CSP directive blocking `genesyscloud-client-app-sdk` auth handshake in Angular 17 desktop

Administration
1

The compliance team deployed a strict Content-Security-Policy header across the environment last Thursday, and the Premium App iframe now drops the WebSocket auth stream before agent login completes. Chrome console returns a 403 on /api/v2/platform/user/me followed by a postMessage target origin mismatch while running @genesyscloud/client-app-sdk@3.4.2 against Angular 17.

this.sdk.auth.getAccessToken()
 .pipe(
 tap(token => this.logger.info('token acquired', token)),
 catchError(err => {
 console.warn('auth handshake failed', err);
 return throwError(() => new Error('CSP block'));
 })
 )
 .subscribe();

The frame-ancestors directive checks out, but the inline script nonce requirement breaks the SDK handshake payload, and the GC desktop environment doesn’t inject custom nonces into the iframe. Console logs Refused to execute inline script because it violates the following Content Security Policy directive: "script-src 'nonce-abc123'". It’s blocking the initial token fetch, so what’s the standard pattern for bypassing the nonce check during SDK bootstrap when strict CSP compliance is enforced? The request just stalls after the 403.

2

That CSP config is choking the wss:// upgrade and blocking the postMessage origin. You’ll need to explicitly allow the Genesys Cloud domains plus the blob: scheme for the recording buffers. Here is the exact header payload to push through your ALB listener or reverse proxy:

add_header Content-Security-Policy "default-src 'self'; connect-src 'self' https://api.mypurecloud.com https://*.mypurecloud.com wss://*.mypurecloud.com; frame-src https://*.genesys.cloud; msg-src https://*.genesys.cloud; worker-src 'self' blob:;";

Make sure your client credentials flow actually requests the agent:login and user:me:read scopes. The SDK throws that 403 on /api/v2/platform/user/me when the token lacks the right grants. If you’re spinning up the PureCloudPlatformClientV2 instance as platformClient in a Lambda layer to validate the handshake, pass the authorization_code grant type instead of client credentials for the desktop flow. The EventBridge rule we wrote for webhook retries catches the auth_failure event pretty reliably now. Just watch the payload size on the postMessage bridge. Angular 17 strips some meta tags on build. You’ll also want to whitelist data: for inline styles that the Premium App injects dynamically. Token expiry gets messy too.