摘要：
接下来，我们将基于Shiro的注释权限控制方案为后台界面提供权限保护。权限注释Shiro总共有5个权限注释，它们实现了不同的权限控制策略。添加以下内容以启用Shiro的权限注释。Shiro通过AOP拦截由权限注释的类或方法，然后匹配权限注释值和用户权限列表进行验证。
技术背景
当前，我们基于导航菜单的显示和操作按钮的禁用状态，实现了页面可见性和操作可用性的权限验证，或者叫访问控制。但这仅限于页面的显示和操作，我们的后台接口还是没有进行权限的验证，只要知道了后台的接口信息，就可以直接通过swagger或自行发送ajax请求成功调用后台接口，这是非常危险的。接下来，我们就基于Shiro的注解式权限控制方案，来给我们的后台接口提供权限保护。
权限注解
Shiro总共有5个权限注解，实现了不同的权限控制策略。
RequiresPermissions
当前Subject需要拥有某些特定的权限时，才能执行被该注解标注的方法。如果当前Subject不具有这样的权限，则方法不会被执行。
这是基于资源权限方式的权限控制主要方案，也是我们项目中进行权限控制使用的注解方案。
RequiresRoles
当前Subject必须拥有所有指定的角色时，才能访问被该注解标注的方法。如果当天Subject不同时拥有所有指定角色，则方法不会执行还会抛出AuthorizationException异常。
RequiresUser
当前Subject必须是应用的用户，才能访问或调用被该注解标注的类，实例，方法。
RequiresAuthentication
使用该注解标注的类，实例，方法在访问或调用时，当前Subject必须在当前session中已经过认证。
RequiresGuest
使用该注解标注的类，实例，方法在访问或调用时，当前Subject可以是“gust”身份，不需要经过认证或者在原先的session中存在记录。
注解优先级
Shiro的认证注解处理具有内定处理顺序，如有多个注解，会按照下面优先级逐个检查，只有所有检查通过才允许访问：
- RequiresRoles
- RequiresPermissions
- RequiresAuthentication
- RequiresUser
- RequiresGuest
代码实现
添加配置
打开kitty-admin工程，找到shiro配置类。添加如下内容，主要作用是开启Shiro的权限注解。
Shiro通过AOP方式拦截被权限注解的类或方法，然后匹配权限注解值和用户权限列表进行验证。
ShiroConfig.java
/**
* Shiro生命周期处理器
*/
@Bean
public LifecycleBeanPostProcessor lifecycleBeanPostProcessor() {
return new LifecycleBeanPostProcessor();
}
/**
* 开启Shiro的注解(如@RequiresRoles,@RequiresPermissions),需借助SpringAOP扫描使用Shiro注解的类,并在必要时进行安全逻辑验证
* 配置以下两个bean(DefaultAdvisorAutoProxyCreator(可选)和AuthorizationAttributeSourceAdvisor)即可实现此功能
*/
@Bean
@DependsOn({"lifecycleBeanPostProcessor"})
public DefaultAdvisorAutoProxyCreator advisorAutoProxyCreator() {
DefaultAdvisorAutoProxyCreator advisorAutoProxyCreator = new DefaultAdvisorAutoProxyCreator();
advisorAutoProxyCreator.setProxyTargetClass(true);
return advisorAutoProxyCreator;
}
@Bean
public AuthorizationAttributeSourceAdvisor authorizationAttributeSourceAdvisor() {
AuthorizationAttributeSourceAdvisor authorizationAttributeSourceAdvisor = new AuthorizationAttributeSourceAdvisor();
authorizationAttributeSourceAdvisor.setSecurityManager(securityManager());
return authorizationAttributeSourceAdvisor;
}添加注解
以菜单管理接口为例，添加 @RequiresPermissions("权限标识") 标识即可。
这个权限标识就是我们的菜单表中对应的权限标识字段（perms）对应的值。
SysMenuController.java
package com.louis.kitty.admin.controller;
import java.util.List;
import org.apache.shiro.authz.annotation.RequiresPermissions;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import com.louis.kitty.admin.model.SysMenu;
import com.louis.kitty.admin.sevice.SysMenuService;
import com.louis.kitty.core.http.HttpResult;
/**
* 菜单控制器
* @author Louis
* @date Oct 29, 2018
*/
@RestController
@RequestMapping("menu")
public class SysMenuController {
@Autowired
private SysMenuService sysMenuService;
@RequiresPermissions({"sys:menu:add", "sys:menu:edit"})
@PostMapping(value="/save")
public HttpResult save(@RequestBody SysMenu record) {
return HttpResult.ok(sysMenuService.save(record));
}
@RequiresPermissions("sys:menu:delete")
