## 获取token 上一篇博客中我们尝试使用了password模式和client模式，有一个比较关键的endpoint：/oauth/token。从这个入口开始分析，spring security oauth2内部是如何生成token的。 首先开启debug信息： ~~~ logging: level: org.springframework: DEBUG ~~~ 可以完整的看到内部的运转流程。 client模式稍微简单一些，使用client模式获取token `http://localhost:8080/oauth/token? client_id=client_1&client_secret=123456&scope=select&grant_type=client_credentials` 由于debug信息太多了，我简单按照顺序列了一下关键的几个类： ~~~ ClientCredentialsTokenEndpointFilter DaoAuthenticationProvider TokenEndpoint TokenGranter ~~~ ## ClientCredentialsTokenEndpointFilter和DaoAuthenticationProvider 截取关键的代码，可以分析出大概的流程 在请求到达/oauth/token之前经过了ClientCredentialsTokenEndpointFilter这个过滤器，关键方法如下 ~~~ public Authentication attemptAuthentication(HttpServletRequest request, HttpServletResponse response) throws AuthenticationException, IOException, ServletException { ... String clientId = request.getParameter("client_id"); String clientSecret = request.getParameter("client_secret"); ... clientId = clientId.trim(); UsernamePasswordAuthenticationToken authRequest = new UsernamePasswordAuthenticationToken(clientId, clientSecret); return this.getAuthenticationManager().authenticate(authRequest); } ~~~ 用来从请求中获取client_id,client_secret，组装成一个UsernamePasswordAuthenticationToken作为身份标识，使用容器中的顶级身份管理器AuthenticationManager去进行身份认证（AuthenticationManager的实现类一般是ProviderManager。而ProviderManager内部维护了一个List,真正的身份认证是由一系列AuthenticationProvider去完成。而AuthenticationProvider的常用实现类则是DaoAuthenticationProvider，DaoAuthenticationProvider内部又聚合了一个UserDetailsService接口，UserDetailsService才是获取用户详细信息的最终接口，而我们上一篇文章中在内存中配置用户，就是使用了UserDetailsService的一个实现类InMemoryUserDetailsManager）。UML类图可以大概理解下这些类的关系，省略了授权部分。  可能机智的读者会发现一个问题，我前面一片文章已经提到了client模式是不存在“用户”的概念的，那么这里的身份认证是在认证什么呢？debug可以发现UserDetailsService的实现被适配成了ClientDetailsUserDetailsService，这个设计是将client客户端的信息（client_id,client_secret）适配成用户的信息(username,password)，这样我们的认证流程就不需要修改了。 经过ClientCredentialsTokenEndpointFilter之后，身份信息已经得到了AuthenticationManager的验证。接着便到达了 TokenEndpoint。 ## TokenEndpoint 前面的两个ClientCredentialsTokenEndpointFilter和DaoAuthenticationProvider可以理解为一些前置校验，和身份封装，而这个类一看名字就知道和我们的token是密切相关的。 ~~~ @FrameworkEndpoint public class TokenEndpoint extends AbstractEndpoint { @RequestMapping(value = "/oauth/token", method=RequestMethod.POST) public ResponseEntity<OAuth2AccessToken> postAccessToken(Principal principal, @RequestParam Map<String, String> parameters) throws HttpRequestMethodNotSupportedException { ... String clientId = getClientId(principal); ClientDetails authenticatedClient = getClientDetailsService().loadClientByClientId(clientId); ... TokenRequest tokenRequest = getOAuth2RequestFactory().createTokenRequest(parameters, authenticatedClient); ... OAuth2AccessToken token = getTokenGranter().grant(tokenRequest.getGrantType(), tokenRequest); ... return getResponse(token); } private TokenGranter tokenGranter; } ~~~ 省略了一些校验代码之后，真正的/oauth/token端点暴露在了我们眼前，其中方法参数中的Principal经过之前的过滤器，已经被填充了相关的信息，而方法的内部则是依赖了一个TokenGranter 来颁发token。其中OAuth2AccessToken的实现类DefaultOAuth2AccessToken就是最终在控制台得到的token序列化之前的原始类: ~~~ public class DefaultOAuth2AccessToken implements Serializable, OAuth2AccessToken { private static final long serialVersionUID = 914967629530462926L; private String value; private Date expiration; private String tokenType = BEARER_TYPE.toLowerCase(); private OAuth2RefreshToken refreshToken; private Set<String> scope; private Map<String, Object> additionalInformation = Collections.emptyMap(); //getter,setter } @org.codehaus.jackson.map.annotate.JsonSerialize(using = OAuth2AccessTokenJackson1Serializer.class) @org.codehaus.jackson.map.annotate.JsonDeserialize(using = OAuth2AccessTokenJackson1Deserializer.class) @com.fasterxml.jackson.databind.annotation.JsonSerialize(using = OAuth2AccessTokenJackson2Serializer.class) @com.fasterxml.jackson.databind.annotation.JsonDeserialize(using = OAuth2AccessTokenJackson2Deserializer.class) public interface OAuth2AccessToken { public static String BEARER_TYPE = "Bearer"; public static String OAUTH2_TYPE = "OAuth2"; /** * The access token issued by the authorization server. This value is REQUIRED. */ public static String ACCESS_TOKEN = "access_token"; /** * The type of the token issued as described in <a * href="http://tools.ietf.org/html/draft-ietf-oauth-v2-22#section-7.1">Section 7.1</a>. Value is case insensitive. * This value is REQUIRED. */ public static String TOKEN_TYPE = "token_type"; /** * The lifetime in seconds of the access token. For example, the value "3600" denotes that the access token will * expire in one hour from the time the response was generated. This value is OPTIONAL. */ public static String EXPIRES_IN = "expires_in"; /** * The refresh token which can be used to obtain new access tokens using the same authorization grant as described * in <a href="http://tools.ietf.org/html/draft-ietf-oauth-v2-22#section-6">Section 6</a>. This value is OPTIONAL. */ public static String REFRESH_TOKEN = "refresh_token"; /** * The scope of the access token as described by <a * href="http://tools.ietf.org/html/draft-ietf-oauth-v2-22#section-3.3">Section 3.3</a> */ public static String SCOPE = "scope"; ... } ~~~ 一个典型的样例token响应,如下所示，就是上述类序列化后的结果： ~~~ { "access_token":"950a7cc9-5a8a-42c9-a693-40e817b1a4b0", "token_type":"bearer", "refresh_token":"773a0fcd-6023-45f8-8848-e141296cb3cb", "expires_in":27036, "scope":"select" } ~~~ ## TokenGranter 先从UML类图对TokenGranter接口的设计有一个宏观的认识  TokenGranter的设计思路是使用CompositeTokenGranter管理一个List列表，每一种grantType对应一个具体的真正授权者，在debug过程中可以发现CompositeTokenGranter 内部就是在循环调用五种TokenGranter实现类的grant方法，而granter内部则是通过grantType来区分是否是各自的授权类型。 ~~~ public class CompositeTokenGranter implements TokenGranter { private final List<TokenGranter> tokenGranters; public CompositeTokenGranter(List<TokenGranter> tokenGranters) { this.tokenGranters = new ArrayList<TokenGranter>(tokenGranters); } public OAuth2AccessToken grant(String grantType, TokenRequest tokenRequest) { for (TokenGranter granter : tokenGranters) { OAuth2AccessToken grant = granter.grant(grantType, tokenRequest); if (grant!=null) { return grant; } } return null; } } ~~~ 五种类型分别是： * ResourceOwnerPasswordTokenGranter ==> password密码模式 * AuthorizationCodeTokenGranter ==> authorization_code授权码模式 * ClientCredentialsTokenGranter ==> client_credentials客户端模式 * ImplicitTokenGranter ==> implicit简化模式 * RefreshTokenGranter ==>refresh_token 刷新token专用 以客户端模式为例，思考如何产生token的，则需要继续研究5种授权者的抽象类：AbstractTokenGranter ~~~ public abstract class AbstractTokenGranter implements TokenGranter { protected final Log logger = LogFactory.getLog(getClass()); //与token相关的service，重点 private final AuthorizationServerTokenServices tokenServices; //与clientDetails相关的service，重点 private final ClientDetailsService clientDetailsService; //创建oauth2Request的工厂，重点 private final OAuth2RequestFactory requestFactory; private final String grantType; ... public OAuth2AccessToken grant(String grantType, TokenRequest tokenRequest) { ... String clientId = tokenRequest.getClientId(); ClientDetails client = clientDetailsService.loadClientByClientId(clientId); validateGrantType(grantType, client); logger.debug("Getting access token for: " + clientId); return getAccessToken(client, tokenRequest); } protected OAuth2AccessToken getAccessToken(ClientDetails client, TokenRequest tokenRequest) { return tokenServices.createAccessToken(getOAuth2Authentication(client, tokenRequest)); } protected OAuth2Authentication getOAuth2Authentication(ClientDetails client, TokenRequest tokenRequest) { OAuth2Request storedOAuth2Request = requestFactory.createOAuth2Request(client, tokenRequest); return new OAuth2Authentication(storedOAuth2Request, null); } ... } ~~~ 回过头去看TokenEndpoint中，正是调用了这里的三个重要的类变量的相关方法。由于篇幅限制，不能延展太多，不然没完没了，所以重点分析下AuthorizationServerTokenServices是何方神圣。 ## AuthorizationServerTokenServices ~~~ public interface AuthorizationServerTokenServices { //创建token OAuth2AccessToken createAccessToken(OAuth2Authentication authentication) throws AuthenticationException; //刷新token OAuth2AccessToken refreshAccessToken(String refreshToken, TokenRequest tokenRequest) throws AuthenticationException; //获取token OAuth2AccessToken getAccessToken(OAuth2Authentication authentication); } ~~~ 在默认的实现类DefaultTokenServices中，可以看到token是如何产生的，并且了解了框架对token进行哪些信息的关联。 ~~~ @Transactional public OAuth2AccessToken createAccessToken(OAuth2Authentication authentication) throws AuthenticationException { OAuth2AccessToken existingAccessToken = tokenStore.getAccessToken(authentication); OAuth2RefreshToken refreshToken = null; if (existingAccessToken != null) { if (existingAccessToken.isExpired()) { if (existingAccessToken.getRefreshToken() != null) { refreshToken = existingAccessToken.getRefreshToken(); // The token store could remove the refresh token when the // access token is removed, but we want to // be sure... tokenStore.removeRefreshToken(refreshToken); } tokenStore.removeAccessToken(existingAccessToken); } else { // Re-store the access token in case the authentication has changed tokenStore.storeAccessToken(existingAccessToken, authentication); return existingAccessToken; } } // Only create a new refresh token if there wasn't an existing one // associated with an expired access token. // Clients might be holding existing refresh tokens, so we re-use it in // the case that the old access token // expired. if (refreshToken == null) { refreshToken = createRefreshToken(authentication); } // But the refresh token itself might need to be re-issued if it has // expired. else if (refreshToken instanceof ExpiringOAuth2RefreshToken) { ExpiringOAuth2RefreshToken expiring = (ExpiringOAuth2RefreshToken) refreshToken; if (System.currentTimeMillis() > expiring.getExpiration().getTime()) { refreshToken = createRefreshToken(authentication); } } OAuth2AccessToken accessToken = createAccessToken(authentication, refreshToken); tokenStore.storeAccessToken(accessToken, authentication); // In case it was modified refreshToken = accessToken.getRefreshToken(); if (refreshToken != null) { tokenStore.storeRefreshToken(refreshToken, authentication); } return accessToken; } ~~~ 简单总结一下AuthorizationServerTokenServices的作用，他提供了创建token，刷新token，获取token的实现。在创建token时，他会调用tokenStore对产生的token和相关信息存储到对应的实现类中，可以是Redis，数据库，内存，jwt。 ## 总结 本篇总结了使用客户端模式获取Token时，spring security oauth2内部的运作流程，其他模式有一定的不同，但抽象功能是固定的，只是具体的实现类会被响应地替换。阅读spring的源码，会发现它的设计中出现了非常多的抽象接口，这对我们理清楚内部工作流程产生了不小的困扰，我的方式是可以借助UML类图，先从宏观理清楚作者的设计思路，这会让我们的分析事半功倍。 下一篇文章重点分析用户携带token访问受限资源时，spring security oauth2内部的工作流程。