netmash/infrastructure/NDB.Infrastructure.PublicIP/Services/PublicIPService.cs

using Netmash.Infrastructure.PublicIP.Entities;
using Newtonsoft.Json;
using System.Net.Http;
using System.Threading.Tasks;

namespace Netmash.Infrastructure.PublicIP.Services
{
    public class PublicIPService : IPublicIPService
    {
        private const string _url1 = "https://api.ipify.org/?format=json";
        private const string _url2 = "https://ip.seeip.org/json";

        private readonly HttpClient _httpClient;

        public PublicIPService(HttpClient httpClient)
        {
            _httpClient = httpClient;
        }

        public async Task<IPInfo> GetPublicIP()
        {
            IPInfo result = null;

            using (var response = await _httpClient.GetAsync(_url1))
            {
                if (response.IsSuccessStatusCode)
                    result = await GetResult(response);
            }

            if (result != null)
                return result;

            using (var response = await _httpClient.GetAsync(_url2))
            {
                if (response.IsSuccessStatusCode)
                    result = await GetResult(response);
            }

            return result;
        }

        private async Task<IPInfo> GetResult(HttpResponseMessage response) => JsonConvert.DeserializeObject<IPInfo>(await response.Content.ReadAsStringAsync());
    }
}