Make string cache configurable

Author: benaadams

src/Microsoft.AspNet.Server.Kestrel/Http/Frame.cs

@@ -70,23 +70,25 @@ public abstract partial class Frame : FrameContext, IFrameControl
         private readonly Action<IFeatureCollection> _prepareRequest;
 
         private readonly string _pathBase;
-        protected readonly IStringCache _stringCache = new StringCache();
+        protected readonly IStringCache _stringCache;
 
         public Frame(ConnectionContext context)
-            : this(context, remoteEndPoint: null, localEndPoint: null, prepareRequest: null)
+            : this(context, remoteEndPoint: null, localEndPoint: null, prepareRequest: null, stringCache: null)
         {
         }
 
         public Frame(ConnectionContext context,
                      IPEndPoint remoteEndPoint,
                      IPEndPoint localEndPoint,
-                     Action<IFeatureCollection> prepareRequest)
+                     Action<IFeatureCollection> prepareRequest,
+                     IStringCache stringCache)
             : base(context)
         {
             _remoteEndPoint = remoteEndPoint;
             _localEndPoint = localEndPoint;
             _prepareRequest = prepareRequest;
             _pathBase = context.ServerAddress.PathBase;
+            _stringCache = stringCache;
 
             FrameControl = this;
             Reset();

src/Microsoft.AspNet.Server.Kestrel/Http/FrameOfT.cs

@@ -6,6 +6,7 @@
 using System.Threading.Tasks;
 using Microsoft.AspNet.Hosting.Server;
 using Microsoft.AspNet.Http.Features;
+using Microsoft.AspNet.Server.Kestrel.Infrastructure;
 using Microsoft.Extensions.Logging;
 
 namespace Microsoft.AspNet.Server.Kestrel.Http
@@ -16,16 +17,17 @@ public class Frame<TContext> : Frame
 
         public Frame(IHttpApplication<TContext> application,
                      ConnectionContext context)
-            : this(application, context, remoteEndPoint: null, localEndPoint: null, prepareRequest: null)
+            : this(application, context, remoteEndPoint: null, localEndPoint: null, prepareRequest: null, stringCache: null)
         {
         }
 
         public Frame(IHttpApplication<TContext> application,
                      ConnectionContext context,
                      IPEndPoint remoteEndPoint,
                      IPEndPoint localEndPoint,
-                     Action<IFeatureCollection> prepareRequest)
-            : base(context, remoteEndPoint, localEndPoint, prepareRequest)
+                     Action<IFeatureCollection> prepareRequest,
+                     IStringCache stringCache)
+            : base(context, remoteEndPoint, localEndPoint, prepareRequest, stringCache)
         {
             _application = application;
         }

src/Microsoft.AspNet.Server.Kestrel/IKestrelServerInformation.cs

@@ -11,6 +11,12 @@ public interface IKestrelServerInformation
 
         bool NoDelay { get; set; }
 
+        bool StringCacheOnConnection { get; set; }
+
+        int StringCacheMaxStrings { get; set; }
+
+        int StringCacheMaxStringLength { get; set; }
+
         IConnectionFilter ConnectionFilter { get; set; }
     }
 }

src/Microsoft.AspNet.Server.Kestrel/KestrelServer.cs

@@ -60,7 +60,15 @@ public void Start<TContext>(IHttpApplication<TContext> application)
                 {
                     FrameFactory = (context, remoteEP, localEP, prepareRequest) => 
                     {
-                        return new Frame<TContext>(application, context, remoteEP, localEP, prepareRequest);
+                        return new Frame<TContext>(
+                            application, 
+                            context, 
+                            remoteEP, 
+                            localEP, 
+                            prepareRequest, 
+                            information.StringCacheOnConnection ? 
+                                new StringCache(information.StringCacheMaxStrings, information.StringCacheMaxStringLength) : 
+                                null);
                     },
                     AppLifetime = _applicationLifetime,
                     Log = trace,

