content.ReadAsStringAsync().Result;
                    var responseString = JsonConvert.DeserializeObject<TResponse>(httpResponseMessage.Content.ReadAsStringAsync().Result);

                    return responseString;
                }
                else /*if (httpResponseMessage.StatusCode == System.Net.HttpStatusCode.BadRequest)*/
                {
                    var errorRes = JsonConvert.DeserializeObject<TResponse>(httpResponseMessage.Content.ReadAsStringAsync().Result);
                    return errorRes;
                }
                throw new Exception(httpResponseMessage.ReasonPhrase);
            }
        }
        catch (Exception e)
        {
            return default;
        }
    }

But i did not found any example of how can I insert my generic TRequest to GetAsync().

Here is my code:

public async Task<TResponse> GetByFilter(TRequest request, string urlToRequest)
    {
        using (HttpClient client = new HttpClient())
        {
            client.BaseAddress = new Uri(_url);
            var response = await client.GetAsync(urlToRequest);
            var responseString = await response.Content.ReadAsStringAsync();
            var responseJson = JsonConvert.DeserializeObject<TResponse>(responseString);
            return responseJson;
        }

        throw new NotImplementedException();
    }

Simply, my question is can i use a model in GetAsync() method like httpClient.PostAsync(urlToSend, serialized);

My API controller method is like this:

[HttpGet("getfirmdetail")]
    public IActionResult GetFirmDetail([FromBody]FirmDetailRequestDto firmDetailRequestDto)
    {

        return BadRequest(firmDetailRequestDto);
    }

Answer 1

The GET requests doesn't have a body, so you have to pass all the parameters in the URL, in your example the attribute urlToRequest.

Otherwise if you are using NET Core you can go with:

public async Task<TResponse> GetByFilter(TRequest request, string urlToRequest)
    {
        using (HttpClient client = new HttpClient())
        {
            var jsonBody= Newtonsoft.Json.JsonConvert.SerializeObject(request)
            var requestGet = new HttpRequestMessage
           {
              Method = HttpMethod.Get,
              RequestUri = new Uri(urlToRequest),
              Content = new StringContent(jsonBody, Encoding.UTF8, ContentType.Json),
           };
            var resp = await client.SendAsync(requestGet).ConfigureAwait(false);
            var responseString = await resp.Content.ReadAsStringAsync().ConfigureAwait(false);
            var responseJson = JsonConvert.DeserializeObject<TResponse>(responseString);
            return responseJson;
        }
    }

Answer 2

With a Get request there is no body to put the serialized 'request' in. You could put the serialized 'request' in a querystring parameter but there are limitations to the total length of an Url. If you can, always use Post.