EntityService.cs

using Newtonsoft.Json;
using RecordKeeper.Portable.Models;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Threading.Tasks;

namespace PortableClient.WebApi.Dal.Services
{
    public class EntityService<TEntity> where TEntity : EntityBase
    {
        protected static string API_BASE_PATH = "http://localhost:YOUR_PORT_HERE/api/";

        public EntityService() { }

        public static async Task<IEnumerable<TEntity>> Get(string apiPath, ICredentials credentials = null)
        {
            string uri = API_BASE_PATH + apiPath;
            HttpClientHandler handler = new HttpClientHandler();
            if (credentials != null)
            {
                handler.Credentials = credentials;
            }

            HttpClient client = new HttpClient(handler);

            string responseBody = await client.GetStringAsync(uri);

            List<TEntity> items = ListFromJson(responseBody);

            return items.AsEnumerable<TEntity>();
        }

        public static async Task<TEntity>Get(string apiPath, string id, ICredentials credentials = null)
        {
            string uri = API_BASE_PATH + apiPath + "/" + id;

            HttpClientHandler handler = new HttpClientHandler();
            if (credentials != null)
            {
                handler.Credentials = credentials;
            }

            HttpClient client = new HttpClient(handler);

            string responseBody = await client.GetStringAsync(uri);

            TEntity item = FromJson(responseBody);

            return item;
        }

        public static async void Update(string apiPath, TEntity entity, ICredentials credentials = null)
        {
            string uri = API_BASE_PATH + apiPath + "/" + entity.Id;

            HttpClientHandler handler = new HttpClientHandler();
            if (credentials != null)
            {
                handler.Credentials = credentials;
            }
            HttpClient client = new HttpClient(handler);

            // PUT the new entity on the server for an update
            var responseBody = await client.PutAsJsonAsync<TEntity>(uri, entity);

        }

        public static TEntity FromJson(string json)
        {
            TEntity entity;
            JsonSerializer s = new JsonSerializer();
            StringReader sr = new StringReader(json);
            JsonTextReader r = new JsonTextReader(sr);
            entity = s.Deserialize<TEntity>(r);
            return entity;
        }

        public static List<TEntity> ListFromJson(string json)
        {
            List<TEntity> entityList;
            JsonSerializer s = new JsonSerializer();
            StringReader sr = new StringReader(json);
            JsonTextReader r = new JsonTextReader(sr);
            entityList = s.Deserialize<List<TEntity>>(r);
            return entityList;
        }
    }
}