refactor: code cleanup, stricter config validation (#155)

lib/response_writer.go

@@ -0,0 +1,27 @@
+package lib
+
+import "net/http"
+
+var _ http.ResponseWriter = responseWriterNoBody{}
+
+// responseWriterNoBody is a wrapper used to suppress the body of the response
+// to a request. Mainly used for HEAD requests.
+type responseWriterNoBody struct {
+	http.ResponseWriter
+}
+
+// newResponseWriterNoBody creates a new responseWriterNoBody.
+func newResponseWriterNoBody(w http.ResponseWriter) *responseWriterNoBody {
+	return &responseWriterNoBody{w}
+}
+
+// Write suppress the body.
+func (w responseWriterNoBody) Write(data []byte) (int, error) {
+	return 0, nil
+}
+
+// WriteHeader writes the header to the http.ResponseWriter.
+func (w responseWriterNoBody) WriteHeader(statusCode int) {
+	w.Header().Del("Content-Length")
+	w.ResponseWriter.WriteHeader(statusCode)
+}