Shiro源码分析之SecurityManager对象获取

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目录

• SecurityManager获取过程
  • 1.SecurityManager接口介绍
  • 2.SecurityManager实例化时序图
  • 3.源码分析
  • 4.总结

  上篇文章Shiro源码分析之获取SecurityManager工厂获取我们介绍了SecurityManager工厂的获取步骤，本文在此基础上来分析下SecurityManager对象产生的过程。

SecurityManager获取过程

1.SecurityManager接口介绍

  SecurityManager安全管理器,是Shiro的核心,继承了三个接口，其定义的方法如下

public interface SecurityManager extends Authenticator, Authorizer, SessionManager {
    // 登录
    Subject login(Subject subject, AuthenticationToken authenticationToken) throws AuthenticationException;
    // 注销
    void logout(Subject subject);
    // 获取Subject对象
    Subject createSubject(SubjectContext context);
}

本文重点不是分析SecurityManager的结构,所以此处略过。

2.SecurityManager实例化时序图

3.源码分析

3.1.AbstractFactory

public T getInstance() {
     T instance;
     // 判断是否是单例，默认就是单例
     if (isSingleton()) {
         if (this.singletonInstance == null) {
         	// 创建实例
             this.singletonInstance = createInstance();
         }
         instance = this.singletonInstance;
     } else {
         instance = createInstance();
     }
     if (instance == null) {
         String msg = "Factory 'createInstance' implementation returned a null object.";
         throw new IllegalStateException(msg);
     }
     return instance;
 }
// 模板模式  定义抽象方法，交给子类实现
protected abstract T createInstance();

3.2 IniFactorySupport

public T createInstance() {
	// 获取Ini对象 该对象在获取SecurityManager工厂的时候被实例化了
    Ini ini = resolveIni();

    T instance;

    if (CollectionUtils.isEmpty(ini)) {
        log.debug("No populated Ini available.  Creating a default instance.");
        instance = createDefaultInstance();
        if (instance == null) {
            String msg = getClass().getName() + " implementation did not return a default instance in " +
                    "the event of a null/empty Ini configuration.  This is required to support the " +
                    "Factory interface.  Please check your implementation.";
            throw new IllegalStateException(msg);
        }
    } else {
        log.debug("Creating instance from Ini [" + ini + "]");
        // 创建实例
        instance = createInstance(ini);
        if (instance == null) {
            String msg = getClass().getName() + " implementation did not return a constructed instance from " +
                    "the createInstance(Ini) method implementation.";
            throw new IllegalStateException(msg);
        }
    }

    return instance;
}
// 抽象方法 进入子类中查看
protected abstract T createInstance(Ini ini);

3.3 IniSecurityManagerFactory

protected SecurityManager createInstance(Ini ini) {
     if (CollectionUtils.isEmpty(ini)) {
         throw new NullPointerException("Ini argument cannot be null or empty.");
     }
     // 通过createSecurityManager获取实例
     SecurityManager securityManager = createSecurityManager(ini);
     if (securityManager == null) {
         String msg = SecurityManager.class + " instance cannot be null.";
         throw new ConfigurationException(msg);
     }
     return securityManager;
 }

 private SecurityManager createSecurityManager(Ini ini) {
     // 获取Ini中保存的shiro.ini文件中的section的 main信息
     Ini.Section mainSection = ini.getSection(MAIN_SECTION_NAME);
     if (CollectionUtils.isEmpty(mainSection)) {
         //try the default: 默认是 ""
         mainSection = ini.getSection(Ini.DEFAULT_SECTION_NAME);
     }
     return createSecurityManager(ini, mainSection);
 }

3.4 进入createSecurityManager方法

private SecurityManager createSecurityManager(Ini ini, Ini.Section mainSection) {
	// 创建默认的 SecurityManager和IniRealm 跳转到3.4.1
    Map<String, ?> defaults = createDefaults(ini, mainSection);
    // 绑定对象到SecurityManager对象
    Map<String, ?> objects = buildInstances(mainSection, defaults);
	// 从objects 中获取SecurityManager对象
    SecurityManager securityManager = getSecurityManagerBean();
    // 判断是否自动应用realm
    boolean autoApplyRealms = isAutoApplyRealms(securityManager);
	// 因为我们在shiro.ini中配置了users所以前面创建了IniRealm所以为true
    if (autoApplyRealms) {
        //realms and realm factory might have been created - pull them out first so we can
        //initialize the securityManager:
        Collection<Realm> realms = getRealms(objects);
        //set them on the SecurityManager
        if (!CollectionUtils.isEmpty(realms)) {
        	// 将IniRealm绑定到了SecurityManager中
            applyRealmsToSecurityManager(realms, securityManager);
        }
    }
	// 初始化Realm 跳至 3.5处
    initRealms(securityManager);

