Generic repository style service for REST services

IJsonService<T>

  public interface IJsonService<T>
    {
        // Methods
        void Delete(T entity);
        IList<T> FindAll(IDictionary<string, object> propertyValuePairs, int pageNo, int resultsPerPage, string sortBy, string sortDirection);
        T Get(int id);
        IList<T> Get(List<int> IDs);
        IList<T> GetAll(int pageNo, int resultsPerPage, string sortBy, string sortDirection, string segment);
        RestResult Save(T entity);
        RestResult Update(T entity);
        IList<T> GetRelatedObjectsForEntity(string entityType, int entityId);

    }

IRestResource

 public interface IRestResource
    {
        int ID { get; set; }
    }

JsonService<T>

public class JsonService<T> : IJsonService<T> where T : IRestResource
    {
        private readonly string _serviceEndPoint = System.Configuration.ConfigurationManager.AppSettings["RestURL"];

        public void Delete(T entity)
        {
            throw new NotImplementedException();
        }


        /// <summary>
        /// Searches resources for instances that "start with" values in property keys
        /// </summary>
        /// <param name="propertyValuePairs">Dictionary of search keys / values - matches when "key" column starts with "value"</param>
        /// <param name="pageNo">page number </param>
        /// <param name="resultsPerPage">how many results per page</param>
        /// <param name="sortBy">column to sort by</param>
        /// <param name="sortDirection">direction (ASC || DESC)</param>
        /// <returns></returns>
        public IList<T> FindAll(IDictionary<string, object> propertyValuePairs, int pageNo, int resultsPerPage,
                                string sortBy, string sortDirection)
        {

            // Do we need to match on beginswith || equals || ends with???
            var matchtype = "beginswith";


            var searchString = "filter=";
            foreach (var p in propertyValuePairs)
            {
                searchString = String.Format("{0}{1}.{2}.{3}", searchString, p.Key,matchtype, p.Value);
            }

            var uri = String.Format("{0}/{5}/?offset={1}&limit={2}&sorttype={3}&sortby={4}&{6}",
                                    _serviceEndPoint, pageNo, resultsPerPage, sortDirection, sortBy, typeof (T).Name,
                                    searchString);

            string resp = GetJson(uri, HttpMethod.GET.ToString());
            var o = JObject.Parse(resp);
            var returnResources = o.SelectToken(typeof(T).Name + "s");
          

             var models = GetModels(returnResources);

            return models;
        }


        /// <summary>
        /// Return the full resource
        /// </summary>
        /// <param name="id">Id of the resource</param>
        /// <returns></returns>
        public T Get(int id)
        {
            // Grab the json feed from the service...
            var uri = String.Format("{0}/{1}/{2}", _serviceEndPoint, typeof (T).Name, id);
            var o = JObject.Parse(GetJson(uri, HttpMethod.GET.ToString()));
            var returnResource = o.SelectToken(typeof(T).Name + "s");

            // deserialise it for the view
            var models = GetModels(returnResource);
            return models[0];
        }


        public IList<T> Get(List<int> IDs)
        {
            var listOfIds = "";
            foreach(var i in IDs)
            {
                listOfIds += i.ToString() + ",";
            }

            var uri = String.Format("{0}/{1}/{2}", _serviceEndPoint, typeof(T).Name, listOfIds);
            var o = JObject.Parse(GetJson(uri, HttpMethod.GET.ToString()));
            var returnResources = o.SelectToken(typeof(T).Name + "s");

            var models = GetModels(returnResources);

            return models;
        }


        /// <summary>
        /// Get a list of resources
        /// </summary>
        /// <param name="pageNo">page number </param>
        /// <param name="resultsPerPage">how many results per page</param>
        /// <param name="sortBy">column to sort by</param>
        /// <param name="sortDirection">direction (ASC || DESC)</param>
        /// /// <param name="segment">name of segmented data (e.g. userwhohavenotloggedin)</param>
        /// <returns></returns>
        public IList<T> GetAll(int pageNo, int resultsPerPage, string sortBy, string sortDirection, string segment)
        {
            var uri = String.Format("{0}/{5}/?offset={1}&limit={2}&sorttype={3}&sortby={4}&segment={6}", _serviceEndPoint, pageNo,
                                    resultsPerPage, sortDirection, sortBy, typeof(T).Name, segment);
            var o = JObject.Parse(GetJson(uri, HttpMethod.GET.ToString()));

            var returnResources = o.SelectToken(typeof (T).Name + "s");

            var models = GetModels(returnResources);

            return models;
        }


        /// <summary>
        /// Save a new resource
        /// </summary>
        /// <param name="entity">the new resource</param>
        /// <returns>rest call result object</returns>
        public RestResult Save(T entity)
        {
            var restResult = PushJson(String.Format("{0}/{1}/", _serviceEndPoint, typeof (T).Name),
                                      HttpMethod.POST.ToString(), entity);