@PostMapping(value="/delete")
public HttpResult delete(@RequestBody List<SysMenu> records) {
return HttpResult.ok(sysMenuService.delete(records));
}
@RequiresPermissions("sys:menu:view")
@GetMapping(value="/findNavTree")
public HttpResult findNavTree(@RequestParam String userName) {
return HttpResult.ok(sysMenuService.findTree(userName, 1));
}
@RequiresPermissions("sys:menu:view")
@GetMapping(value="/findMenuTree")
public HttpResult findMenuTree() {
return HttpResult.ok(sysMenuService.findTree(null, 0));
}
}测试效果
启动服务，通过Swagger分别使用超级管理员和测试人员角色账户访问接口，发现admin可以正常访问，无权限的账户访问返回如下权限验证失败信息。
{
"timestamp": "2018-11-19T07:58:21.532+0000",
"status": 500,
"error": "Internal Server Error",
"message": "Subject does not have permission [sys:menu:view]",
"path": "/menu/findMenuTree"
}原理剖析
首先在Shiro配置的时候，我们配置了一个 AuthorizationAttributeSourceAdvisor 类。
/**
* Shiro生命周期处理器
*/
@Bean
public LifecycleBeanPostProcessor lifecycleBeanPostProcessor() {
return new LifecycleBeanPostProcessor();
}
/**
* 开启Shiro的注解(如@RequiresRoles,@RequiresPermissions),需借助SpringAOP扫描使用Shiro注解的类,并在必要时进行安全逻辑验证
* 配置以下两个bean(DefaultAdvisorAutoProxyCreator(可选)和AuthorizationAttributeSourceAdvisor)即可实现此功能
*/
@Bean
@DependsOn({"lifecycleBeanPostProcessor"})
public DefaultAdvisorAutoProxyCreator advisorAutoProxyCreator() {
DefaultAdvisorAutoProxyCreator advisorAutoProxyCreator = new DefaultAdvisorAutoProxyCreator();
advisorAutoProxyCreator.setProxyTargetClass(true);
return advisorAutoProxyCreator;
}
@Bean
public AuthorizationAttributeSourceAdvisor authorizationAttributeSourceAdvisor() {
AuthorizationAttributeSourceAdvisor authorizationAttributeSourceAdvisor = new AuthorizationAttributeSourceAdvisor();
authorizationAttributeSourceAdvisor.setSecurityManager(securityManager());
return authorizationAttributeSourceAdvisor;
}在 AuthorizationAttributeSourceAdvisor 类中，我们看到了有关五个权限注解的信息，以及关联一个拦截器 AopAllianceAnnotationsAuthorizingMethodInterceptor。
public class AuthorizationAttributeSourceAdvisor extends StaticMethodMatcherPointcutAdvisor {private static final Class<? extends Annotation>[] AUTHZ_ANNOTATION_CLASSES = new Class[] {
RequiresPermissions.class, RequiresRoles.class,
RequiresUser.class, RequiresGuest.class, RequiresAuthentication.class
};
...
public AuthorizationAttributeSourceAdvisor() {
setAdvice(new AopAllianceAnnotationsAuthorizingMethodInterceptor());
}
}在 AopAllianceAnnotationsAuthorizingMethodInterceptor 中，我们看到了关联了五种权限控制注解对象的拦截器，这样在添加了权限注解的方法被调用时，就会被对应的拦截器拦截，并进行相关的权限验证。
public class AopAllianceAnnotationsAuthorizingMethodInterceptor
extends AnnotationsAuthorizingMethodInterceptor implements MethodInterceptor {
public AopAllianceAnnotationsAuthorizingMethodInterceptor() {
List<AuthorizingAnnotationMethodInterceptor> interceptors =
new ArrayList<AuthorizingAnnotationMethodInterceptor>(5);
//use a Spring-specific Annotation resolver - Spring's AnnotationUtils is nicer than the
//raw JDK resolution process.
