taverna-server-webapp/src/main/java/org/taverna/server/master/identity/AuthorityDerivedIDMapper.java

/*
 */
package org.taverna.server.master.identity;
/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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
 *
 *      http://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.
 */

import static org.taverna.server.master.defaults.Default.AUTHORITY_PREFIX;

import org.springframework.security.core.Authentication;
import org.springframework.security.core.GrantedAuthority;
import org.springframework.security.core.context.SecurityContextHolder;
import org.taverna.server.master.interfaces.LocalIdentityMapper;
import org.taverna.server.master.utils.UsernamePrincipal;

/**
 * Extracts the local user id from the set of Spring Security authorities
 * granted to the current user. This is done by scanning the set of authorities
 * to see if any of them start with the substring listed in the <tt>prefix</tt>
 * property; the username is the rest of the authority string in that case.
 * 
 * @author Donal Fellows
 */
public class AuthorityDerivedIDMapper implements LocalIdentityMapper {
	private String prefix = AUTHORITY_PREFIX;

	public String getPrefix() {
		return prefix;
	}

	public void setPrefix(String prefix) {
		this.prefix = prefix;
	}

	@Override
	public String getUsernameForPrincipal(UsernamePrincipal user) {
		Authentication auth = SecurityContextHolder.getContext()
				.getAuthentication();
		if (auth == null || !auth.isAuthenticated())
			return null;
		for (GrantedAuthority authority : auth.getAuthorities()) {
			String token = authority.getAuthority();
			if (token == null)
				continue;
			if (token.startsWith(prefix))
				return token.substring(prefix.length());
		}
		return null;
	}
}