gistfile1.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Text;
using System.Threading.Tasks;
using RestSharp;

namespace Fluxmatix.Authentication
{
    public class EmailOctopusUserEmailDataExporter : IUserEmailDataExporter
    {
        public static string ApiKey { get; set; }

        public void Export(IUser user, object listIdentifier)
        {
            var listId = (string)listIdentifier;
            var rest = new RestClient("https://emailoctopus.com/api/1/");
            var req = new RestRequest(string.Format("lists/{0}/members", listId));
            var data = new EmailOctopusRequestData() {
                api_key = ApiKey,
                email_address = user.Email,
                first_name = user.Username,
                last_name = "",
                subscribed = true
            };
            req.AddBody(data);
            req.Method = Method.POST;
            var response = rest.Execute<EmailOctopusReponseData>(req);
        }
    }

    public class EmailOctopusRequestData
    {
        public string api_key { get; set; }
        public string email_address { get; set; }
        public string first_name { get; set; }
        public string last_name { get; set; }
        public bool subscribed { get; set; }
    }

    public class EmailOctopusReponseData
    {
        public Member member { get; set; }
    }

    public class Member
    {
        public string id { get; set; }
        public string email_address { get; set; }
        public string first_name { get; set; }
        public string last_name { get; set; }
        public bool subscribed { get; set; }
        public DateTime created_at { get; set; }
    }
}