Extends the HttpRequestMessage collection

HttpRequestMessageExtensions.cs

using System.Collections.Generic;
using System.Linq;
using System.Net.Http;
using System.Net.Http.Headers;
namespace System.Web.Http {
  /// <summary>
  /// Extends the HttpRequestMessage collection
  /// </summary>
  /// <remarks>http://weblog.west-wind.com/posts/2013/Apr/15/WebAPI-Getting-Headers-QueryString-and-Cookie-Values</remarks>
  public static class HttpRequestMessageExtensions {
    /// <summary>
    /// Returns a dictionary of QueryStrings that's easier to work with 
    /// than GetQueryNameValuePairs KevValuePairs collection.
    /// 
    /// If you need to pull a few single values use GetQueryString instead.
    /// </summary>
    /// <param name="request"></param>
    /// <returns></returns>
    public static Dictionary<string, string> GetQueryStrings(this HttpRequestMessage request) {
      return request.GetQueryNameValuePairs()
                    .ToDictionary(kv => kv.Key, kv => kv.Value, StringComparer.OrdinalIgnoreCase);
    }

    /// <summary>
    /// Returns raw string of QueryStrings
    /// </summary>
    /// <param name="request"></param>
    /// <returns></returns>
    public static string GetRawQueryString(this HttpRequestMessage request) {
      var items = new List<string>();
      request.GetQueryNameValuePairs().ToList().ForEach(it => {
        items.Add(string.Concat(it.Key, "=", Uri.EscapeDataString(it.Value)));
      });
      return items.Count == 0 ? string.Empty : string.Join("&", items.ToArray());
    }

    /// <summary>
    /// Returns an individual querystring value
    /// </summary>
    /// <param name="request"></param>
    /// <param name="key"></param>
    /// <returns></returns>
    public static string GetQueryString(this HttpRequestMessage request, string key) {
      // IEnumerable<KeyValuePair<string,string>> - right!
      var queryStrings = request.GetQueryNameValuePairs();
      if (queryStrings == null)
        return null;

      var match = queryStrings.FirstOrDefault(kv => string.Compare(kv.Key, key, true) == 0);
      if (string.IsNullOrEmpty(match.Value))
        return null;

      return match.Value;
    }

    /// <summary>
    /// Returns an individual HTTP Header value
    /// </summary>
    /// <param name="request"></param>
    /// <param name="key"></param>
    /// <returns></returns>
    public static string GetHeader(this HttpRequestMessage request, string key) {
      IEnumerable<string> keys = null;
      if (!request.Headers.TryGetValues(key, out keys))
        return null;

      return keys.First();
    }

    /// <summary>
    /// Retrieves an individual cookie from the cookies collection
    /// </summary>
    /// <param name="request"></param>
    /// <param name="cookieName"></param>
    /// <returns></returns>
    public static string GetCookie(this HttpRequestMessage request, string cookieName) {
      CookieHeaderValue cookie = request.Headers.GetCookies(cookieName).FirstOrDefault();
      if (cookie != null)
        return cookie[cookieName].Value;

      return null;
    }
  }
}