POST方法JSON WebAPI请求失败，出现400错误请求

Question

I am new to ASP .net. I am trying to hit a webservice. The request type is GET. Using POST method and content type is JSON. I have used the online code and tried running. It always turn out to be bad request 400.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Web;
using System.Net;
using System.IO;
using System.Web.Script.Serialization;

namespace TestSuit_Get
{
    class Program
    {
        private const string URL = "http://10.33.20.54:8111/ucpData/customer/v1/getCustomer";

        private const string DATA = @"{""header"":{ ""messageId"":""123""},""body"":{ ""requestEntity"":{""productCode"":""002"", ""customerReferenceNumber"": 4010021421 }}}";
        static void Main(string[] args)
        {
            Program.CreateObject();
        }

        private static void CreateObject()
        {

            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(URL);
            request.Method = "POST";
            request.ContentType = "application/json";
           // request.ContentLength = DATA.Length;
            using (Stream webStream = request.GetRequestStream())
            using (StreamWriter requestWriter = new StreamWriter(webStream, System.Text.Encoding.ASCII))
            {

                JavaScriptSerializer json_serializer = new JavaScriptSerializer();
                Object routes_list =
                     json_serializer.DeserializeObject(DATA);
                requestWriter.Write(routes_list);
            }

            try
            {
                WebResponse webResponse = request.GetResponse();
                using (Stream webStream = webResponse.GetResponseStream() ?? Stream.Null)
                using (StreamReader responseReader = new StreamReader(webStream))
                {
                    string response = responseReader.ReadToEnd();
                    Console.Out.WriteLine(response);
                }
            }
            catch (Exception e)
            {
                Console.Out.WriteLine("-----------------");
                Console.Out.WriteLine(e.Message);
            }

        }
    }
}

Please help me in making it work. Next step would be instead passing this request manually i should be pass values dynamically with same template and get results of all GET requests.

Answer 1

Don't use the ancient HttpWebRequest , use HttpClient . Also, if a web service returns unexpected responses, use a debugging tool like Fiddler to inspect what exactly you're sending and receiving.

In this case, your requestWriter.Write(routes_list) will literally write the string System.Object to the request stream, which isn't what you want. You already have the JSON string you want to send, so why deserialize it into an object you then want to send?

Simply send the string:

requestWriter.Write(DATA);

And again, the code can be heavily simplified using the HttpClient .