    return securityManager;
}

3.4.1 此处需要进入createDefaults查看

protected Map<String, ?> createDefaults(Ini ini, Ini.Section mainSection) {
     Map<String, Object> defaults = new LinkedHashMap<String, Object>();
	// 此处的代码 实例化了SecurityManager 对象
	// 3.4.2进入createDefaultInstance查看
     SecurityManager securityManager = createDefaultInstance();
     defaults.put(SECURITY_MANAGER_NAME, securityManager);
	// 判断ini中是否隐含的有realm 3.4.3查看
     if (shouldImplicitlyCreateRealm(ini)) {
     	// 创建realm 查看createRealm方法 3.4.4查看
         Realm realm = createRealm(ini);
         if (realm != null) {
             defaults.put(INI_REALM_NAME, realm);
         }
     }

     return defaults;
 }

3.4.2 createDefaultInstance方法

protected SecurityManager createDefaultInstance() {
	// SecurityManager模式的实现是DefaultSecurityManager实例
    return new DefaultSecurityManager();
}

3.4.3 shouldImplicitlyCreateRealm方法

protected boolean shouldImplicitlyCreateRealm(Ini ini) {
	// 返回结果的判断条件是 ini不为空同时(ini中包含roles或者users)就为true
    return !CollectionUtils.isEmpty(ini) &&
            (!CollectionUtils.isEmpty(ini.getSection(IniRealm.ROLES_SECTION_NAME)) ||
                    !CollectionUtils.isEmpty(ini.getSection(IniRealm.USERS_SECTION_NAME)));
}

3.4.4 createRealm

 protected Realm createRealm(Ini ini) {
 	// 我们可以看到实例化的是IniRealm对象
     IniRealm realm = new IniRealm(ini);
     realm.setName(INI_REALM_NAME);
     return realm;
 }

3.5 initRealms

private void initRealms(SecurityManager securityManager) {
    Collection<Realm> realms = getRealms(securityManager);
    if (!CollectionUtils.isEmpty(realms)) {
        LifecycleUtils.init(realms);
    }
}

3.6 LifecycleUtils

public static void init(Collection c) throws ShiroException {
    if (c == null || c.isEmpty()) {
        return;
    }
    for (Object o : c) {
        init(o);
    }
}

public static void init(Object o) throws ShiroException {
    if (o instanceof Initializable) {
        init((Initializable) o);
    }
}

public static void init(Initializable initializable) throws ShiroException {
    initializable.init();
}

3.7AuthorizingRealm

public final void init() {
    //trigger obtaining the authorization cache if possible
    getAvailableAuthorizationCache();
    onInit(); // 进入IniRealm中
}

3.8 IniRealm

protected void onInit() {
     // This is an in-memory realm only - no need for an additional cache when we're already
     // as memory-efficient as we can be.
     String resourcePath = getResourcePath();

     if (CollectionUtils.isEmpty(this.users) && CollectionUtils.isEmpty(this.roles)) {
         //no account data manually populated - try the resource path:
         if (StringUtils.hasText(resourcePath)) {
             log.debug("Resource path {} defined.  Creating INI instance.", resourcePath);
             Ini ini = Ini.fromResourcePath(resourcePath);
             // 核心方法进入
             processDefinitions(ini);
         } else {
             throw new IllegalStateException("No resource path was specified.  Cannot load account data.");
         }
     } else {
         if (StringUtils.hasText(resourcePath)) {
             log.warn("Users or Roles are already populated.  Resource path property will be ignored.");
         }
     }
 }

processDefinitions

private void processDefinitions(Ini ini) {
    if (CollectionUtils.isEmpty(ini)) {
        log.warn("{} defined, but the ini instance is null or empty.", getClass().getSimpleName());
        return;
    }

