AuthClientSigningExtension extension

Extension providing smart signing capabilities for AuthClient.

This extension adds a universal sign method that automatically selects the appropriate signing strategy based on the authentication context:

  1. ImpersonatedAuthClient: Uses IAM signBlob with the target principal
  2. Service account credentials: Uses local RSA-SHA256 signing
  3. Other auth clients (ADC on GCE/Cloud Run): Uses IAM signBlob with the default service account from metadata server

Example usage:

// Works with service account credentials
final client = await clientViaServiceAccount(credentials, scopes);
final signature = await client.sign(utf8.encode('data to sign'));

// Works with ADC on GCE/Cloud Run
final client = await clientViaApplicationDefaultCredentials(scopes: scopes);
final signature = await client.sign(utf8.encode('data to sign'));

// Works with impersonated credentials
final client = await clientViaServiceAccountImpersonation(
  sourceClient: sourceClient,
  targetServiceAccount: 'target@project.iam.gserviceaccount.com',
  targetScopes: scopes,
);
final signature = await client.sign(utf8.encode('data to sign'));
on

Methods

sign(List<int> data, {String? endpoint}) → Future<String>

Available on AuthClient, provided by the AuthClientSigningExtension extension

Signs some bytes using the credentials from this auth client.