ASP.NET Web API RSS Feed Controller

FeedController.cs

using Newtonsoft.Json.Linq;
using Songhay.Extensions;
using Songhay.Web.Extensions;
using System;
using System.Collections.Generic;
using System.Configuration;
using System.IO;
using System.Linq;
using System.ServiceModel.Syndication;
using System.Web.Http;
using System.Xml;

namespace Songhay.Dashboard.Controllers
{
    /// <summary>
    /// <see cref="SyndicationFeed"/> Controller
    /// </summary>
    /// <seealso cref="ApiController" />
    [RoutePrefix("api")]
    public class FeedController : ApiController
    {
        /// <summary>
        /// Initializes a new instance of the <see cref="FeedController"/> class.
        /// </summary>
        public FeedController()
        {
            var feedsPath = ConfigurationManager.AppSettings.GetPathFromAppSettings("SyndicationFeeds", typeof(Global));
            var jO = JObject.Parse(File.ReadAllText(feedsPath));
            this._feeds = jO.GetDictionary("feeds");
        }

        /// <summary>
        /// Gets the feed.
        /// </summary>
        /// <param name="id">The identifier.</param>
        /// <returns></returns>
        /// <exception cref="System.NullReferenceException">The expected Syndication feeds are not here.</exception>
        /// <exception cref="System.IndexOutOfRangeException">The expected feed key is not here.</exception>
        [Route("feed/{id}")]
        public SyndicationFeed GetFeed(string id)
        {
            if (this._feeds == null) throw new NullReferenceException("The expected Syndication feeds are not here.");
            if (!this._feeds.Keys.Contains(id)) throw new IndexOutOfRangeException("The expected feed key is not here.");
            var feedUri = new Uri(this._feeds[id]);

            SyndicationFeed feed;
            using (var reader = XmlReader.Create(feedUri.AbsoluteUri))
            {
                feed = SyndicationFeed.Load(reader);
            }

            return feed;
        }

        Dictionary<string, string> _feeds;
    }
}

SyndicationFeeds.json

{
    "feeds": {
        "codepen": "http://codepen.io/rasx/public/feed/",
        "flickr": "http://api.flickr.com/services/feeds/photoset.gne?set=72157625087343217&nsid=7160940@N02&format=rss2&lang=en-us",
        "studio": "http://songhayblog.azurewebsites.net/feed?formatter=rss"
    }
}