fancyWriters should also implement io.ReaderFrom

For sendfile(2) support. I should really DRY up the implementations here...

graceful/middleware.go

@@ -2,6 +2,7 @@ package graceful
 
 import (
 	"bufio"
+	"io"
 	"net"
 	"net/http"
 )
@@ -36,10 +37,11 @@ func Middleware(h http.Handler) http.Handler {
 		_, cn := w.(http.CloseNotifier)
 		_, fl := w.(http.Flusher)
 		_, hj := w.(http.Hijacker)
+		_, rf := w.(io.ReaderFrom)
 
 		bw := basicWriter{ResponseWriter: w}
 
-		if cn && fl && hj {
+		if cn && fl && hj && rf {
 			h.ServeHTTP(&fancyWriter{bw}, r)
 		} else {
 			h.ServeHTTP(&bw, r)
@@ -104,3 +106,15 @@ func (f *fancyWriter) Hijack() (c net.Conn, b *bufio.ReadWriter, e error) {
 
 	return
 }
+func (f *fancyWriter) ReadFrom(r io.Reader) (int64, error) {
+	rf := f.basicWriter.ResponseWriter.(io.ReaderFrom)
+	if !f.basicWriter.headerWritten {
+		f.basicWriter.maybeClose()
+	}
+	return rf.ReadFrom(r)
+}
+
+var _ http.CloseNotifier = &fancyWriter{}
+var _ http.Flusher = &fancyWriter{}
+var _ http.Hijacker = &fancyWriter{}
+var _ io.ReaderFrom = &fancyWriter{}

web/middleware/logger.go

@@ -78,16 +78,3 @@ func printEnd(reqId string, w writerProxy, dt time.Duration) {
 
 	log.Print(buf.String())
 }
-
-func wrapWriter(w http.ResponseWriter) writerProxy {
-	_, cn := w.(http.CloseNotifier)
-	_, fl := w.(http.Flusher)
-	_, hj := w.(http.Hijacker)
-
-	bw := basicWriter{ResponseWriter: w}
-	if cn && fl && hj {
-		return &fancyWriter{bw}
-	} else {
-		return &bw
-	}
-}

web/middleware/writer_proxy.go

@@ -2,10 +2,25 @@ package middleware
 
 import (
 	"bufio"
+	"io"
 	"net"
 	"net/http"
 )
 
+func wrapWriter(w http.ResponseWriter) writerProxy {
+	_, cn := w.(http.CloseNotifier)
+	_, fl := w.(http.Flusher)
+	_, hj := w.(http.Hijacker)
+	_, rf := w.(io.ReaderFrom)
+
+	bw := basicWriter{ResponseWriter: w}
+	if cn && fl && hj && rf {
+		return &fancyWriter{bw}
+	} else {
+		return &bw
+	}
+}
+
 type writerProxy interface {
 	http.ResponseWriter
 	maybeWriteHeader()
@@ -55,7 +70,13 @@ func (f *fancyWriter) Hijack() (net.Conn, *bufio.ReadWriter, error) {
 	hj := f.basicWriter.ResponseWriter.(http.Hijacker)
 	return hj.Hijack()
 }
+func (f *fancyWriter) ReadFrom(r io.Reader) (int64, error) {
+	rf := f.basicWriter.ResponseWriter.(io.ReaderFrom)
+	f.basicWriter.maybeWriteHeader()
+	return rf.ReadFrom(r)
+}
 
 var _ http.CloseNotifier = &fancyWriter{}
 var _ http.Flusher = &fancyWriter{}
 var _ http.Hijacker = &fancyWriter{}
+var _ io.ReaderFrom = &fancyWriter{}