auth0_rule_onboard.js

function (user, context, callback) {
  
  // Only support users with a verified email address
  if (!user.email || !user.email_verified) {
    return callback(null, user, context);
  }
  
  // Only onboard the user to the ledger once
  if (user.app_metadata && user.app_metadata.daml_ledger_api) {
  	return callback(null, user, context);
  }
  
  // Construct the the DAML party identifier from the email
  // We could also use a random UUID string here
  var partyIdentifier = user.email.replace(/\W/gi, "-");
  
  // TODO: Allocated the party on the ledger
  // This step is not necessary for the sandbox, as it has an
  // open world of parties.
  
  // Save the new app metadata
  user.app_metadata = user.app_metadata || {};
  user.app_metadata.daml_ledger_api = {
    partyIdentifier
  };
  auth0.users.updateAppMetadata(user.user_id, user.app_metadata)
    .then(function(){
        callback(null, user, context);
    })
    .catch(function(err){
        callback(err);
    });
}