HttpProvider.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Net;
using System.Net.Http;
using System.Net.Http.Headers;
using Newtonsoft.Json;

namespace iMovies.Api
{
    public class HttpProvider
    {
        private static HttpClient client;
        private static HttpResponseHeaders responseHeaders;

        public static async Task<string> Post(string url, Dictionary<string, string> parameters)
        {
            client = new HttpClient();
            BeforeRequest();
            FormUrlEncodedContent form = new FormUrlEncodedContent(parameters);
            HttpResponseMessage resp = await client.PostAsync(url, form);
            responseHeaders = resp.Headers;
            string content = await resp.Content.ReadAsStringAsync();
            AfterRequest(content);
            return content;
        }

        public static async Task<string> Get(string url)
        {
            client = new HttpClient();
            BeforeRequest();
            HttpResponseMessage resp = await client.GetAsync(url);
            responseHeaders = resp.Headers;
            string content = await resp.Content.ReadAsStringAsync();
            AfterRequest(content);
            return content;
        }

        private static void BeforeRequest()
        {
            if (!string.IsNullOrEmpty(Config.Token))
            {
                client.DefaultRequestHeaders.Add("Authorization", "Bearer " + Config.Token);
            }
        }

        private static void AfterRequest(string response)
        {
            if (responseHeaders.Contains("Authorization"))
            {
                string token = responseHeaders.GetValues("Authorization").FirstOrDefault();
                if (!string.IsNullOrEmpty(token))
                {
                    Config.OldToken = Config.Token;
                    Config.Token = token.TrimStart("Bearer".ToCharArray());
                }
            }
            JsonError error = JsonConvert.DeserializeObject<JsonError>(response);
            if (error.Error) {
                if(error.Message.Contains("token") || error.Error.Contains("token")) {
                    throw new RequiredAuthException();
                } else {
                    throw new Exception(error.Message);
                }
            }
        }
    }

    public class JsonError
    {
        public string Error { get; set; }
        public string Message { get; set; }
        public JsonError(bool error, string message)
        {
            this.Error = error;
            this.Message = message;
        }
    }
}