How to post JSON data from ASP.Net MVC controller?

Question

I am building an ASP.Net MVC web application which will be a portal for a secured device. This device supports JSON API. I tried developing client side (angularJS scripts with $httpProvider methods to post and get data) but fallen into the problem of CORS.

What I want to do is: The web app server will post and get the requests then they will be redirected as simple HTML to the client.

The problem is how can I execute a HTTP request from my controller to this device.

This question has one answer which is not clear.

To note I tried using HTTPWebRequest in the controller but the namespace System.Net.HTTP.WebRequest would not be included even though it is in the references of my project.

Edit: Attempts so far: This is the Account Model:

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
using System.Data.Entity;
using System.Globalization;
using System.Web.Security;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Threading.Tasks;

namespace Project1.Models
{
    public class LoginModel
    {
        [Required]
        [Display(Name = "User name")]
        public string UserName { get; set; }

        [Required]
        [DataType(DataType.Password)]
        [Display(Name = "Password")]
        public string Password { get; set; }




        internal System.Web.Mvc.ActionResult PostJson(LoginModel model, StringContent query)
        {
            throw new NotImplementedException();
        }
    }
}

And this is the controller:

    using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using System.Transactions;
using System.Web;
using System.Web.Mvc;
using Newtonsoft;
using System.Web.Security;
using DotNetOpenAuth.AspNet;
using System.Net.Http;
using System.Net.Http.Headers;
using Microsoft.Web.WebPages.OAuth;
using WebMatrix.WebData;
using Project1.Models;

namespace Project1.Controllers
{
    [Authorize]
    public class AccountController : Controller
    {
        public async Task<ActionResult> PostJson(LoginModel model, StringContent data)
        {
            using (var client = new HttpClient())
            {
                client.BaseAddress = new Uri("http://localhost:1532/Account/Login");
                HttpResponseMessage response = await client.PostAsync("http://192.168.30.1/jsonrpc", data);
                if (response.IsSuccessStatusCode)
                {
                    Console.Write(response.ToString());

                }
                Console.Write(response.ToString());
                return View(model);

            }
        }

        //
        // GET: /Account/Login

        [AllowAnonymous]
        public ActionResult Login(string returnUrl)
        {
            ViewBag.ReturnUrl = returnUrl;
            return View();
        }

        //
        // POST: /Account/Login

        [HttpPost]
        [AllowAnonymous]
        [ValidateAntiForgeryToken]
        public ActionResult Login(LoginModel model, string returnUrl)
        {
            if (ModelState.IsValid)
            {
                var data ="{\"params\" : [{\"url\" : \"sys/login/user\",\"data\" : [{\"passwd\" :" + model.Password +",\"user\" :" + model.UserName + "}]}],\"session\" : 1,\"id\" : 1,\"method\" : \"exec\"}";
                StringContent query = new StringContent(data);
                return (model.PostJson(model,query));
            }

            // If we got this far, something failed, redisplay form
            ModelState.AddModelError("", "The user name or password provided is incorrect.");
            return View(model);
        }


        #region Helpers
        private ActionResult RedirectToLocal(string returnUrl)
        {
            if (Url.IsLocalUrl(returnUrl))
            {
                return Redirect(returnUrl);
            }
            else
            {
                return RedirectToAction("Index", "Home");
            }
        }
        #endregion
    }
}

@CallumLinington This seems like it would work. The problem is using POST and GET with the HttpClient causes some problems because the post and get are async and the controller is synchronized. — Yacine Ben Slimene
– Yacine Ben Slimene, Commented Mar 8, 2016 at 12:52
you have two options, public async Task<IActionResult> SomeAction() as your controller action or you can do client.PostAsync().Result. — Callum Linington
– Callum Linington, Commented Mar 8, 2016 at 13:24
@CallumLinington this raises a NotImplementedException for some reason that is beyond me. — Yacine Ben Slimene
– Yacine Ben Slimene, Commented Mar 8, 2016 at 15:09

Yacine Ben Slimene · Accepted Answer · 2016-03-29 13:29:53Z

After sending JSON with PostMan I was able to create classes for the JSON request as well as the response. All I had to do next, is add a class which I called Service. In this class, which has an integer and the url of the JSON server as attributes, I add all my functions to call the API. The integer represents the ID of the request and the url will be used in every function.

Now Here is what really matters. The following code is for making a Login using credentials from the remote device and sending user input in JSON data:

public Response Login(String usr, String pwd)
        {
            this.MyId++;
            Request model = new Request(id, usr, pwd);
            var http = (HttpWebRequest)WebRequest.Create(uri);
            http.Accept = "application/json";
            http.ContentType = "application/json";
            http.Method = "POST";
            String json = Newtonsoft.Json.JsonConvert.SerializeObject(model);
            UTF8Encoding encoding = new UTF8Encoding();
            Byte[] bytes = encoding.GetBytes(json);

            Stream newStream = http.GetRequestStream();
            newStream.Write(bytes, 0, bytes.Length);
            newStream.Close();

            var response = http.GetResponse();

            var stream = response.GetResponseStream();
            var sr = new StreamReader(stream);
            var content = sr.ReadToEnd();
            Response res= Newtonsoft.Json.JsonConvert.DeserializeObject<Response>(content.ToString());
            return res;

        }

As you notice here, we create an instance of a c# class called Request. This class is then serialized into JSON string. The JSON string is then put into the stream and sent with UTF-8 Encoding. Then we get the response and deserialize it into a c# class which with it we can know if the user was authenticated or not. Based on the result, we can redirect the client to his home page or prompt him to input a correct login and password.

PS This procedure is totally CORS free. And this way I send and receive data in my server and assess it then send HTML views accordingly. This keeps my requests and the remote device totally hidden.

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