TDAmeritrade SignIn Unity3d / DotNet / C#

TDClientAlpha.cs

using System;
using System.Collections;
using System.Collections.Generic;
using System.Web;
using UnityEngine;
using UnityEngine.Networking;

namespace TDAmeritrade
{
    [Serializable]
    public class SignInResult
    {
        public string security_code;
        public string access_token;
        public string refresh_token;
        public string scope;
        public int expires_in;
        public int refresh_token_expires_in;
        public string token_type;
    }



    /// <summary>
    /// https://www.reddit.com/r/algotrading/comments/c81vzq/td_ameritrade_api_access_2019_guide/
    /// https://www.reddit.com/r/algotrading/comments/914q22/successful_access_to_td_ameritrade_api/
    /// </summary>
    public class TDClientAlpha : MonoBehaviour
    {
        public string ConsumerKey = "";
        public string RedirectUri = "http://localhost";
        [Header("Paste from code={code} address bar result in step 1")]
        public string SecurityCode = "";

        public SignInResult Result;

        private void Awake()
        {
            SecurityCode = string.Empty;
            Load();
        }

        private void Load()
        {
            Result = JsonUtility.FromJson<SignInResult>(PlayerPrefs.GetString("TDClientAlpha.SignInResult"));
        }

        private void Save()
        {
            var json = JsonUtility.ToJson(Result);
            PlayerPrefs.SetString("TDClientAlpha.SignInResult", json);
            PlayerPrefs.Save();
        }

        [ContextMenu("1 StartSignIn")]
        public void StartSignIn()
        {
            var encodedKey = HttpUtility.UrlEncode(ConsumerKey);
            var encodedUri = HttpUtility.UrlEncode(RedirectUri);
            var path = $"https://auth.tdameritrade.com/auth?response_type=code&redirect_uri={encodedUri}&client_id={encodedKey}%40AMER.OAUTHAP";
            Application.OpenURL(path);
        }

        [ContextMenu("2 CompleteSignIn")]
        public void CompleteSignIn()
        {
            StartCoroutine(CompleteSignInAsync());
        }

        IEnumerator CompleteSignInAsync()
        {

            var decoded = HttpUtility.UrlDecode(SecurityCode);
            var path = "https://api.tdameritrade.com/v1/oauth2/token";

            WWWForm form = new WWWForm();
            form.AddField("grant_type", "authorization_code");
            form.AddField("access_type", "offline");
            form.AddField("client_id", $"{ConsumerKey}@AMER.OAUTHAP");
            form.AddField("redirect_uri", RedirectUri);
            form.AddField("code", decoded);

            var webRequest = UnityWebRequest.Post(path, form);

            yield return webRequest.SendWebRequest();

            switch (webRequest.result)
            {
                case UnityWebRequest.Result.ConnectionError:
                case UnityWebRequest.Result.DataProcessingError:
                    Debug.LogError("Error: " + webRequest.error);
                    break;
                case UnityWebRequest.Result.ProtocolError:
                    Debug.LogError("HTTP Error: " + webRequest.error);
                    break;
                case UnityWebRequest.Result.Success:
                    var r = webRequest.downloadHandler.text;
                    Debug.Log(r);
                    Debug.LogWarning("HTTP Success, Received Access Token");
                    Result = JsonUtility.FromJson<SignInResult>(r);
                    Result.security_code = SecurityCode;
                    Save();
                    break;
            }
        }

        [ContextMenu("3 RefreshSignIn")]
        public void RefreshSignIn()
        {
            StartCoroutine(RefreshSignInAsync());
        }
        IEnumerator RefreshSignInAsync()
        {
            var decoded = HttpUtility.UrlDecode(Result.security_code);

            var path = "https://api.tdameritrade.com/v1/oauth2/token";

            WWWForm form = new WWWForm();
            form.AddField("grant_type", "refresh_token");
            form.AddField("access_type", "");
            form.AddField("client_id", $"{ConsumerKey}@AMER.OAUTHAP");
            form.AddField("redirect_uri", RedirectUri);
            form.AddField("refresh_token", Result.refresh_token);
            form.AddField("code", decoded);

            var webRequest = UnityWebRequest.Post(path, form);

            yield return webRequest.SendWebRequest();

            switch (webRequest.result)
            {
                case UnityWebRequest.Result.ConnectionError:
                case UnityWebRequest.Result.DataProcessingError:
                    Debug.LogError("Error: " + webRequest.error);
                    break;
                case UnityWebRequest.Result.ProtocolError:
                    Debug.LogError("HTTP Error: " + webRequest.error);
                    break;
                case UnityWebRequest.Result.Success:
                    var r = webRequest.downloadHandler.text;
                    Debug.Log(r);
                    var better = JsonUtility.FromJson<SignInResult>(r);
                    Result.access_token = better.access_token;
                    Save();
                    Debug.LogWarning("HTTP Success, Refreshed Access Token");
                    break;
            }
        }

        [ContextMenu("GetQuote")]
        public void GetQuote()
        {
            StartCoroutine(GetQuoteAsync());
        }
        IEnumerator GetQuoteAsync()
        {
            var symbol = "SPY";
            var key = HttpUtility.UrlEncode(ConsumerKey);

            var path = $"https://api.tdameritrade.com/v1/marketdata/{symbol}/quotes?apikey={key}";

            var webRequest = UnityWebRequest.Get(path);

            yield return webRequest.SendWebRequest();

            switch (webRequest.result)
            {
                case UnityWebRequest.Result.ConnectionError:
                case UnityWebRequest.Result.DataProcessingError:
                    Debug.LogError("Error: " + webRequest.error);
                    break;
                case UnityWebRequest.Result.ProtocolError:
                    Debug.LogError("HTTP Error: " + webRequest.error);
                    break;
                case UnityWebRequest.Result.Success:
                    var r = webRequest.downloadHandler.text;
                    Debug.Log(r);
                    Debug.LogWarning("HTTP Success, GetQuote");
                    break;
            }
        }
    }
}