src/Microsoft.AspNet.Server.Kestrel/KestrelServerInformation.cs

@@ -16,6 +16,8 @@ public KestrelServerInformation(IConfiguration configuration, int threadCount)
             Addresses = GetAddresses(configuration);
             ThreadCount = threadCount;
             NoDelay = true;
+
+            ConfigureStringCache(configuration);
         }
 
         public ICollection<string> Addresses { get; }
@@ -24,6 +26,12 @@ public KestrelServerInformation(IConfiguration configuration, int threadCount)
 
         public bool NoDelay { get; set; }
 
+        public bool StringCacheOnConnection { get; set; }
+
+        public int StringCacheMaxStrings { get; set; }
+
+        public int StringCacheMaxStringLength { get; set; }
+
         public IConnectionFilter ConnectionFilter { get; set; }
 
         private static ICollection<string> GetAddresses(IConfiguration configuration)
@@ -39,5 +47,48 @@ private static ICollection<string> GetAddresses(IConfiguration configuration)
 
             return addresses;
         }
+
+        private void ConfigureStringCache(IConfiguration configuration)
+        {
+            bool stringCacheOnConnection;
+            if (bool.TryParse(configuration["server.stringCacheOnConnection"], out stringCacheOnConnection))
+            {
+                StringCacheOnConnection = stringCacheOnConnection;
+            }
+            else
+            {
+                StringCacheOnConnection = true;
+            }
+            int stringCacheMaxStrings;
+            if (stringCacheOnConnection && int.TryParse(configuration["server.stringCacheMaxStrings"], out stringCacheMaxStrings))
+            {
+                if (stringCacheMaxStrings <= 0)
+                {
+                    throw new ArgumentOutOfRangeException(nameof(stringCacheMaxStrings),
+                        stringCacheMaxStrings,
+                        "StringCacheMaxStrings must be positive.");
+                }
+                StringCacheMaxStrings = stringCacheMaxStrings;
+            }
+            else
+            {
+                StringCacheMaxStrings = 25;
+            }
+            int stringCacheMaxStringLength;
+            if (stringCacheOnConnection && int.TryParse(configuration["server.stringCacheMaxStringLength"], out stringCacheMaxStringLength))
+            {
+                if (stringCacheMaxStringLength <= 0)
+                {
+                    throw new ArgumentOutOfRangeException(nameof(stringCacheMaxStringLength),
+                        stringCacheMaxStringLength,
+                        "StringCacheMaxStringLength must be positive.");
+                }
+                StringCacheMaxStringLength = stringCacheMaxStringLength;
+            }
+            else
+            {
+                StringCacheMaxStringLength = 256;
+            }
+        }
     }
 }

test/Microsoft.AspNet.Server.KestrelTests/TestServer.cs

@@ -35,7 +35,7 @@ public void Create(RequestDelegate app, ServiceContext context, string serverAdd
         {
             context.FrameFactory = (connectionContext, remoteEP, localEP, prepareRequest) => 
             {
-                return new Frame<HttpContext>(new DummyApplication(app), connectionContext, remoteEP, localEP, prepareRequest);
+                return new Frame<HttpContext>(new DummyApplication(app), connectionContext, remoteEP, localEP, prepareRequest, stringCache: null);
             };
             _engine = new KestrelEngine(context);
             _engine.Start(1);

test/Microsoft.AspNet.Server.KestrelTests/TestServiceContext.cs

@@ -31,7 +31,7 @@ public RequestDelegate App
                 _app = value;
                 FrameFactory = (connectionContext, remoteEP, localEP, prepareRequest) =>
                 {
-                    return new Frame<HttpContext>(new DummyApplication(_app), connectionContext, remoteEP, localEP, prepareRequest);
+                    return new Frame<HttpContext>(new DummyApplication(_app), connectionContext, remoteEP, localEP, prepareRequest, new StringCache(25, 256));
                 };
             }
         }