Eagerly disable buffering

Author: JunTaoLuo

src/Microsoft.AspNetCore.ResponseCaching/Internal/ResponseCacheStream.cs

@@ -11,10 +11,12 @@ namespace Microsoft.AspNetCore.ResponseCaching.Internal
     internal class ResponseCacheStream : Stream
     {
         private readonly Stream _innerStream;
+        private readonly long _maxBufferSize;
 
-        public ResponseCacheStream(Stream innerStream)
+        public ResponseCacheStream(Stream innerStream, long maxBufferSize)
         {
             _innerStream = innerStream;
+            _maxBufferSize = maxBufferSize;
         }
 
         public MemoryStream BufferedStream { get; } = new MemoryStream();
@@ -77,7 +79,14 @@ public override void Write(byte[] buffer, int offset, int count)
 
             if (BufferingEnabled)
             {
-                BufferedStream.Write(buffer, offset, count);
+                if (BufferedStream.Length + count > _maxBufferSize)
+                {
+                    DisableBuffering();
+                }
+                else
+                {
+                    BufferedStream.Write(buffer, offset, count);
+                }
             }
         }
 
@@ -95,7 +104,14 @@ public override async Task WriteAsync(byte[] buffer, int offset, int count, Canc
 
             if (BufferingEnabled)
             {
-                await BufferedStream.WriteAsync(buffer, offset, count, cancellationToken);
+                if (BufferedStream.Length + count > _maxBufferSize)
+                {
+                    DisableBuffering();
+                }
+                else
+                {
+                    await BufferedStream.WriteAsync(buffer, offset, count, cancellationToken);
+                }
             }
         }
 
@@ -113,7 +129,14 @@ public override void WriteByte(byte value)
 
             if (BufferingEnabled)
             {
-                BufferedStream.WriteByte(value);
+                if (BufferedStream.Length + 1 > _maxBufferSize)
+                {
+                    DisableBuffering();
+                }
+                else
+                {
+                    BufferedStream.WriteByte(value);
+                }
             }
         }
 

src/Microsoft.AspNetCore.ResponseCaching/ResponseCachingContext.cs

@@ -594,9 +594,7 @@ internal void FinalizeCachingHeaders()
 
         internal void FinalizeCachingBody()
         {
-            if (CacheResponse &&
-                ResponseCacheStream.BufferingEnabled &&
-                !(_options.MaximumCachedBodySize < ResponseCacheStream.BufferedStream.Length))
+            if (CacheResponse && ResponseCacheStream.BufferingEnabled)
             {
                 _cachedResponse.Body = ResponseCacheStream.BufferedStream.ToArray();
 
@@ -621,7 +619,7 @@ internal void ShimResponseStream()
 
             // Shim response stream
             OriginalResponseStream = _httpContext.Response.Body;
-            ResponseCacheStream = new ResponseCacheStream(OriginalResponseStream);
+            ResponseCacheStream = new ResponseCacheStream(OriginalResponseStream, _options.MaximumCachedBodySize);
             _httpContext.Response.Body = ResponseCacheStream;
 
             // Shim IHttpSendFileFeature

src/Microsoft.AspNetCore.ResponseCaching/ResponseCachingOptions.cs

@@ -11,7 +11,7 @@ public class ResponseCachingOptions
         /// <summary>
         /// The largest cacheable size for the response body in bytes.
         /// </summary>
-        public int? MaximumCachedBodySize { get; set; }
+        public long MaximumCachedBodySize { get; set; } = 1024 * 1024;
 
         /// <summary>
         /// For testing purposes only.