概述
前后端分离之后，因为HTTP本身是无状态的，Session就没法用了。项目采用jwt的方案后，请求的主要流程如下：用户登录成功之后，服务端会创建一个jwt的token（jwt的这个token中记录了当前的操作账号），并将这个token返回给前端，前端每次请求服务端的数据时，都会将令牌放入Header或者Parameter中，服务端接收到请求后，会先被拦截器拦截，token检验的拦截器会获取请求中的token，然后会检验token的有效性，拦截器都检验成功后，请求会成功到达实际的业务流程中，执行业务逻辑返回给前端数据。在这个过程中，主要涉及到Shiro的拦截器链，Jwt的token管理，多Realm配置等。
Shiro的Filter链
Shiro的认证和授权都离不开Filter，因此需要对Shiro的Filter的运行流程很清楚，才能自定义Filter来满足企业的实际需要。另外Shiro的Filter虽然原理都和Servlet的Filter相似，甚至都最终继承相同的接口，但是实际还是有些差别。Shiro中的Filter主要是在ShiroFilter内，对指定匹配的URL进行拦截处理，它有自己的Filter链；而Servlet的Filter和ShiroFilter是同一个级别的，即先走Shiro自己的Filter体系，然后才会委托给Servlet容器的FilterChain进行Servlet容器级别的Filter链执行
分析Shiro的默认Filter
在Shiro和Spring Boot整合过程中，需要配置ShiroFilterFactoryBean，该类是ShiroFilter的工厂类，并继承了FactoryBean接口。可以从该接口的方法来分析。该接口getObject获取一个实例，按照逻辑，发现调用createFilterChainManager，并创建默认的Filter(按照命名猜测Map<String, Filter> defaultFilters = manager.getFilters())。
public class ShiroFilterFactoryBean implements FactoryBean, BeanPostProcessor {
private Map<String, Filter> filters;
private Map<String, String> filterChainDefinitionMap;
/**
*
* 该工厂类生产的产品类
*/
public Object getObject() throws Exception {
if (instance == null) {
instance = createInstance();
}
return instance;
}
protected FilterChainManager createFilterChainManager() {
//创建默认Filter
DefaultFilterChainManager manager = new DefaultFilterChainManager();
Map<String, Filter> defaultFilters = manager.getFilters();
for (Filter filter : defaultFilters.values()) {
applyGlobalPropertiesIfNecessary(filter);
}
Map<String, Filter> filters = getFilters();
if (!CollectionUtils.isEmpty(filters)) {
for (Map.Entry<String, Filter> entry : filters.entrySet()) {
String name = entry.getKey();
Filter filter = entry.getValue();
applyGlobalPropertiesIfNecessary(filter);
if (filter instanceof Nameable) {
((Nameable) filter).setName(name);
}
manager.addFilter(name, filter, false);
}
}
Map<String, String> chains = getFilterChainDefinitionMap();
if (!CollectionUtils.isEmpty(chains)) {
for (Map.Entry<String, String> entry : chains.entrySet()) {
String url = entry.getKey();
String chainDefinition = entry.getValue();
manager.createChain(url, chainDefinition);
}
}
return manager;
}
protected AbstractShiroFilter createInstance() throws Exception {
log.debug("Creating Shiro Filter instance.");
SecurityManager securityManager = getSecurityManager();
if (securityManager == null) {
String msg = "SecurityManager property must be set.";
throw new BeanInitializationException(msg);
}
if (!(securityManager instanceof WebSecurityManager)) {
String msg = "The security manager does not implement the WebSecurityManager interface.";
throw new BeanInitializationException(msg);
}
//创建FilterChainManager
FilterChainManager manager = createFilterChainManager();
PathMatchingFilterChainResolver chainResolver = new PathMatchingFilterChainResolver();
chainResolver.setFilterChainManager(manager);
return new SpringShiroFilter((WebSecurityManager) securityManager, chainResolver);
}
...
}
在DefaultFilterChainManager中addDefaultFilters来添加默认的Filter，DefaultFilter为一系列默认Filter的枚举类。
public class DefaultFilterChainManager implements FilterChainManager {
public Map<String, Filter> getFilters() {
return filters;
}
protected void addFilter(String name, Filter filter, boolean init, boolean overwrite) {
Filter existing = getFilter(name);
if (existing == null || overwrite) {
if (filter instanceof Nameable) {
((Nameable) filter).setName(name);
}
if (init) {
initFilter(filter);
}
this.filters.put(name, filter);
}
}
/**
*
* 创建默认的Filter
*/
protected void addDefaultFilters(boolean init) {
for (DefaultFilter defaultFilter : DefaultFilter.values()) {
addFilter(defaultFilter.name(), defaultFilter.newInstance(), init, false);
}
}
...