AnnotationResolver resolver = new SpringAnnotationResolver();
//we can re-use the same resolver instance - it does not retain state:
interceptors.add(new RoleAnnotationMethodInterceptor(resolver));
interceptors.add(new PermissionAnnotationMethodInterceptor(resolver));
interceptors.add(new AuthenticatedAnnotationMethodInterceptor(resolver));
interceptors.add(new UserAnnotationMethodInterceptor(resolver));
interceptors.add(new GuestAnnotationMethodInterceptor(resolver));
setMethodInterceptors(interceptors);
}接口被调用时，AOP拦截器 AopAllianceAnnotationsAuthorizingMethodInterceptor 的invoke方法被调用。
public Object invoke(MethodInvocation methodInvocation) throws Throwable {
org.apache.shiro.aop.MethodInvocation mi = createMethodInvocation(methodInvocation);
return super.invoke(mi);
}调用父类 AuthorizingMethodInterceptor 的 invoke 方法。
public Object invoke(MethodInvocation methodInvocation) throws Throwable {
assertAuthorized(methodInvocation);
return methodInvocation.proceed();
}调用 AopAllianceAnnotationsAuthorizingMethodInterceptor 的 assertAuthorized 方法。
protected void assertAuthorized(MethodInvocation methodInvocation) throws AuthorizationException {
//default implementation just ensures no deny votes are cast:
Collection<AuthorizingAnnotationMethodInterceptor> aamis = getMethodInterceptors();
if (aamis != null && !aamis.isEmpty()) {
for (AuthorizingAnnotationMethodInterceptor aami : aamis) {
if (aami.supports(methodInvocation)) {
aami.assertAuthorized(methodInvocation);
}
}
}
}调用 AuthorizingAnnotationMethodInterceptor 的 assertAuthorized 方法。
public void assertAuthorized(MethodInvocation mi) throws AuthorizationException {
try {
((AuthorizingAnnotationHandler)getHandler()).assertAuthorized(getAnnotation(mi));
}
catch(AuthorizationException ae) {
...
}
}调用 PermissionAnnotationHandler 的 assertAuthorized 方法。
public void assertAuthorized(Annotation a) throws AuthorizationException {
if (!(a instanceof RequiresPermissions)) return;
RequiresPermissions rpAnnotation = (RequiresPermissions) a;
String[] perms = getAnnotationValue(a);
Subject subject = getSubject();
if (perms.length == 1) {
subject.checkPermission(perms[0]);
return;
}
...
}调用 DelegatingSubject 的 checkPermission方法。
public void checkPermission(String permission) throws AuthorizationException {
assertAuthzCheckPossible();
securityManager.checkPermission(getPrincipals(), permission);
}调用 AuthorizingSecurityManager 的 checkPermission方法。
public void checkPermission(PrincipalCollection principals, String permission) throws AuthorizationException {
this.authorizer.checkPermission(principals, permission);
}调用 ModularRealmAuthorizer 的 checkPermission方法。
public void checkPermission(PrincipalCollection principals, String permission) throws AuthorizationException {
assertRealmsConfigured();
if (!isPermitted(principals, permission)) {
throw new UnauthorizedException("Subject does not have permission [" + permission + "]");
}
} public boolean isPermitted(PrincipalCollection principals, String permission) {
assertRealmsConfigured();
for (Realm realm : getRealms()) {
if (!(realm instanceof Authorizer)) continue;
if (((Authorizer) realm).isPermitted(principals, permission)) {
return true;
}
}
return false;
}调用 AuthorizingRealm 的 isPermitted方法。
public boolean isPermitted(PrincipalCollection principals, String permission) {
Permission p = getPermissionResolver().resolvePermission(permission);
return isPermitted(principals, p);
} public boolean isPermitted(PrincipalCollection principals, Permission permission) {
AuthorizationInfo info = getAuthorizationInfo(principals);
return isPermitted(permission, info);
} protected AuthorizationInfo getAuthorizationInfo(PrincipalCollection principals) {
...
if (info == null) {
// Call template method if the info was not found in a cache
info = doGetAuthorizationInfo(principals);
...
}
return info;
}调用我们自定义的 OAuth2Realm 的 doGetAuthorizationInfo 方法，也是返回自定义权限验证的逻辑。
/**
* 授权(接口保护，验证接口调用权限时调用)
*/
@Override
protected AuthorizationInfo doGetAuthorizationInfo(PrincipalCollection principals) {
SysUser user = (SysUser)principals.getPrimaryPrincipal();
// 用户权限列表，根据用户拥有的权限标识与如 @permission标注的接口对比，决定是否可以调用接口
Set<String> permsSet = sysUserService.findPermissions(user.getName());
SimpleAuthorizationInfo info = new SimpleAuthorizationInfo();
info.setStringPermissions(permsSet);
return info;
}AuthorizingRealm 查询到用户权限信息，将注解权限值跟用户权限信息列表进行匹配，决定权限验证是否通过。
protected boolean isPermitted(Permission permission, AuthorizationInfo info) {
Collection<Permission> perms = getPermissions(info);
if (perms != null && !perms.isEmpty()) {
for (Permission perm : perms) {
if (perm.implies(permission)) {
return true;
}
}
}
return false;
}到这里，关于Shiro注解式权限控制方案的配置和执行流程就剖析的差不多了。