How to create a Script Mapper in Keycloak?

Question

I need to create a Protocol Mapper of type Script Mapper in Keycloak. The script should get a user attribute, check its size, and put it on the token. I found no documentati

Answer 1

The magic of Script Mappers can be understood by looking at the keycloak sources here: Source

The script can return something by using the exports variable like this

exports = "Claim Value"

The different types:

• user: Source JavaDoc
• realm: Source JavaDoc
• token: Source JavaDoc
• userSession: Source JavaDoc
• keycloakSession: Source JavaDoc

Here is an example script:

// you can set standard fields in token
token.setAcr("test value");

// you can set claims in the token
token.getOtherClaims().put("claimName", "claim value");

// work with variables and return multivalued token value
var ArrayList = Java.type("java.util.ArrayList");
var roles = new ArrayList();
var client = keycloakSession.getContext().getClient();
var forEach = Array.prototype.forEach;
forEach.call(user.getClientRoleMappings(client).toArray(), function(roleModel) {
  roles.add(roleModel.getName());
});

exports = roles;

Hope it helps!