Apache Shiro学习笔记（三）用户受权isPermitted过程

鲁春利的工做笔记，好记性不如烂笔头

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Shiro配置文件(shiro-authorize-permission.ini)

[main]
# 定义变量
# 变量名=全类名

[users]
# 用户名=密码,角色1,角色2,...,角色N
lucl=123,role1,role2
zs=123,role1

[roles]
# 角色=权限1,权限2,...,权限N
role1=user:create,user:update
role2=user:create,user:delete

单元测试

/**
 * 基于资源的访问控制
 */
@Test
public void testWhetherHasPermission () {
    // 一、获取SecurityManager工厂，此处使用Ini配置文件初始化SecurityManager
    Factory<org.apache.shiro.mgt.SecurityManager> factory = new IniSecurityManagerFactory("classpath:shiro/authorize/shiro-authorize-permission.ini");
    
    // 二、获得SecurityManager实例并绑定给SecurityUtils
    org.apache.shiro.mgt.SecurityManager securityManager = factory.getInstance();
    SecurityUtils.setSecurityManager(securityManager);
    
    // 三、获得Subject及建立用户名/密码身份验证Token（即用户身份/凭证）
    Subject subject = SecurityUtils.getSubject();

    UsernamePasswordToken token = new UsernamePasswordToken("lucl", "123");
    try{
        // 四、登陆，即身份验证
        subject.login(token);
    } catch (AuthenticationException e) {
        // 五、身份验证失败
        logger.info("用户身份验证失败");
        e.printStackTrace();
    }
    
    // 用户身份获得确认
    if (subject.isAuthenticated()) {
        logger.info("用户登陆成功。");
        /**
         * 进行权限判断
         */
        // 判断拥有权限：user:create
        Assert.assertTrue(subject.isPermitted("user:create"));
        // 判断拥有权限：user:update and user:delete
        Assert.assertTrue(subject.isPermittedAll("user:update", "user:delete"));
        // 判断没有权限：user:view
        Assert.assertFalse(subject.isPermitted("user:view"));
        
        // 断言拥有权限：user:create
        subject.checkPermission("user:create");
        // 断言拥有权限：user:delete and user:update
        subject.checkPermissions("user:delete", "user:update");
        // 断言拥有权限：user:view 失败抛出异常
        subject.checkPermissions("user:view");
    } else {
        logger.info("用户登陆失败。");
    }

    // 六、退出
    subject.logout();
}

isPermitted过程

• subject.isPermitted

package org.apache.shiro.subject.support;

public class DelegatingSubject implements Subject {
    /** hasPrincipals()判断身份信息，身份信息是在login方法登陆后赋值的 */
    public boolean isPermitted(String permission) {
        return hasPrincipals() && securityManager.isPermitted(getPrincipals(), permission);
    }
    
    public void login(AuthenticationToken token) throws AuthenticationException {
        clearRunAsIdentitiesInternal();
        /** 身份认证 */
        Subject subject = securityManager.login(this, token);

        PrincipalCollection principals;

        String host = null;

        if (subject instanceof DelegatingSubject) {
            DelegatingSubject delegating = (DelegatingSubject) subject;
            //we have to do this in case there are assumed identities - we don't want to lose the 'real' principals:
            principals = delegating.principals;
            host = delegating.host;
        } else {
            principals = subject.getPrincipals();
        }

        if (principals == null || principals.isEmpty()) {
            // 异常信息
            throw new IllegalStateException(msg);
        }
        this.principals = principals;
        this.authenticated = true;
        // 代码略
    }
}

• securityManager.isPermitted

securityManager的实现为DefaultSecurityManager，但DefaultSecurityManager无isPermitted方法。

org.apache.shiro.mgt.DefaultSecurityManager
    extends org.apache.shiro.mgt.SessionsSecurityManager
        extends org.apache.shiro.mgt.AuthorizingSecurityManager
            extends org.apache.shiro.mgt.AuthenticatingSecurityManager

• 调用AuthorizingSecurityManager的isPermitted方法
  

package org.apache.shiro.mgt;

public abstract class AuthorizingSecurityManager extends AuthenticatingSecurityManager {
    /**
     * The wrapped instance to which all of this SecurityManager authorization calls are delegated.
     * 受权的核心接口
     */
    private Authorizer authorizer;
    
    public AuthorizingSecurityManager() {
        super();
        this.authorizer = new ModularRealmAuthorizer();
    }
    
    public boolean isPermitted(PrincipalCollection principals, Permission permission) {
        return this.authorizer.isPermitted(principals, permission);
    }
    
    // 其余代码略
}

• ModularRealmAuthorizer.isPermitted方法
  

package org.apache.shiro.authz;

public class ModularRealmAuthorizer implements Authorizer, PermissionResolverAware, RolePermissionResolverAware {

    /**
     * The realms to consult during any authorization check.
     */
    protected Collection<Realm> realms;
    
    protected PermissionResolver permissionResolver;
    
    protected RolePermissionResolver rolePermissionResolver;
    
    public ModularRealmAuthorizer() {
        // 无参构造方法
    }
    
    public ModularRealmAuthorizer(Collection<Realm> realms) {
        setRealms(realms);
    }
    
