相信side對(duì)Acegi的擴(kuò)展會(huì)給你耳目一新的感覺,提供完整的擴(kuò)展功能,管理界面,中文注釋和靠近企業(yè)的安全策略。side只對(duì)Acegi不符合企業(yè)應(yīng)用需要的功能進(jìn)行擴(kuò)展,盡量不改動(dòng)其余部分來實(shí)現(xiàn)全套權(quán)限管理功能,以求能更好地適應(yīng)Acegi升級(jí)。

 

3.1 基于角色的權(quán)限控制(RBAC)

    Acegi 自帶的 sample 表設(shè)計(jì)很簡單: users表{username,password,enabled} authorities表{username,authority},這樣簡單的設(shè)計(jì)無法適應(yīng)復(fù)雜的權(quán)限需求,故SpringSide選用RBAC模型對(duì)權(quán)限控制數(shù)據(jù)庫表進(jìn)行擴(kuò)展。 RBAC引入了ROLE的概念,使User(用戶)和Permission(權(quán)限)分離,一個(gè)用戶擁有多個(gè)角色,一個(gè)角色擁有有多個(gè)相應(yīng)的權(quán)限,從而減少了權(quán)限管理的復(fù)雜度,可更靈活地支持安全策略。

    同時(shí),我們也引入了resource(資源)的概念,一個(gè)資源對(duì)應(yīng)多個(gè)權(quán)限，資源分為ACL,URL,和FUNTION三種。注意，URL和FUNTION的權(quán)限命名需要以AUTH_開頭才會(huì)有資格參加投票, 同樣的ACL權(quán)限命名需要ACL_開頭。

3.2 管理和使用EhCache

3.2.1 設(shè)立緩存

在SpringSide里的 Acegi 擴(kuò)展使用 EhCache 就作為一種緩存解決方案,以緩存用戶和資源的信息和相對(duì)應(yīng)的權(quán)限信息。

首先需要一個(gè)在classpath的 ehcache.xml 文件，用于配置 EhCache。

<ehcache>

       <defaultCache

            maxElementsInMemory="10000"

            eternal="false"

            overflowToDisk="true"

            timeToIdleSeconds="0"

            timeToLiveSeconds="0"

            diskPersistent="false"

           diskExpiryThreadIntervalSeconds= "120"/> 

    <!-- acegi cache-->

    <cache name="userCache"

           maxElementsInMemory="10000"

           eternal="true"

          overflowToDisk= "true"/>

    <!-- acegi cache-->   

    <cache name="resourceCache"

           maxElementsInMemory="10000"

           eternal="true"

           overflowToDisk="true"/>

</ehcache>

     maxElementsInMemory設(shè)定了允許在Cache中存放的數(shù)據(jù)數(shù)目，eternal設(shè)定Cache是否會(huì)過期，overflowToDisk設(shè)定內(nèi)存不足的時(shí)候緩存到硬盤，timeToIdleSeconds和timeToLiveSeconds設(shè)定緩存游離時(shí)間和生存時(shí)間，diskExpiryThreadIntervalSeconds設(shè)定緩存在硬盤上的生存時(shí)間，注意當(dāng)eternal="true"時(shí)，timeToIdleSeconds，timeToLiveSeconds和diskExpiryThreadIntervalSeconds都是無效的。

<defaultCache>是除制定的Cache外其余所有Cache的設(shè)置，針對(duì)Acegi 的情況, 專門設(shè)置了userCache和resourceCache，都設(shè)為永不過期。在applicationContext-acegi-security.xml中相應(yīng)的調(diào)用是

<bean id="userCacheBackend" class="org.springframework.cache.ehcache.EhCacheFactoryBean">

        <property name="cacheManager" ref="cacheManager"/>

        <property name="cacheName" value="  userCache"/>

    </bean>

    <bean id="userCache" class="org.acegisecurity.providers.dao.cache.EhCacheBasedUserCache" autowire="byName">

        <property name="cache" ref="userCacheBackend"/>

    </bean>

    <bean id="resourceCacheBackend" class="org.springframework.cache.ehcache.EhCacheFactoryBean">

        <property name="cacheManager" ref="cacheManager"/>

        <property name="cacheName" value="  resourceCache"/>

    </bean>

    <bean id="resourceCache" class="org.springside.modules.security.service.acegi.cache.ResourceCache" autowire="byName">