}
从这个枚举类中可以看到之前添加的共有11个默认Filter，它们的名字分别是anon,authc,authcBaisc等。
public enum DefaultFilter {
anon(AnonymousFilter.class),
authc(FormAuthenticationFilter.class),
authcBasic(BasicHttpAuthenticationFilter.class),
logout(LogoutFilter.class),
noSessionCreation(NoSessionCreationFilter.class),
perms(PermissionsAuthorizationFilter.class),
port(PortFilter.class),
rest(HttpMethodPermissionFilter.class),
roles(RolesAuthorizationFilter.class),
ssl(SslFilter.class),
user(UserFilter.class);
private final Class<? extends Filter> filterClass;
private DefaultFilter(Class<? extends Filter> filterClass) {
this.filterClass = filterClass;
}
public Filter newInstance() {
return (Filter) ClassUtils.newInstance(this.filterClass);
}
public Class<? extends Filter> getFilterClass() {
return this.filterClass;
}
...
}Filter的继承体系分析
NameableFilter给Filter起个名字，如果没有设置，默认名字就是FilterName。
OncePerRequestFilter用于防止多次执行Filter；也就是说一次请求只会走一次拦截器链；另外提供 enabled 属性，表示是否开启该拦截器实例，默认 enabled=true 表示开启，如果不想让某个拦截器工作，可以设置为 false 即可。
AdviceFilter提供了AOP风格的支持。preHandler：在拦截器链执行之前执行，如果返回true则继续拦截器链；否则中断后续的拦截器链的执行直接返回；可以进行预处理（如身份验证、授权等行为）。postHandle：在拦截器链执行完成后执行，后置处理（如记录执行时间之类的）。afterCompletion：类似于AOP中的后置最终增强；即不管有没有异常都会执行，可以进行清理资源（如接触 Subject 与线程的绑定之类的）。
PathMatchingFilter内置了pathMatcher的实例，方便对请求路径匹配功能及拦截器参数解析的功能，如下所示，对匹配的路径执行
isFilterChainContinued的逻辑，如果都没配到，则直接交给拦截器链。
protected boolean preHandle(ServletRequest request, ServletResponse response) throws Exception {
if (this.appliedPaths == null || this.appliedPaths.isEmpty()) {
if (log.isTraceEnabled()) {
log.trace("appliedPaths property is null or empty. This Filter will passthrough immediately.");
}
return true;
}
for (String path : this.appliedPaths.keySet()) {
//对匹配路径进行处理
if (pathsMatch(path, request)) {
log.trace("Current requestURI matches pattern '{}'. Determining filter chain execution...", path);
Object config = this.appliedPaths.get(path);
return isFilterChainContinued(request, response, path, config);
}
}
return true;
}- AccessControlFilter提供了访问控制的基础功能，isAccessAllowed访问通过，则交给拦截器链，不通过则执行
onAccessDenied来确定交给拦截器还是自己处理
public boolean onPreHandle(ServletRequest request, ServletResponse response, Object mappedValue) throws Exception {
return isAccessAllowed(request, response, mappedValue) || onAccessDenied(request, response, mappedValue);
}
- AuthenticationFilter认证Filter的基类，一般在isAccessAllowed中执行认证逻辑，另外该Filter提供登录成功后跳转的功能
protected boolean isAccessAllowed(ServletRequest request, ServletResponse response, Object mappedValue) {
Subject subject = getSubject(request, response);
return subject.isAuthenticated();
}
protected void issueSuccessRedirect(ServletRequest request, ServletResponse response) throws Exception {
WebUtils.redirectToSavedRequest(request, response, getSuccessUrl());
}- AuthenticatingFilter是AuthenticationFilter的子类，提供了
executeLogin通用逻辑，通常由子类来实现protected abstract AuthenticationToken createToken(ServletRequest request, ServletResponse response)该方法，然后执行subject.login(token)
public abstract class AuthenticatingFilter extends AuthenticationFilter {
public static final String PERMISSIVE = "permissive";
protected boolean executeLogin(ServletRequest request, ServletResponse response) throws Exception {
AuthenticationToken token = createToken(request, response);
if (token == null) {
String msg = "createToken method implementation returned null. A valid non-null AuthenticationToken " +
"must be created in order to execute a login attempt.";
