[release/7.0] Fix RequestBody logging when zero byte read is used (#47811)

* Fix RequestBody logging when zero byte read is used

* consistency

---------

Co-authored-by: Brennan <[email protected]>

Author: github-actions[bot]

src/Middleware/HttpLogging/src/RequestBufferingStream.cs

@@ -27,6 +27,12 @@ public override async ValueTask<int> ReadAsync(Memory<byte> destination, Cancell
     {
         var res = await _innerStream.ReadAsync(destination, cancellationToken);
 
+        // Zero-byte reads (where the passed in buffer has 0 length) can occur when using PipeReader, we don't want to accidentally complete the RequestBody logging in this case
+        if (destination.IsEmpty)
+        {
+            return res;
+        }
+
         WriteToBuffer(destination.Slice(0, res).Span);
 
         return res;
@@ -36,6 +42,12 @@ public override async Task<int> ReadAsync(byte[] buffer, int offset, int count,
     {
         var res = await _innerStream.ReadAsync(buffer.AsMemory(offset, count), cancellationToken);
 
+        // Zero-byte reads (where the passed in buffer has 0 length) can occur when using PipeReader, we don't want to accidentally complete the RequestBody logging in this case
+        if (count == 0)
+        {
+            return res;
+        }
+
         WriteToBuffer(buffer.AsSpan(offset, res));
 
         return res;
@@ -45,6 +57,12 @@ public override int Read(byte[] buffer, int offset, int count)
     {
         var res = _innerStream.Read(buffer, offset, count);
 
+        // Zero-byte reads (where the passed in buffer has 0 length) can occur when using PipeReader, we don't want to accidentally complete the RequestBody logging in this case
+        if (count == 0)
+        {
+            return res;
+        }
+
         WriteToBuffer(buffer.AsSpan(offset, res));
 
         return res;

src/Middleware/HttpLogging/test/HttpLoggingMiddlewareTests.cs

@@ -434,6 +434,33 @@ public async Task PartialReadBodyStillLogs()
         Assert.Contains(TestSink.Writes, w => w.Message.Equals("RequestBody: " + expected));
     }
 
+    [Fact]
+    public async Task ZeroByteReadStillLogsRequestBody()
+    {
+        var input = string.Concat(new string('a', 60000), new string('b', 3000));
+        var options = CreateOptionsAccessor();
+        options.CurrentValue.LoggingFields = HttpLoggingFields.RequestBody;
+
+        var middleware = new HttpLoggingMiddleware(
+            async c =>
+            {
+                var arr = new byte[4096];
+                _ = await c.Request.Body.ReadAsync(new byte[0]);
+                var res = await c.Request.Body.ReadAsync(arr);
+            },
+            options,
+            LoggerFactory.CreateLogger<HttpLoggingMiddleware>());
+
+        var httpContext = new DefaultHttpContext();
+        httpContext.Request.ContentType = "text/plain";
+        httpContext.Request.Body = new MemoryStream(Encoding.UTF8.GetBytes(input));
+
+        await middleware.Invoke(httpContext);
+        var expected = input.Substring(0, 4096);
+
+        Assert.Contains(TestSink.Writes, w => w.Message.Equals("RequestBody: " + expected));
+    }
+
     [Theory]
     [InlineData("text/plain")]
     [InlineData("text/html")]