retrievePassphrase method

@override Future<String?> retrievePassphrase(AuthenticatedLicense license, AuthenticationReason reason, bool allowUserInteraction, { Object? sender, })

Retrieves the passphrase used to decrypt the given license.

If allowUserInteraction is true, the reading app can prompt the user to enter the passphrase. Otherwise, use a background retrieval method (e.g. web service) or return null.

The returned passphrase can be clear or already hashed.

You can implement an asynchronous pop-up with callbacks using suspendCoroutine:

suspendCoroutine<String?> { cont ->
    cancelButton.setOnClickListener {
        cont.resume(null)
    }

    okButton.setOnClickListener {
        cont.resume(passwordEditText.text.toString())
    }

    // show pop-up...
}

@param license Information to show to the user about the license being opened. @param reason Reason why the passphrase is requested. It should be used to prompt the user. @param allowUserInteraction Indicates whether the user can be prompted for their passphrase. @param sender Free object that can be used by reading apps to give some UX context when presenting dialogs.

Implementation

@override
Future<String?> retrievePassphrase(AuthenticatedLicense license,
    AuthenticationReason reason, bool allowUserInteraction,
    {Object? sender}) async {
  if (reason != AuthenticationReason.passphraseNotFound) {
    return fallback?.retrievePassphrase(
        license, reason, allowUserInteraction = allowUserInteraction,
        sender: sender);
  }
  return passphrase;
}