            return restResult;
        }


        /// <summary>
        /// Update a resource
        /// </summary>
        /// <param name="entity">the resource to persist</param>
        /// <returns>rest call result object</returns>
        public RestResult Update(T entity)
        {
            var restResult = PushJson(String.Format("{0}/{1}/{2}", _serviceEndPoint, typeof (T).Name, entity.ID),
                                      HttpMethod.PUT.ToString(), entity);

            return restResult;
        }


        /// <summary>
        /// Method for retrieving an objects related resources. 
        /// for example: UserAccount/1/UserGroups
        /// </summary>
        /// <param name="entityType">The name of the base entity - UserAccounts in the above example</param>
        /// <param name="entityId">The ID of the base entity</param>
        /// <returns>A list of objects related to the base entity</returns>
        public IList<T> GetRelatedObjectsForEntity(string entityType, int entityId)
        {
            var uri = String.Format("{0}/{1}/{2}/{3}s", _serviceEndPoint, entityType, entityId.ToString(), typeof(T).Name);
            var o = JObject.Parse(GetJson(uri, HttpMethod.GET.ToString()));

            var returnResources = o.SelectToken(typeof(T).Name + "s");

            var models = GetModels(returnResources);

            return models;
        }


        /// <summary>
        /// POST or PUT an object to the REST service
        /// </summary>
        /// <param name="uri">The URI of the resource</param>
        /// <param name="httpMethod"></param>
        /// <param name="entity"></param>
        /// <returns></returns>
        private RestResult PushJson(string uri, string httpMethod, T entity)
        {
            string json = Newtonsoft.Json.JsonConvert.SerializeObject(entity);
            byte[] arr = System.Text.Encoding.UTF8.GetBytes(json);
            var webRequest = GetWebRequest(String.Format("{0}/{1}/{2}", _serviceEndPoint, typeof (T).Name, entity.ID));
            webRequest.Method = httpMethod;
            webRequest.ContentType = "application/json";
            webRequest.ContentLength = arr.Length;
            Stream dataStream = webRequest.GetRequestStream();
            dataStream.Write(arr, 0, arr.Length);
            dataStream.Close();

            try
            {
                HttpWebResponse response = (HttpWebResponse)webRequest.GetResponse();

                // Service responses:
                string returnString = response.StatusCode.ToString();
                var jsonResult = new StreamReader(response.GetResponseStream()).ReadToEnd();
                var o = JArray.Parse(jsonResult);
                var restResult =
                    Newtonsoft.Json.JsonConvert.DeserializeObject<RestResult>(
                        o[0].ToString());

                foreach (JProperty j in o[0].SelectToken("Fields"))
                {
                    var f = new Field();
                    f.FieldName = j.Name;
                    f.Message = j.Value["Message"].ToString();
                    f.Status = j.Value["Status"].ToString();
                    restResult.Forms.Add(f);
                }


                return restResult;
            }
            catch (Exception e)
            {
                // Network down... What do we want to do?
                throw;
            }
        }


        private string GetJson(string uri, string httpMethod)
        {
            var webRequest = GetWebRequest(uri);
            webRequest.Method = httpMethod;
            webRequest.ContentType = "application/json";

            try
            {
                var response = (HttpWebResponse)webRequest.GetResponse();
                var jsonResponse = string.Empty;
                using (var sr = new StreamReader(response.GetResponseStream()))
                {
                    jsonResponse = sr.ReadToEnd();
                }
                return jsonResponse;
            }
            catch (Exception e)
            {
                // Network down... What do we want to do?
                throw;
            }
        }

        private static HttpWebRequest GetWebRequest(string formattedUri)
        {
            var serviceUri = new Uri(formattedUri, UriKind.Absolute);
            return (HttpWebRequest) System.Net.WebRequest.Create(serviceUri);
        }

        private List<T> GetModels(JToken returnResources)
        {
            List<T> models;
            if (returnResources == null || returnResources.Type == JTokenType.Null)
            {
                // There were no results in the list...
                return new List<T>();
            }
            if (returnResources.Type.ToString() == "Array")
            {
                models = Newtonsoft.Json.JsonConvert.DeserializeObject<List<T>>(returnResources.ToString());
            }
            else
            {
                // if there is only 1 result, the service does not return an array... we must serialise accordingly.
                models = new List<T>();
                models.Add(Newtonsoft.Json.JsonConvert.DeserializeObject<T>(returnResources.ToString()));
            }
            return models;
        }


     
    }

    public enum HttpMethod
    {
        GET = 1,
        POST = 2,
        PUT = 3,
        DELETE = 4
    }