don’t panic if a request handler replaces the request.Body

fixes #405

h2quic/server.go

@@ -162,7 +162,8 @@ func (s *Server) handleRequest(session streamCreator, headerStream utils.Stream,
 		_, _ = dataStream.Read([]byte{0}) // read the eof
 	}
 
-	req.Body = newRequestBody(dataStream)
+	reqBody := newRequestBody(dataStream)
+	req.Body = reqBody
 
 	responseWriter := newResponseWriter(headerStream, headerStreamMutex, dataStream, protocol.StreamID(h2headersFrame.StreamID))
 
@@ -191,7 +192,7 @@ func (s *Server) handleRequest(session streamCreator, headerStream utils.Stream,
 			responseWriter.WriteHeader(200)
 		}
 		if responseWriter.dataStream != nil {
-			if !streamEnded && !req.Body.(*requestBody).requestRead {
+			if !streamEnded && !reqBody.requestRead {
 				responseWriter.dataStream.Reset(nil)
 			}
 			responseWriter.dataStream.Close()

h2quic/server_test.go

@@ -2,6 +2,7 @@ package h2quic
 
 import (
 	"bytes"
+	"io"
 	"net"
 	"net/http"
 	"os"
@@ -152,6 +153,23 @@ var _ = Describe("H2 server", func() {
 			Expect(handlerCalled).To(BeTrue())
 		})
 
+		It("resets the dataStream when the body of POST request is not read, and the request handler replaces the request.Body", func() {
+			var handlerCalled bool
+			s.Handler = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				r.Body = struct {
+					io.Reader
+					io.Closer
+				}{}
+				handlerCalled = true
+			})
+			headerStream.dataToRead.Write([]byte{0x0, 0x0, 0x20, 0x1, 0x24, 0x0, 0x0, 0x0, 0x5, 0x0, 0x0, 0x0, 0x0, 0xff, 0x41, 0x8c, 0xf1, 0xe3, 0xc2, 0xe5, 0xf2, 0x3a, 0x6b, 0xa0, 0xab, 0x90, 0xf4, 0xff, 0x83, 0x84, 0x87, 0x5c, 0x1, 0x37, 0x7a, 0x85, 0xed, 0x69, 0x88, 0xb4, 0xc7})
+			err := s.handleRequest(session, headerStream, &sync.Mutex{}, hpackDecoder, h2framer)
+			Expect(err).NotTo(HaveOccurred())
+			Eventually(func() bool { return dataStream.reset }).Should(BeTrue())
+			Consistently(func() bool { return dataStream.remoteClosed }).Should(BeFalse())
+			Expect(handlerCalled).To(BeTrue())
+		})
+
 		It("closes the dataStream if the body of POST request was read", func() {
 			var handlerCalled bool
 			s.Handler = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {