private function setAccountKeyAndContinue(PhabricatorExternalAccount $account, $next_uri)
{
if ($account->getUserPHID()) {
throw new Exception(pht('Account is already registered or linked.'));
}
// Regenerate the registration secret key, set it on the external account,
// set a cookie on the user's machine, and redirect them to registration.
// See PhabricatorAuthRegisterController for discussion of the registration
// key.
$registration_key = Filesystem::readRandomCharacters(32);
$account->setProperty('registrationKey', PhabricatorHash::digest($registration_key));
$unguarded = AphrontWriteGuard::beginScopedUnguardedWrites();
$account->save();
unset($unguarded);
$this->getRequest()->setTemporaryCookie(PhabricatorCookies::COOKIE_REGISTRATION, $registration_key);
return id(new AphrontRedirectResponse())->setURI($next_uri);
}
