fixes, meaningful error messages and new features

src/go-proxy/file_reader.go

@@ -0,0 +1,23 @@
+package main
+
+import "os"
+
+type Reader interface {
+	Read() ([]byte, error)
+}
+
+type FileReader struct {
+	Path string
+}
+
+func (r *FileReader) Read() ([]byte, error) {
+	return os.ReadFile(r.Path)
+}
+
+type ByteReader struct {
+	Data []byte
+}
+
+func (r *ByteReader) Read() ([]byte, error) {
+	return r.Data, nil
+}