Resolving Content Security Policy Script Loading Errors in an Electron-React Firebase App

Below is one common solution when Firebase’s SDK attempts to load extra resources dynamically and your strict content security policy blocks them.

What's Happening

Firebase’s Realtime Database SDK sometimes dynamically injects scripts (for example, to load vendor resources from Google’s domains). In your Electron app the current CSP restricts scripts to only inline and self-loaded scripts. When Firebase tries to load a script from Google’s domains, the browser blocks it because it isn’t explicitly allowed.

The Fix

You need to update your Content Security Policy to allow the domains Firebase uses. For example, include Google’s static domains in your CSP. One way to adjust your meta tag is:

HTMLCopied
<meta http-equiv="Content-Security-Policy" content="
  default-src 'self';
  script-src 'self' 'unsafe-inline' 'unsafe-eval' https://www.gstatic.com https://www.googleapis.com;
">

This change lets your app load additional scripts from those approved sources while still maintaining a tighter security posture.

Alternative Approach

Consider bundling Firebase via npm rather than relying on dynamic script loading. By importing Firebase modules using your bundler (Webpack, etc.), you avoid runtime external script injection. For example:

JAVASCRIPTCopied
import { initializeApp } from 'firebase/app';
import { getDatabase, ref } from "firebase/database";

const firebaseConfig = {
  apiKey: "<my_key>",
  authDomain: "app-data-no.firebaseapp.com",
  databaseURL: "https://app-data-no.firebaseio.com",
  projectId: "app-data-no",
  storageBucket: "app-data-no.firebasestorage.app",
  messagingSenderId: "<123>",
  appId: "1:<123>"
};

const app = initializeApp(firebaseConfig);
const database = getDatabase(app);
const historyRef = ref(database, 'history');

By doing so, the Firebase code is bundled into your app and no extra remote script is loaded at runtime, sidestepping the CSP issue entirely.

Summary

• Option 1: Relax your CSP to allow Firebase’s external resources (e.g. add https://www.gstatic.com and https://www.googleapis.com to script-src).
• Option 2: Bundle Firebase via your module bundler (Webpack) so that external dynamic loading isn’t required.

Either approach can solve the issue. Adjust the solution based on your security requirements and deployment context.