working commit

app/handler/copywctx.go

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2026 Oleg Borodin <onborodin@gmail.com>
+ */
+package handler
+
+import (
+	"context"
+	"errors"
+	"io"
+)
+
+func CopyWithContext(ctx context.Context, writer io.Writer, reader io.Reader) (int64, error) {
+	var err error
+	var size int64
+	var halt bool
+	buffer := make([]byte, 1024*4)
+	for {
+		select {
+		case <-ctx.Done():
+			err = errors.New("Break copy by context")
+			break
+		default:
+		}
+		rsize, err := reader.Read(buffer)
+		if err == io.EOF {
+			err = nil
+			halt = true
+		}
+		if err != nil {
+			return size, err
+		}
+		wsize, err := writer.Write(buffer[0:rsize])
+		size += int64(wsize)
+		if err != nil {
+			return size, err
+		}
+		if halt {
+			break
+		}
+	}
+	return size, err
+}