added cache pipelines

NzbDrone.Api/Extensions/Pipelines/GZipPipeline.cs

@@ -0,0 +1,48 @@
+using System.IO;
+using System.IO.Compression;
+using System.Linq;
+using Nancy;
+using Nancy.Bootstrapper;
+
+namespace NzbDrone.Api.Extensions.Pipelines
+{
+    public class GzipCompressionPipeline : IRegisterNancyPipeline
+    {
+        public void Register(IPipelines pipelines)
+        {
+            pipelines.AfterRequest.AddItemToEndOfPipeline(c => CompressResponse(c.Request, c.Response));
+        }
+
+        private Response CompressResponse(Request request, Response response)
+        {
+            if (!response.ContentType.Contains("image")
+                && request.Headers.AcceptEncoding.Any(x => x.Contains("gzip"))
+                && (!response.Headers.ContainsKey("Content-Encoding") || response.Headers["Content-Encoding"] != "gzip"))
+            {
+                var data = new MemoryStream();
+                response.Contents.Invoke(data);
+                data.Position = 0;
+                if (data.Length < 1024)
+                {
+                    response.Contents = stream =>
+                    {
+                        data.CopyTo(stream);
+                        stream.Flush();
+                    };
+                }
+                else
+                {
+                    response.Headers["Content-Encoding"] = "gzip";
+                    response.Contents = s =>
+                    {
+                        var gzip = new GZipStream(s, CompressionMode.Compress, true);
+                        data.CopyTo(gzip);
+                        gzip.Close();
+                    };
+                }
+            }
+
+            return response;
+        }
+    }
+}