    /* 权限判断 */
    public boolean isPermitted(PrincipalCollection principals, Permission permission) {
        assertRealmsConfigured();
        for (Realm realm : getRealms()) {
            if (!(realm instanceof Authorizer)) continue;
            if (((Authorizer) realm).isPermitted(principals, permission)) {
                return true;
            }
        }
        return false;
    }

}

转了一圈，具体的isPermitted仍是经过最终的realm来完成（IniRealm）

org.apache.shiro.realm.text.IniRealm
    extends org.apache.shiro.realm.text.TextConfigurationRealm
        extends org.apache.shiro.realm.SimpleAccountRealm
            extends org.apache.shiro.realm.AuthorizingRealm

• AuthorizingRealm.isPermitted被调用

package org.apache.shiro.realm;

 /**
  * An AuthorizingRealm extends the AuthenticatingRealm's capabilities by adding Authorization (access control) support. 
  * @see org.apache.shiro.authz.SimpleAuthorizationInfo
  * @since 0.2
  */
public abstract class AuthorizingRealm extends AuthenticatingRealm
        implements Authorizer, Initializable, PermissionResolverAware, RolePermissionResolverAware {

    private PermissionResolver permissionResolver;

    private RolePermissionResolver permissionRoleResolver;
    
    public AuthorizingRealm() {
        this(null, null);
    }
    
    
    public AuthorizingRealm(CacheManager cacheManager) {
        this(cacheManager, null);
    }

    public AuthorizingRealm(CredentialsMatcher matcher) {
        this(null, matcher);
    }

    public AuthorizingRealm(CacheManager cacheManager, CredentialsMatcher matcher) {
        /** super()会调用父类的无参构造方法，也就是new AuthenticatingRealm() {this(null, new SimpleCredentialsMatcher());} */
        super();
        if (cacheManager != null) setCacheManager(cacheManager);
        if (matcher != null) setCredentialsMatcher(matcher);

        this.authorizationCachingEnabled = true;
        // permissionResolver的实现类，自定义Permission时自定了也自定义了这个东西
        this.permissionResolver = new WildcardPermissionResolver();

        // 代码略
    }
    
    public boolean isPermitted(PrincipalCollection principals, String permission) {
        // WildcardPermissionResolver.resolvePermission {return new WildcardPermission(permissionString);}
        Permission p = getPermissionResolver().resolvePermission(permission);
        return isPermitted(principals, p);
    }

    public boolean isPermitted(PrincipalCollection principals, Permission permission) {
        /** 
         * getAuthorizationInfo(principals)实际返回的是SimpleAccount；
         * 若是咱们在自定义的Realm中实现了info.add("system:edit:1")，那么SimpleAccount就获取到了其拥有的权限列表：
         * 说明：也就是shiro不维护权限信息，其应该具备的权限信息是由业务系统根据实际状况来设定的
         * isPermitted会比较传入的权限字符串，是否在实际设定的权限列表中（权限列表通常根据登陆用户权限从数据库中读取并加载）
         */
        AuthorizationInfo info = getAuthorizationInfo(principals);
        return isPermitted(permission, info);
    }
    
    /** 最终的判断方法（权限集合是在Realm实现时添加的权限列表，如info.add("system:edit:1")） */
    protected boolean isPermitted(Permission permission, AuthorizationInfo info) {
        Collection<Permission> perms = getPermissions(info);
        if (perms != null && !perms.isEmpty()) {
            for (Permission perm : perms) {
                /** Permission的implies方法总算是被调用到了 */
                if (perm.implies(permission)) {
                    return true;
                }
            }
        }
        return false;
    }
    
    protected AuthorizationInfo getAuthorizationInfo(PrincipalCollection principals) {

        if (principals == null) {
            return null;
        }

        AuthorizationInfo info = null;

        // 代码略，主要实现从缓存中获取受权数据

        if (info == null) {
            // Call template method if the info was not found in a cache
            /** 这是最核心的受权实现方法，用户自定义方法通常重写该方法，实现本身的受权过程 */
            info = doGetAuthorizationInfo(principals);
            // If the info is not null and the cache has been created, then cache the authorization info.
            // 代码略，获取后从新加入缓存中
        }

        return info;
    }
    
    // 该类的doGetAuthorizationInfo方法为抽象方法，须要子类根据身份信息实现本身的受权
    protected abstract AuthorizationInfo doGetAuthorizationInfo(PrincipalCollection principals);
}

• SimpleAccountRealm.doGetAuthorizationInfo方法

package org.apache.shiro.realm;

public class SimpleAccountRealm extends AuthorizingRealm {

    // 部分代码略
    
    protected AuthorizationInfo doGetAuthorizationInfo(PrincipalCollection principals) {
        String username = getUsername(principals);
        USERS_LOCK.readLock().lock();
        try {
            return this.users.get(username);    // 返回SimpleAccount
        } finally {
            USERS_LOCK.readLock().unlock();
        }
    }
}