Initial commit: DSH Web Manager

internal/api/response_buffer.go

@@ -0,0 +1,39 @@
+package api
+
+import (
+	"bytes"
+	"net/http"
+)
+
+// Only use for bounded JSON responses, never file or runtime streams. Register
+// flush before lock-release defers so a slow client cannot hold storage locks.
+func deferJSONResponse(w http.ResponseWriter) (http.ResponseWriter, func()) {
+	b := &jsonResponseBuffer{ResponseWriter: w}
+	return b, func() {
+		if b.status != 0 {
+			w.WriteHeader(b.status)
+		}
+		if b.body.Len() > 0 {
+			_, _ = w.Write(b.body.Bytes())
+		}
+	}
+}
+
+type jsonResponseBuffer struct {
+	http.ResponseWriter
+	body   bytes.Buffer
+	status int
+}
+
+func (w *jsonResponseBuffer) WriteHeader(status int) {
+	if w.status == 0 {
+		w.status = status
+	}
+}
+func (w *jsonResponseBuffer) Write(p []byte) (int, error) {
+	if w.status == 0 {
+		w.status = http.StatusOK
+	}
+	return w.body.Write(p)
+}
+func (w *jsonResponseBuffer) Unwrap() http.ResponseWriter { return w.ResponseWriter }