Java tutorial
/* * Copyright 2006-2016 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.security.oauth2.provider.token; import org.springframework.security.oauth2.common.util.OAuth2Utils; import org.springframework.security.oauth2.provider.OAuth2Authentication; import org.springframework.security.oauth2.provider.OAuth2Request; import java.io.UnsupportedEncodingException; import java.math.BigInteger; import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; import java.util.LinkedHashMap; import java.util.Map; import java.util.TreeSet; /** * Basic key generator taking into account the client id, scope, resource ids and username (principal name) if they * exist. * * @author Dave Syer * */ public class DefaultAuthenticationKeyGenerator implements AuthenticationKeyGenerator { private static final String CLIENT_ID = "client_id"; private static final String SCOPE = "scope"; private static final String USERNAME = "username"; public String extractKey(OAuth2Authentication authentication) { Map<String, String> values = new LinkedHashMap<String, String>(); OAuth2Request authorizationRequest = authentication.getOAuth2Request(); if (!authentication.isClientOnly()) { values.put(USERNAME, authentication.getName()); } values.put(CLIENT_ID, authorizationRequest.getClientId()); if (authorizationRequest.getScope() != null) { values.put(SCOPE, OAuth2Utils.formatParameterList(new TreeSet<String>(authorizationRequest.getScope()))); } return generateKey(values); } protected String generateKey(Map<String, String> values) { MessageDigest digest; try { digest = MessageDigest.getInstance("MD5"); byte[] bytes = digest.digest(values.toString().getBytes("UTF-8")); return String.format("%032x", new BigInteger(1, bytes)); } catch (NoSuchAlgorithmException nsae) { throw new IllegalStateException("MD5 algorithm not available. Fatal (should be in the JDK).", nsae); } catch (UnsupportedEncodingException uee) { throw new IllegalStateException("UTF-8 encoding not available. Fatal (should be in the JDK).", uee); } } }