        <property name="cache" ref="resourceCacheBackend"/>

    </bean>

<bean id="cacheManager" class="org.springframework.cache.ehcache.EhCacheManagerFactoryBean"/>

"cacheName" 就是設(shè)定在ehcache.xml 中相應(yīng)Cache的名稱。

userCache使用的是Acegi 的EhCacheBasedUserCache(實(shí)現(xiàn)了UserCache接口), resourceCache是SpringSide的擴(kuò)展類

public interface UserCache   {

    public UserDetails getUserFromCache   (String username);

    public void putUserInCache   (UserDetails user);

    public void removeUserFromCache   (String username);

}

public class ResourceCache   {

    public ResourceDetails getAuthorityFromCache   (String resString) {...   }

    public void putAuthorityInCache   (ResourceDetails resourceDetails) {...  }

    public void removeAuthorityFromCache   (String resString) {... }

    public List getUrlResStrings() {... }

    public List getFunctions() {.. }

}

UserCache 就是通過EhCache對(duì)UserDetails 進(jìn)行緩存管理, 而ResourceCache 是對(duì)ResourceDetails 類進(jìn)行緩存管理

public interface UserDetails   extends Serializable {

    public boolean isAccountNonExpired();

    public boolean isAccountNonLocked();

    public GrantedAuthority[] getAuthorities();

    public boolean isCredentialsNonExpired();

    public boolean isEnabled();

    public String getPassword();

    public String getUsername();

}

public interface ResourceDetails   extends Serializable {

    public String getResString();

    public String getResType();

    public GrantedAuthority[] getAuthorities();

}

UserDetails 包含用戶信息和相應(yīng)的權(quán)限，ResourceDetails 包含資源信息和相應(yīng)的權(quán)限。

public interface GrantedAuthority     {

    public String getAuthority   ();

}

     GrantedAuthority 就是權(quán)限信息，在Acegi 的 sample 里GrantedAuthority 的信息如ROLE_USER, ROLE_SUPERVISOR, ACL_CONTACT_DELETE, ACL_CONTACT_ADMIN等等，網(wǎng)上也有很多例子把角色作為GrantedAuthority ，但事實(shí)上看看ACL 就知道， Acegi本身根本就沒有角色這個(gè)概念，GrantedAuthority 包含的信息應(yīng)該是權(quán)限，對(duì)于非ACL的權(quán)限用 AUTH_ 開頭更為合理, 如SpringSide里的 AUTH_ADMIN_LOGIN, AUTH_BOOK_MANAGE 等等。

3.2.2 管理緩存

     使用AcegiCacheManager對(duì)userCache和resourceCache進(jìn)行統(tǒng)一緩存管理。當(dāng)在后臺(tái)對(duì)用戶信息進(jìn)行修改或賦權(quán)的時(shí)候, 在更新數(shù)據(jù)庫同時(shí)就會(huì)調(diào)用acegiCacheManager相應(yīng)方法, 從數(shù)據(jù)庫中讀取數(shù)據(jù)并替換cache中相應(yīng)部分,使cache與數(shù)據(jù)庫同步。

public class AcegiCacheManager extends BaseService {

    private ResourceCache resourceCache   ;

    private UserCache userCache   ;

    /**

     * 修改User時(shí)更改userCache  

     */ 

    public void modifyUserInCache   (User user, String orgUsername) {...    }

    /**

     * 修改Resource時(shí)更改resourceCache  

     */ 

    public void modifyResourceInCache   (Resource resource, String orgResourcename) {...    }

    /**

     *   修改權(quán)限時(shí)同時(shí)修改userCache和resourceCache

     */ 

    public void modifyPermiInCache   (Permission permi, String orgPerminame) {...  }

    /**

     * User授予角色時(shí)更改userCache  

     */

    public void authRoleInCache   (User user) {...    }

    /**

     * Role授予權(quán)限時(shí)更改userCache和resourceCache  

     */ 

    public void authPermissionInCache   (Role role) {...  }

    /**

     * Permissioni授予資源時(shí)更改resourceCache  

     */ 

    public void authResourceInCache   (Permission permi) {...  }

    /**

     *   初始化userCache

     */ 

    public void initUserCache   () {...  }

    /**

     *   初始化resourceCache

     */ 

    public void initResourceCache   () {... }

    /**

     *  獲取所有的url資源

     */ 

    public List getUrlResStrings   () {...  }

    /**

     * 獲取所有的Funtion資源  

     */ 

    public List getFunctions   () {...  }

    /**

     * 根據(jù)資源串獲取資源  

     */ 

    public ResourceDetails getAuthorityFromCache   (String resString) {...  }

  

 ......





