Cache the ContentLength header value

Author: Tratcher

src/Microsoft.AspNetCore.Server.HttpSys/FeatureContext.cs

@@ -72,7 +72,7 @@ internal FeatureContext(RequestContext requestContext, bool enableResponseCachin
             _enableResponseCaching = enableResponseCaching;
 
             // Pre-initialize any fields that are not lazy at the lower level.
-            _requestHeaders = new HeaderDictionary(Request.Headers);
+            _requestHeaders = Request.Headers;
             _httpMethod = Request.Method;
             _path = Request.Path;
             _pathBase = Request.PathBase;
@@ -82,7 +82,7 @@ internal FeatureContext(RequestContext requestContext, bool enableResponseCachin
             _user = _requestContext.User;
 
             _responseStream = new ResponseStream(requestContext.Response.Body, OnStart);
-            _responseHeaders = new HeaderDictionary(Response.Headers);
+            _responseHeaders = Response.Headers;
         }
 
         internal IFeatureCollection Features => _features;

src/Microsoft.AspNetCore.Server.HttpSys/HeaderDictionary.cs

@@ -4,12 +4,17 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
+using Microsoft.AspNetCore.Http;
 using Microsoft.Extensions.Primitives;
+using Microsoft.Net.Http.Headers;
 
 namespace Microsoft.AspNetCore.Server.HttpSys
 {
-    internal class HeaderCollection : IDictionary<string, StringValues>
+    internal class HeaderCollection : IHeaderDictionary
     {
+        private long? _contentLength;
+        private StringValues _contentLengthText;
+
         public HeaderCollection()
             : this(new Dictionary<string, StringValues>(4, StringComparer.OrdinalIgnoreCase))
         {
@@ -75,6 +80,52 @@ public ICollection<StringValues> Values
             get { return Store.Values; }
         }
 
+        public long? ContentLength
+        {
+            get
+            {
+                long value;
+                var rawValue = this[HttpKnownHeaderNames.ContentLength];
+
+                if (_contentLengthText.Equals(rawValue))
+                {
+                    return _contentLength;
+                }
+
+                if (rawValue.Count == 1 &&
+                    !string.IsNullOrWhiteSpace(rawValue[0]) &&
+                    HeaderUtilities.TryParseInt64(new StringSegment(rawValue[0]).Trim(), out value))
+                {
+                    _contentLengthText = rawValue;
+                    _contentLength = value;
+                    return value;
+                }
+
+                return null;
+            }
+            set
+            {
+                ThrowIfReadOnly();
+
+                if (value.HasValue)
+                {
+                    if (value.Value < 0)
+                    {
+                        throw new ArgumentOutOfRangeException("value", value.Value, "Cannot be negative.");
+                    }
+                    _contentLengthText = HeaderUtilities.FormatInt64(value.Value);
+                    this[HttpKnownHeaderNames.ContentLength] = _contentLengthText;
+                    _contentLength = value;
+                }
+                else
+                {
+                    Remove(HttpKnownHeaderNames.ContentLength);
+                    _contentLengthText = StringValues.Empty;
+                    _contentLength = null;
+                }
+            }
+        }
+
         public void Add(KeyValuePair<string, StringValues> item)
         {
             ThrowIfReadOnly();

src/Microsoft.AspNetCore.Server.HttpSys/RequestProcessing/HeaderCollection.cs

@@ -147,48 +147,8 @@ internal long ExpectedBodyLength
         // Header accessors
         public long? ContentLength
         {
-            get
-            {
-                string contentLengthString = Headers[HttpKnownHeaderNames.ContentLength];
-                long contentLength;
-                if (!string.IsNullOrWhiteSpace(contentLengthString))
-                {
-                    contentLengthString = contentLengthString.Trim();
-                    if (string.Equals(Constants.Zero, contentLengthString, StringComparison.Ordinal))
-                    {
-                        return 0;
-                    }
-                    else if (long.TryParse(contentLengthString, NumberStyles.None, CultureInfo.InvariantCulture.NumberFormat, out contentLength))
-                    {
-                        return contentLength;
-                    }
-                }
-                return null;
-            }
-            set
-            {
-                CheckResponseStarted();
-                if (!value.HasValue)
-                {
-                    Headers.Remove(HttpKnownHeaderNames.ContentLength);
-                }
-                else
-                {
-                    if (value.Value < 0)
-                    {
-                        throw new ArgumentOutOfRangeException("value", value.Value, "Cannot be negative.");
-                    }
-
-                    if (value.Value == 0)
-                    {
-                        Headers[HttpKnownHeaderNames.ContentLength] = Constants.Zero;
-                    }
-                    else
-                    {
-                        Headers[HttpKnownHeaderNames.ContentLength] = value.Value.ToString(CultureInfo.InvariantCulture);
-                    }
-                }
-            }
+            get { return Headers.ContentLength; }
+            set { Headers.ContentLength = value; }
         }
 
         /// <summary>

src/Microsoft.AspNetCore.Server.HttpSys/RequestProcessing/Response.cs

@@ -83,7 +83,7 @@ public async Task Request_FieldsCanBeSet_Set()
                     Assert.Equal("TEST", requestInfo.Method);
                     requestInfo.Body = new MemoryStream();
                     Assert.IsType<MemoryStream>(requestInfo.Body);
-                    var customHeaders = new HeaderDictionary(new HeaderCollection());
+                    var customHeaders = new HeaderCollection();
                     requestInfo.Headers = customHeaders;
                     Assert.Same(customHeaders, requestInfo.Headers);
                     requestInfo.Scheme = "abcd";