throw new IllegalStateException(msg);
}
try {
Subject subject = getSubject(request, response);
subject.login(token);
return onLoginSuccess(token, subject, request, response);
} catch (AuthenticationException e) {
return onLoginFailure(token, e, request, response);
}
}
protected abstract AuthenticationToken createToken(ServletRequest request, ServletResponse response) throws Exception;
protected AuthenticationToken createToken(String username, String password,
ServletRequest request, ServletResponse response) {
boolean rememberMe = isRememberMe(request);
String host = getHost(request);
return createToken(username, password, rememberMe, host);
}
protected AuthenticationToken createToken(String username, String password,
boolean rememberMe, String host) {
return new UsernamePasswordToken(username, password, rememberMe, host);
}
protected boolean onLoginSuccess(AuthenticationToken token, Subject subject,
ServletRequest request, ServletResponse response) throws Exception {
return true;
}
protected boolean onLoginFailure(AuthenticationToken token, AuthenticationException e,
ServletRequest request, ServletResponse response) {
return false;
}
@Override
protected boolean isAccessAllowed(ServletRequest request, ServletResponse response, Object mappedValue) {
return super.isAccessAllowed(request, response, mappedValue) ||
(!isLoginRequest(request, response) && isPermissive(mappedValue));
}
...
}在Shiro中添加自定义的Filter
从上面源码分析，知道了Shiro会提供11个默认的Filter，也是按照拦截器模式交由FilterChainManager来管理Filter，并最终返回SpringShiroFilter。所以添加自定义的Filter，主要有三步。
- 实现自己的Filter
如下实现了自己的JwtFilter，主要逻辑可以参考FormAuthenticationFilter。JwtFilter主要是对前端的Api进行校验，检验失败，则抛出异常信息，不给拦截器链处理。
@Slf4j
public class JwtFilter extends AuthenticatingFilter {
private static final String TOKEN_NAME = "token";
/**
* 创建令牌
*/
@Override
protected AuthenticationToken createToken(ServletRequest servletRequest, ServletResponse servletResponse) throws Exception {
final String token = getToken((HttpServletRequest) servletRequest);
if(StringUtils.isEmpty(token)) {
return null;
}
return new JwtToken(token);
}
/**
* 获取令牌
* @param httpServletRequest
* @return
*/
private String getToken(HttpServletRequest httpServletRequest) {
String token = httpServletRequest.getHeader(TOKEN_NAME);
if(StringUtils.isEmpty(token)) {
token = httpServletRequest.getParameter(TOKEN_NAME);
};
if(StringUtils.isEmpty(token)) {
Cookie[] cookies = httpServletRequest.getCookies();
if(ArrayUtils.isNotEmpty(cookies)) {
for(Cookie cookie :cookies) {
if(TOKEN_NAME.equals(cookie.getName())) {
token = cookie.getValue();
break;
}
}
}
};
return token;
}
/**
* 未通过处理
* @param servletRequest
* @param servletResponse
* @return
* @throws Exception
*/
@Override
protected boolean onAccessDenied(ServletRequest servletRequest, ServletResponse servletResponse) throws Exception {
return executeLogin(servletRequest, servletResponse);
}
/**
* 登录失败执行方法
* @param token
* @param e
* @param request
* @param response
* @return
*/
protected boolean onLoginFailure(AuthenticationToken token, AuthenticationException e, ServletRequest request,
ServletResponse response) {
response.setContentType("text/html;charset=UTF-8");
try(OutputStream outputStream = response.getOutputStream()){
outputStream.write(e.getMessage().getBytes(SystemConsts.CHARSET));
outputStream.flush();
} catch (IOException e1) {
e1.printStackTrace();
}
return false;
}
...
