IHttpRequestBodyDetectionFeature for HTTP/3 GET requests

src/Http/Http.Features/src/IHttpRequestBodyDetectionFeature.cs

@@ -20,6 +20,9 @@ public interface IHttpRequestBodyDetectionFeature
     /// <item><description>
     /// It's an HTTP/2 request that did not set the END_STREAM flag on the initial headers frame.
     /// </description></item>
+    /// <item><description>
+    /// It's an HTTP/3 request that did not set the END_STREAM flag on the initial headers frame.
+    /// </description></item>
     /// </list>
     /// The final request body length may still be zero for the chunked or HTTP/2 scenarios.
     /// <para>
@@ -35,6 +38,9 @@ public interface IHttpRequestBodyDetectionFeature
     /// <item><description>
     /// It's an HTTP/2 request that set END_STREAM on the initial headers frame.
     /// </description></item>
+    /// <item><description>
+    /// It's an HTTP/3 request that set END_STREAM on the initial headers frame.
+    /// </description></item>
     /// </list>
     /// </para>
     /// When false, the request body should never return data.

src/Servers/Kestrel/Core/src/Internal/Http3/Http3Stream.cs

@@ -54,6 +54,7 @@ internal abstract partial class Http3Stream : HttpProtocol, IHttp3Stream, IHttpS
     private bool _isMethodConnect;
     private bool _isWebTransportSessionAccepted;
     private Http3MessageBody? _messageBody;
+    private bool _requestBodyStarted;
 
     private readonly ManualResetValueTaskSource<object?> _appCompletedTaskSource = new();
     private readonly Lock _completionLock = new();
@@ -65,6 +66,17 @@ internal abstract partial class Http3Stream : HttpProtocol, IHttp3Stream, IHttpS
     private bool IsAbortedRead => (_completionState & StreamCompletionFlags.AbortedRead) == StreamCompletionFlags.AbortedRead;
     public bool IsCompleted => (_completionState & StreamCompletionFlags.Completed) == StreamCompletionFlags.Completed;
 
+    public bool ReceivedEmptyRequestBody
+    {
+        get
+        {
+            lock (_completionLock)
+            {
+                return EndStreamReceived && !_requestBodyStarted;
+            }
+        }
+    }
+
     public Pipe RequestBodyPipe { get; private set; } = default!;
     public long? InputRemaining { get; internal set; }
     public QPackDecoder QPackDecoder { get; private set; } = default!;
@@ -559,7 +571,7 @@ private void CompleteStream(bool errored)
 
             TryClose();
         }
-
+        RequestBodyPipe.Reader.Complete();
         _http3Output.Complete();
 
         // Stream will be pooled after app completed.
@@ -928,7 +940,7 @@ private Task ProcessDataFrameAsync(in ReadOnlySequence<byte> payload)
             {
                 return Task.CompletedTask;
             }
-
+            _requestBodyStarted = true;
             foreach (var segment in payload)
             {
                 RequestBodyPipe.Writer.Write(segment.Span);
@@ -966,6 +978,11 @@ protected override string CreateRequestId()
 
     protected override MessageBody CreateMessageBody()
     {
+        if (ReceivedEmptyRequestBody)
+        {
+            return MessageBody.ZeroContentLengthClose;
+        }
+
         if (_messageBody != null)
         {
             _messageBody.Reset();

src/Servers/Kestrel/test/InMemory.FunctionalTests/Http3/Http3StreamTests.cs

@@ -3291,6 +3291,32 @@ public async Task Control_FrameParsingSingleByteAtATimeWorks()
         await outboundcontrolStream.ReceiveEndAsync();
     }
 
+    [Theory]
+    [InlineData(true)]
+    [InlineData(false)]
+    public async Task CanHaveBody_ReturnsFalseWithoutRequestBody(bool endstream)
+    {
+        var headers = new[]
+        {
+            new KeyValuePair<string, string>(InternalHeaderNames.Method, "GET"),
+            new KeyValuePair<string, string>(InternalHeaderNames.Path, "/"),
+            new KeyValuePair<string, string>(InternalHeaderNames.Scheme, "http"),
+            new KeyValuePair<string, string>(InternalHeaderNames.Authority, "localhost:80"),
+        };
+
+        var requestStream = await Http3Api.InitializeConnectionAndStreamsAsync(context =>
+        {
+            Assert.Equal(!endstream, context.Features.Get<IHttpRequestBodyDetectionFeature>().CanHaveBody);
+            context.Response.StatusCode = 200;
+            return Task.CompletedTask;
+        }, headers, endStream: endstream);
+
+        var responseHeaders = await requestStream.ExpectHeadersAsync();
+        Assert.Equal("200", responseHeaders[InternalHeaderNames.Status]);
+
+        await requestStream.ExpectReceiveEndOfStream();
+    }
+
     private async Task WriteOneByteAtATime(PipeReader reader, PipeWriter writer)
     {
         var res = await reader.ReadAsync();