No String anymore. :)

ampel-firmware/web_server.cpp

@@ -262,7 +262,9 @@ namespace web_server {
     }
     if (FS_LIB.exists(csv_writer::filename)) {
       fs::File csv_file = FS_LIB.open(csv_writer::filename, "r");
-      http.sendHeader("Content-Length", String(csv_file.size()));
+      char csv_size[10];
+      snprintf(csv_size, sizeof(csv_size), "%d", csv_file.size());
+      http.sendHeader("Content-Length", csv_size);
       http.streamFile(csv_file, F("text/csv"));
       csv_file.close();
     } else {
@@ -274,9 +276,9 @@ namespace web_server {
     if (!shouldBeAllowed()) {
       return http.requestAuthentication(DIGEST_AUTH);
     }
-    Serial.print("Removing CSV file...");
+    Serial.print(F("Removing CSV file..."));
     FS_LIB.remove(csv_writer::filename);
-    Serial.println(" Done!");
+    Serial.println(F(" Done!"));
     http.sendHeader("Location", "/");
     http.send(303);
   }