From 4b86381b2be4d57400a61114a88f23a9b6a6843e Mon Sep 17 00:00:00 2001
From: catalingavan <catalingavan@gmail.com>
Date: Sun, 26 Dec 2021 11:39:56 +0100
Subject: [PATCH] fixes #54

---
 src/KissLog.AspNetCore/KissLogMiddleware.cs |  5 ++++-
 src/KissLog/MirrorStreamDecorator.cs        | 17 ++++++++++++++---
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/src/KissLog.AspNetCore/KissLogMiddleware.cs b/src/KissLog.AspNetCore/KissLogMiddleware.cs
index a6009cf..5ca5c8e 100644
--- a/src/KissLog.AspNetCore/KissLogMiddleware.cs
+++ b/src/KissLog.AspNetCore/KissLogMiddleware.cs
@@ -44,7 +44,10 @@ public async Task Invoke(HttpContext context)
 
             ExceptionDispatchInfo ex = null;
             
-            context.Response.Body = new MirrorStreamDecorator(context.Response.Body);
+            if(context.Response.Body != null && context.Response.Body is MirrorStreamDecorator == false)
+            {
+                context.Response.Body = new MirrorStreamDecorator(context.Response.Body);
+            }
 
             try
             {
diff --git a/src/KissLog/MirrorStreamDecorator.cs b/src/KissLog/MirrorStreamDecorator.cs
index 670a2f8..9f0c716 100644
--- a/src/KissLog/MirrorStreamDecorator.cs
+++ b/src/KissLog/MirrorStreamDecorator.cs
@@ -48,13 +48,17 @@ public override Task<int> ReadAsync(byte[] buffer, int offset, int count, Cancel
         public override void Write(byte[] buffer, int offset, int count)
         {
             _decorated.Write(buffer, offset, count);
-            _mirrorStream.Write(buffer, offset, count);
+
+            if(_mirrorStream?.CanWrite == true)
+                _mirrorStream.Write(buffer, offset, count);
         }
 
         public override async Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
         {
             await _decorated.WriteAsync(buffer, offset, count, cancellationToken);
-            _mirrorStream.Write(buffer, offset, count);
+
+            if (_mirrorStream?.CanWrite == true)
+                _mirrorStream.Write(buffer, offset, count);
         }
 
         public override long Seek(long offset, SeekOrigin origin)
@@ -65,7 +69,9 @@ public override long Seek(long offset, SeekOrigin origin)
         public override void SetLength(long value)
         {
             _decorated.SetLength(value);
-            _mirrorStream.SetLength(value);
+
+            if (_mirrorStream?.CanWrite == true)
+                _mirrorStream.SetLength(value);
         }
 
         public override void Flush()
@@ -73,6 +79,11 @@ public override void Flush()
             _decorated.Flush();
         }
 
+        public override Task FlushAsync(CancellationToken cancellationToken)
+        {
+            return _decorated.FlushAsync(cancellationToken);
+        }
+
         public override void Close()
         {
             _decorated.Close();