}

 

3.3 資源權(quán)限定義擴(kuò)展

     Acegi給出的sample里,資源權(quán)限對(duì)照關(guān)系是配置在xml中的,試想一下如果你的企業(yè)安全應(yīng)用有500個(gè)用戶,100個(gè)角色權(quán)限的時(shí)候,維護(hù)這個(gè)xml將是個(gè)繁重?zé)o比的工作,如何動(dòng)態(tài)更改用戶權(quán)限更是個(gè)頭痛的問題。

   <bean id="contactManagerSecurity" class="org.acegisecurity.intercept.method.aopalliance.MethodSecurityInterceptor">

      <property name="authenticationManager"><ref bean="authenticationManager"/></property>

      <property name="accessDecisionManager"><ref local="businessAccessDecisionManager"/></property>

      <property name="afterInvocationManager"><ref local="afterInvocationManager"/></property>

      <property name="objectDefinitionSource">

         <value>

            sample.contact.ContactManager.create=ROLE_USER

            sample.contact.ContactManager.getAllRecipients=ROLE_USER

            sample.contact.ContactManager.getAll=ROLE_USER,AFTER_ACL_COLLECTION_READ

            sample.contact.ContactManager.getById=ROLE_USER,AFTER_ACL_READ

            sample.contact.ContactManager.delete=ACL_CONTACT_DELETE

            sample.contact.ContactManager.deletePermission=ACL_CONTACT_ADMIN

            sample.contact.ContactManager.addPermission=ACL_CONTACT_ADMIN

         </value>

      </property>

   </bean>

  <bean id="filterInvocationInterceptor" class="org.acegisecurity.intercept.web.FilterSecurityInterceptor">

      <property name="authenticationManager"><ref bean="authenticationManager"/></property>

      <property name="accessDecisionManager"><ref local="httpRequestAccessDecisionManager"/></property>

      <property name="objectDefinitionSource">

         <value>

       CONVERT_URL_TO_LOWERCASE_BEFORE_COMPARISON

       PATTERN_TYPE_APACHE_ANT

       /index.jsp=ROLE_ANONYMOUS,ROLE_USER

       /hello.htm=ROLE_ANONYMOUS,ROLE_USER

       /logoff.jsp=ROLE_ANONYMOUS,ROLE_USER

       /switchuser.jsp=ROLE_SUPERVISOR

       /j_acegi_switch_user=ROLE_SUPERVISOR

       /acegilogin.jsp*=ROLE_ANONYMOUS,ROLE_USER

       /**=ROLE_USER

         </value>

      </property>

   </bean>

 對(duì)如此不Pragmatic的做法,SpringSide進(jìn)行了擴(kuò)展, 讓Acegi 能動(dòng)態(tài)讀取數(shù)據(jù)庫中的權(quán)限資源關(guān)系。

3.3.1 Aop Invocation Authorization

    <bean id="methodSecurityInterceptor" class="org.acegisecurity.intercept.method.aopalliance.MethodSecurityInterceptor">

        <property name="authenticationManager" ref="authenticationManager"/>

        <property name="accessDecisionManager" ref="httpRequestAccessDecisionManager"/>

        <property name="objectDefinitionSource" ref="methodDefinitionSource"/>

    </bean>

    <bean id="methodDefinitionSource" class="org.springside.security.service.acegi.DBMethodDefinitionSource">

        <property name="acegiCacheManager" ref="acegiCacheManager"/>

    </bean>

     研究下Aceig的源碼,ObjectDefinitionSource的實(shí)際作用是返回一個(gè)ConfigAttributeDefinition對(duì)象，而Acegi Sample 的方式是用MethodDefinitionSourceEditor把xml中的文本Function資源權(quán)限對(duì)應(yīng)關(guān)系信息加載到MethodDefinitionMap ( MethodDefinitionSource 的實(shí)現(xiàn)類 )中, 再組成ConfigAttributeDefinition，而我們的擴(kuò)展目標(biāo)是從緩存中讀取信息來組成ConfigAttributeDefinition。

