async and await, capture exceptions when the Post is done. .

Question

User-1825561198 posted

            using (HttpClient client = new HttpClient())
            {
                       
                client.DefaultRequestHeaders.Clear();
                client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
                client.DefaultRequestHeaders.Add("X-SDS-User", "test");
               
                
                var json = JsonConvert.SerializeObject(MyRequest);

                HttpContent content = new StringContent(json, System.Text.Encoding.UTF8, "application/json");
                string StringAsync = string.Empty;
                try
                {
                    StringAsync = await client.PostAsync(_ServiceURL, content).Result.Content.ReadAsStringAsync();
                    Result = JsonConvert.DeserializeObject<RequestResult>(StringAsync);
                   return Result; 
                 }
                 catch(Exception)
                {
                }
            }

In my code I am using async await which is working perfectly. The only thing is I want to be able to catch the exceptions or messages through by my service.

How would I capture the Result as a HTTpResponseMessage?

Could we use PutAsJSonAsync , if so how would we use it. Please help with code. I am looking to capture if the service returns exceptions when the Post is done.

HttpResponseMessage response = await client.PutAsJsonAsync(_ServiceURL,);

This call to the service is made from a non web application.

Thank you

Answer 1

User-1946294156 posted

In the web api, I typically do this in the Catch section:

var resp = new HttpResponseMessage(HttpStatusCode.InternalServerError)
{
    ReasonPhrase = "Exception:" + exception.Message
};
throw new HttpResponseException(resp);

Any of Call Functions (Get, Post, Put, Delete) have a Try/Catch statement with the above nicely nested into the catch statement of the call.  As you can see, I only send the message back, you can send the entire exception back.  The web APIs that I have run on a server I have access to, so before I have this code, I drop the who exception into the event log of the server. 

 You would handle the exception like this on your client side code:

var response = httpClient.GetAsync("api/controller").Result;
if (response.IsSuccessStatusCode)
{
   IEnumerable<myClass> r = response.Content.ReadAsAsync<IEnumerable<myClass>>().Result;
   return r;
}

if (response.ReasonPhrase.Contains("Exception"))
{
   throw new Exception(response.ReasonPhrase.Substring(10, response.ReasonPhrase.Length - 10));
}

throw new Exception("No Response from Server.", new Exception(response.ReasonPhrase));

Answer 2

User-1825561198 posted

HttpContent content = new StringContent(json, System.Text.Encoding.UTF8, "application/json");
                string StringAsync = string.Empty;
                try
                {
                    HttpResponseMessage Response = client.PostAsync(_ServiceURL, content).Result;

                    if (Response.IsSuccessStatusCode)
                    {
                        StringAsync = await Response.Content.ReadAsStringAsync();
                        requestResult = JsonConvert.DeserializeObject<RequestResult>(StringAsync);

                    }
                    if (!Response.ReasonPhrase.Contains("OK") || requestResult == null)
                    {
                        throw new Exception(Response.ReasonPhrase.ToString());
                    }

                    return requestResult;
                }
                catch (Exception ex)
                {
                    
                }
                return requestResult;

This worked for me. Is there a better way in doing this?

Thank you for getting back.