HttpClient PostAsync not responding when use in GenericHandler

Question

User1348063978 posted

Hi, 

I have a problem about using HttpClient PostAsync. Below sample code, I try to call restful service  from another one restful service. Both create in same asp.net site, the result is no responding but i can call target service manually(use browser) and i can use same code call target service from window console application. Any help?

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Data;
using System.Threading.Tasks;
using Newtonsoft.Json;
using System.Net.Http;
using System.Net;
using System.IO;

namespace Api
{
    /// <summary>
    /// Summary description for Gateway
    /// </summary>
    public class Gateway : IHttpHandler
    {
        public void ProcessRequest(HttpContext context)
        {
            try
            {
                RunAsync(context).Wait();
            }
            catch (Exception ex)
            {
                context.Response.Write(ex.Message);
            }
        }

        protected async Task RunAsync(HttpContext context)
        {
            SearchParameter parm = new SearchParameter();

            ApiResponse resp = await CallApi<ApiResponse>("http://localhost:50125/api/Test.ashx", parm);

            context.Response.ContentType = "text/javascript";
            context.Response.Write(JsonConvert.SerializeObject(resp));
        }

        public static async Task<T> CallApi<T>(string url, object reqData)
        {
            object ret = null;
            var jsonString = JsonConvert.SerializeObject(reqData);

            StringContent content = new StringContent(jsonString);
            HttpClient client = new HttpClient();

            HttpResponseMessage resp = await client.PostAsync(url, content);

            if (resp.StatusCode == HttpStatusCode.OK)
            {
                Stream stream = await resp.Content.ReadAsStreamAsync();
                StreamReader sr = new StreamReader(stream);
                string responseText = sr.ReadToEnd();
                sr.Dispose();

                try
                {
                    ret = JsonConvert.DeserializeObject<T>(responseText);
                }
                catch (Exception ex)
                {
                    throw new Exception("Invalid API response object.", ex);
                }
            }

            return (T)ret;
        }

        public bool IsReusable
        {
            get
            {
                return false;
            }
        }
    }

    public class ApiResponse
    {
        public string Code = "";
        public string Message = "";
        public string StackTrace = "";
        public string Api = "";
    }

    public class SearchParameter
    {
        public string SessionID = "0";
        public string Keyword = "";
    }
}

Answer 1

User475983607 posted

Have you tried setting a breakpoint and simply debugging the code?

The parm value is always empty.  Is that expected?

SearchParameter parm = new SearchParameter();

ApiResponse resp = await CallApi<ApiResponse>("http://localhost:50125/api/Test.ashx", parm);

Answer 2

User1348063978 posted

i just try to show sample code. The parameter is not meaning, Test.ashx will return static ApiReponse data.

Answer 3

User1348063978 posted

i tried to debug program until i found the line of problem, it is "PostAsync". This line will not responding,life time not responding, no error occurs.