     MethodSecurityInterceptor是通過調(diào)用AbstractMethodDefinitionSource的lookupAttributes(method)方法獲取ConfigAttributeDefinition。所以我們需要實(shí)現(xiàn)自己的ObjectDefinitionSource，繼承AbstractMethodDefinitionSource并實(shí)現(xiàn)其lookupAttributes方法,從緩存中讀取資源權(quán)限對(duì)應(yīng)關(guān)系組成并返回ConfigAttributeDefinition即可。SpringSide中的DBMethodDefinitionSource類的部分實(shí)現(xiàn)如下 :

public class DBMethodDefinitionSource extends AbstractMethodDefinitionSource {

......

    protected ConfigAttributeDefinition lookupAttributes(Method mi) {

        Assert.notNull(mi, "lookupAttrubutes in the DBMethodDefinitionSource is null");

        String methodString = mi.getDeclaringClass().getName() + "." + mi.getName();

        if (!acegiCacheManager.isCacheInitialized()) {

            //初始化Cache

            acegiCacheManager.initResourceCache();

        }

        //獲取所有的function

        List methodStrings = acegiCacheManager.getFunctions();

        Set auths = new HashSet();

        //取權(quán)限的合集

        for (Iterator iter = methodStrings.iterator(); iter.hasNext();) {

            String mappedName = (String) iter.next();

            if (methodString.equals(mappedName)

                    || isMatch(methodString, mappedName)) {

                ResourceDetails resourceDetails = acegiCacheManager.getAuthorityFromCache(mappedName);

                if (resourceDetails == null) {

                    break;

                }

                GrantedAuthority[] authorities = resourceDetails.getAuthorities();

                if (authorities == null || authorities.length == 0) {

                    break;

                }

                auths.addAll(Arrays.asList(authorities));

            }

        }

        if (auths.size() == 0)

            return null;

        ConfigAttributeEditor configAttrEditor = new ConfigAttributeEditor();

        String authoritiesStr = " ";

        for (Iterator iter = auths.iterator(); iter.hasNext();) {

            GrantedAuthority authority = (GrantedAuthority) iter.next();

            authoritiesStr += authority.getAuthority() + ",";

        }

        String authStr = authoritiesStr.substring(0, authoritiesStr.length() - 1);

        configAttrEditor.setAsText(authStr);

       //組裝并返回ConfigAttributeDefinition

        return (ConfigAttributeDefinition) configAttrEditor.getValue();

    }

    ......

}

要注意幾點(diǎn)的是:
1) 初始化Cache是比較浪費(fèi)資源的，所以SpringSide中除第一次訪問外的Cache的更新是針對(duì)性更新。

2) 因?yàn)閙ethod采用了匹配方式(詳見 isMatch() 方法) , 即對(duì)于*Book和save*這兩個(gè)資源來說，只要當(dāng)前訪問方法是Book結(jié)尾或以save開頭都算匹配得上，所以應(yīng)該取這些能匹配上的資源的相對(duì)應(yīng)的權(quán)限的合集。

3) 使用ConfigAttributeEditor 能更方便地組裝ConfigAttributeDefinition。

3.3.2 Filter Invocation Authorization

    <bean id="filterInvocationInterceptor" class="org.acegisecurity.intercept.web.FilterSecurityInterceptor">

        <property name="authenticationManager" ref="authenticationManager"/>

        <property name="accessDecisionManager" ref="httpRequestAccessDecisionManager"/>

        <property name="objectDefinitionSource" ref="filterDefinitionSource"/>

    </bean>



    <bean id="filterDefinitionSource" class="org.springside.security.service.acegi.DBFilterInvocationDefinitionSource">

        <property name="convertUrlToLowercaseBeforeComparison" value="true"/>

        <property name="useAntPath" value="true"/>

        <property name="acegiCacheManager" ref="acegiCacheManager"/>

    </bean>

     PathBasedFilterInvocationDefinitionMap和RegExpBasedFilterInvocationDefinitionMap都是 FilterInvocationDefinitionSource的實(shí)現(xiàn)類,當(dāng)PATTERN_TYPE_APACHE_ANT字符串匹配上時(shí)時(shí),FilterInvocationDefinitionSourceEditor 選用PathBasedFilterInvocationDefinitionMap 把xml中的文本URL資源權(quán)限對(duì)應(yīng)關(guān)系信息加載。

