vscode-webview-expert

Content Security Policy protects WebViews from XSS attacks by restricting script and style sources. Generate a CSP that allows resources from your extension's media directory, then apply it via the WebView's `cspSource` and `localResourceRoots` configuration to safely load scripts and styles.

Extension-WebView communication uses message passing protocols. Define a message contract, send data from the extension using `webview.postMessage()`, and listen on the WebView side with `window.addEventListener('message')`. This ensures reliable, secure data exchange between processes.

WebView state management requires storing data in the extension's storage backend and restoring it on panel creation. Use `context.globalState` or `context.workspaceState` to persist state, then pass it to the WebView on initialization so content survives hide/show cycles and restarts.

Enforce Content Security Policy, validate all messages between extension and WebView, restrict resource loading to `localResourceRoots`, avoid inline scripts, and use `nonce` attributes for dynamic script injection to prevent injection attacks and unauthorized access.

Yes. WebViews support custom editor implementations through the `CustomEditorProvider` API, enabling rich UI for document types. Combine WebView panels with state persistence and secure messaging to build performant custom editors with full VS Code integration.