encode: write status immediately when status code is informational (#6164)

modules/caddyhttp/encode/encode.go

@@ -20,11 +20,9 @@
 package encode
 
 import (
-	"bufio"
 	"fmt"
 	"io"
 	"math"
-	"net"
 	"net/http"
 	"sort"
 	"strconv"
@@ -221,6 +219,12 @@ type responseWriter struct {
 // to actually write the header.
 func (rw *responseWriter) WriteHeader(status int) {
 	rw.statusCode = status
+
+	// write status immediately when status code is informational
+	// see: https://caddy.community/t/disappear-103-early-hints-response-with-encode-enable-caddy-v2-7-6/23081/5
+	if 100 <= status && status <= 199 {
+		rw.ResponseWriter.WriteHeader(status)
+	}
 }
 
 // Match determines, if encoding should be done based on the ResponseMatcher.
@@ -242,19 +246,6 @@ func (rw *responseWriter) Flush() {
 	http.NewResponseController(rw.ResponseWriter).Flush()
 }
 
-// Hijack implements http.Hijacker. It will flush status code if set. We don't track actual hijacked
-// status assuming http middlewares will track its status.
-func (rw *responseWriter) Hijack() (net.Conn, *bufio.ReadWriter, error) {
-	if !rw.wroteHeader {
-		if rw.statusCode != 0 {
-			rw.ResponseWriter.WriteHeader(rw.statusCode)
-		}
-		rw.wroteHeader = true
-	}
-	//nolint:bodyclose
-	return http.NewResponseController(rw.ResponseWriter).Hijack()
-}
-
 // Write writes to the response. If the response qualifies,
 // it is encoded using the encoder, which is initialized
 // if not done so already.