}- 将Filter添加到Shiro中
将自定义的Filter添加到Shiro，并要指定的匹配路径。
public ShiroFilterFactoryBean getShiroFilterFactoryBean(@Autowired org.apache.shiro.mgt.SecurityManager securityManager, @Autowired JwtFilter jwtFilter) {
ShiroFilterFactoryBean shiroFilterFactoryBean = new ShiroFilterFactoryBean();
Map<String, Filter> filterMap = new LinkedHashMap<>();
filterMap.put("jwt", jwtFilter);
shiroFilterFactoryBean.setFilters(filterMap);
Map<String, String> filterChainDefinitionMap = new LinkedHashMap<>();
filterChainDefinitionMap.put("/**", "jwt");
shiroFilterFactoryBean.setFilterChainDefinitionMap(filterChainDefinitionMap);
...
return shiroFilterFactoryBean;
}注意：SpringBoot自动帮我们注册了我们的Filter(Filter是注册到整个Filter链，而不是Shiro的Filter链)，但是在Shiro中，我们需要自己实现注册，但是又需要Filter实例存在于Spring容器中，以便能使用其他众多服务(自动注入其他组件……)。所以需要取消Spring Boot的自动注入Filter。可以采用如下方式：
@Bean
public FilterRegistrationBean registration(@Qualifier("devCryptoFilter") DevCryptoFilter filter）{
FilterRegistrationBean registration = new FilterRegistrationBean(filter);
registration.setEnabled(false);
return registration;
}Jwt整合
使用Jwt需要我们提供对token的创建，校验和获取token中信息的方法。网上有很多，可以借鉴，而且token中也可以存一些其他数据。
public class JwtUtil {
/**
* 检验token
* @return boolean
*/
public static boolean verify(String token, String username) {
...
}
/**
* 获得token中的属性
* @return token中包含的属性
*/
public static String getValue(String token, String key) {
...
}
/**
* 生成token签名EXPIRE_TIME 分钟后过期
*
* @param username
* 用户名
* @return 加密的token
*/
public static String createJWT(String userId) {
...
}
}多Realm配置
用户密码认证和Jwt的认证需要不同的两个Realm，多Realm需要处理不同的Realm，获取到指定Realm的AuthenticationToken的数据模型。
- 实现ModularRealmAuthenticator的方法
public class MultiRealmAuthenticator extends ModularRealmAuthenticator {
@Override
protected AuthenticationInfo doAuthenticate(AuthenticationToken authenticationToken)
throws AuthenticationException {
assertRealmsConfigured();
List<Realm> realms = this.getRealms()
.stream()
.filter(realm -> {
return realm.supports(authenticationToken);
})
.collect(Collectors.toList());
return realms.size() == 1 ? this.doSingleRealmAuthentication(realms.get(0), authenticationToken) :
this.doMultiRealmAuthentication(realms, authenticationToken);
}
}- AuthenticatingRealm中实现
getAuthenticationTokenClass方法
public Class getAuthenticationTokenClass() {
return JwtToken.class;
}- 在SecurityManager中配置
@Bean(name = "securityManager")
public org.apache.shiro.mgt.SecurityManager defaultWebSecurityManager(@Autowired UserRealm userRealm, @Autowired TokenRealm tokenValidateRealm) {
securityManager.setAuthenticator(multiRealmAuthenticator());
securityManager.setRealms(Arrays.asList(userRealm, tokenValidateRealm));
...
return securityManager;
}整合Swagger
添加Swagger依赖
<dependency>
<groupId>io.springfox</groupId>
<artifactId>springfox-swagger2</artifactId>
<version>2.9.2</version>
</dependency>
<dependency>
<groupId>io.springfox</groupId>
<artifactId>springfox-swagger-ui</artifactId>
<version>2.9.2</version>
</dependency>添加Swagger的配置
@Configuration
public class Swagger2Config {
@Bean
public Docket createRestApi() {
return new Docket(DocumentationType.SWAGGER_2)
.apiInfo(apiInfo())
.select()
.apis(RequestHandlerSelectors.basePackage("XXX"))
.paths(PathSelectors.any())
.build();
}
private ApiInfo apiInfo() {
return new ApiInfoBuilder()
.title("XXX")
.description("经供参考")
.version("1.0")
.build();
}
}总结
在整个过程中，遇到的坑就是在Spring boot中Filter的自动注入，中间考虑有不使用注入的方式解决，即直接使用new JwtFilter()的方式，虽然也能解决问题，但是不是很完美，最终还是在网上找到解决方案。对Shiro的Filter链的执行过程加强了理解，能够使用自定的Filter解决实际问题。还有一个后续的问题，退出登录时的Jwt的token处理，它本身不能像Session一样，退出就清除，理论上只要没过期，就一直存在。可以考虑使用缓存，退出时清除即可，然后在校验时，先从缓存获取进行判断。
