/*
 * Copyright 2018-2020 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.springframework.cloud.common.security.support;

import java.util.Map;

/**
 * The default implementation of the {@link PrincipalExtractor} that extracts the username
 * of the principal.
 *
 * @author Gunnar Hillert
 *
 */
public class DefaultPrincipalExtractor implements PrincipalExtractor {

	private static final String[] PRINCIPAL_KEYS = new String[] { "user_name", "user", "username",
			"userid", "user_id", "login", "id", "name", "cid", "client_id" };

	@Override
	public Object extractPrincipal(Map<String, Object> map) {
		for (String key : PRINCIPAL_KEYS) {
			if (map.containsKey(key)) {
				return map.get(key);
			}
		}
		return null;
	}
}