    Ini.Section rolesSection = ini.getSection(ROLES_SECTION_NAME);
    if (!CollectionUtils.isEmpty(rolesSection)) {
        log.debug("Discovered the [{}] section.  Processing...", ROLES_SECTION_NAME);
        // 处理角色信息
        processRoleDefinitions(rolesSection);
    }

    Ini.Section usersSection = ini.getSection(USERS_SECTION_NAME);
    if (!CollectionUtils.isEmpty(usersSection)) {
        log.debug("Discovered the [{}] section.  Processing...", USERS_SECTION_NAME);
        // 处理用户信息
        processUserDefinitions(usersSection);
    } else {
        log.info("{} defined, but there is no [{}] section defined.  This realm will not be populated with any " +
                "users and it is assumed that they will be populated programatically.  Users must be defined " +
                "for this Realm instance to be useful.", getClass().getSimpleName(), USERS_SECTION_NAME);
    }
}

3.9 TextConfigurationRealm

processRoleDefinitions

protected void processRoleDefinitions(Map<String, String> roleDefs) {
    if (roleDefs == null || roleDefs.isEmpty()) {
        return;
    }

    for (String rolename : roleDefs.keySet()) {
        String value = roleDefs.get(rolename);

        SimpleRole role = getRole(rolename);
        if (role == null) {
            role = new SimpleRole(rolename);
            // 添加角色
            add(role);
        }

        Set<Permission> permissions = PermissionUtils.resolveDelimitedPermissions(value, getPermissionResolver());
        // 添加权限
        role.setPermissions(permissions);
    }
}

processUserDefinitions

protected void processUserDefinitions(Map<String, String> userDefs) {
    if (userDefs == null || userDefs.isEmpty()) {
        return;
    }

    for (String username : userDefs.keySet()) {

        String value = userDefs.get(username);

        String[] passwordAndRolesArray = StringUtils.split(value);

        String password = passwordAndRolesArray[0];

        SimpleAccount account = getUser(username);
        if (account == null) {
            account = new SimpleAccount(username, password, getName());
            //添加账号
            add(account);
        }
        account.setCredentials(password);

        if (passwordAndRolesArray.length > 1) {
            for (int i = 1; i < passwordAndRolesArray.length; i++) {
                String rolename = passwordAndRolesArray[i];
                account.addRole(rolename);

                SimpleRole role = getRole(rolename);
                if (role != null) {
                    account.addObjectPermissions(role.getPermissions());
                }
            }
        } else {
            account.setRoles(null);
        }
    }
}

3.10 SimpleAccountRealm

protected void add(SimpleRole role) {
    roles.put(role.getName(), role);
}

 protected void add(SimpleAccount account) {
     String username = getUsername(account);
     this.users.put(username, account);
 }

最后回到createSecurityManager方法中

private SecurityManager createSecurityManager(Ini ini, Ini.Section mainSection) {
	// 创建默认的 SecurityManager和IniRealm
    Map<String, ?> defaults = createDefaults(ini, mainSection);
    // 绑定对象到SecurityManager对象
    Map<String, ?> objects = buildInstances(mainSection, defaults);
	// 从objects 中获取SecurityManager对象
    SecurityManager securityManager = getSecurityManagerBean();
    // 判断是否自动应用realm
    boolean autoApplyRealms = isAutoApplyRealms(securityManager);
	// 因为我们在shiro.ini中配置了users所以前面创建了IniRealm所以为true
    if (autoApplyRealms) {
        //realms and realm factory might have been created - pull them out first so we can
        //initialize the securityManager:
        Collection<Realm> realms = getRealms(objects);
        //set them on the SecurityManager
        if (!CollectionUtils.isEmpty(realms)) {
        	// 将IniRealm绑定到了SecurityManager中
            applyRealmsToSecurityManager(realms, securityManager);
        }
    }
	// 初始化Realm
    initRealms(securityManager);

    return securityManager;
}

初始化SecurityManager完成

4.总结

1. SecurityManager默认实例的是DefaultSecurityManager
2. 如果我们在shiro.ini配置文件配置了[Users]的话那么会自动创建IniRealm
3. 创建的IniRealm会被绑定到SecurityManager对象中，并且会将账号密码保存到SimpleAccountRealm的User集合中，认证的时候会从此对象中获取