     FilterSecurityInterceptor通過FilterInvocationDefinitionSource的lookupAttributes(url)方法獲取ConfigAttributeDefinition。 所以，我們可以通過繼承FilterInvocationDefinitionSource的抽象類AbstractFilterInvocationDefinitionSource，并實(shí)現(xiàn)其lookupAttributes方法,從緩存中讀取URL資源權(quán)限對(duì)應(yīng)關(guān)系即可。SpringSide的DBFilterInvocationDefinitionSource類部分實(shí)現(xiàn)如下:

public class DBFilterInvocationDefinitionSource extends AbstractFilterInvocationDefinitionSource {



......

    public ConfigAttributeDefinition lookupAttributes(String url) {

        if (!acegiCacheManager.isCacheInitialized()) {

            acegiCacheManager.initResourceCache();

        }



        if (isUseAntPath()) {

            // Strip anything after a question mark symbol, as per SEC-161.

            int firstQuestionMarkIndex = url.lastIndexOf("?");

            if (firstQuestionMarkIndex != -1) {

                url = url.substring(0, firstQuestionMarkIndex);

            }

        }

        List urls = acegiCacheManager.getUrlResStrings();

        //URL資源倒敘排序

        Collections.sort(urls);

        Collections.reverse(urls);

//是否先全部轉(zhuǎn)為小寫再比較

        if (convertUrlToLowercaseBeforeComparison) {

            url = url.toLowerCase();

        }

        GrantedAuthority[] authorities = new GrantedAuthority[0];

        for (Iterator iterator = urls.iterator(); iterator.hasNext();) {

            String resString = (String) iterator.next();

            boolean matched = false;

              //可選擇使用AntPath和Perl5兩種不同匹配模式   

            if (isUseAntPath()) {

                matched = pathMatcher.match(resString, url);

            } else {

                Pattern compiledPattern;

                Perl5Compiler compiler = new Perl5Compiler();

                try {

                    compiledPattern = compiler.compile(resString,

                            Perl5Compiler.READ_ONLY_MASK);

                } catch (MalformedPatternException mpe) {

                    throw new IllegalArgumentException(

                            "Malformed regular expression: " + resString);

                }

                matched = matcher.matches(url, compiledPattern);

            }

            if (matched) {

                ResourceDetails rd = acegiCacheManager.getAuthorityFromCache(resString);

                authorities = rd.getAuthorities();

                break;

            }

        }

        if (authorities.length > 0) {

            String authoritiesStr = " ";

            for (int i = 0; i < authorities.length; i++) {

                authoritiesStr += authorities[i].getAuthority() + ",";

            }

            String authStr = authoritiesStr.substring(0, authoritiesStr

                    .length() - 1);

            ConfigAttributeEditor configAttrEditor = new ConfigAttributeEditor();

            configAttrEditor.setAsText(authStr);

            return (ConfigAttributeDefinition) configAttrEditor.getValue();

        }

        return null;

    }



......

 }

繼承AbstractFilterInvocationDefinitionSource注意幾點(diǎn)：
1)  需要先把獲取回來的URL資源按倒序派序，以達(dá)到 a/b/c/d.* 在 a/.* 之前的效果(詳見 Acegi sample 的applicationContext-acegi-security.xml 中的filterInvocationInterceptor的注釋)，為的是更具體的URL可以先匹配上，而獲取具體URL的權(quán)限，如a/b/c/d.*權(quán)限AUTH_a, AUTH_b 才可查看,  a/.* 需要權(quán)限AUTH_a 才可查看，則如果當(dāng)前用戶只擁有權(quán)限AUTH_b,則他只可以查看a/b/c/d.jsp 而不能察看a/d.jsp。

2) 基于上面的原因，故第一次匹配上的就是當(dāng)前所需權(quán)限，而不是取權(quán)限的合集。

3) 可以選用AntPath 或 Perl5 的資源匹配方式，感覺AntPath匹配方式基本足夠。

4) Filter 權(quán)限控制比較適合于較粗顆粒度的權(quán)限，如設(shè)定某個(gè)模塊下的頁面是否能訪問等，對(duì)于具體某個(gè)操作如增刪修改，是否能執(zhí)行，用Method  Invocation 會(huì)更佳些，所以注意兩個(gè)方面一起控制效果更好

 

3.4 授權(quán)操作

     RBAC模型中有不少多對(duì)多的關(guān)系，這些關(guān)系都能以一個(gè)中間表的形式來存放，而Hibernate中可以不建這中間表對(duì)應(yīng)的hbm.xml , 以資源與權(quán)限的配置為例，如下:

<hibernate-mapping package="org.springside.modules.security.domain">

    <class name="Permission" table="PERMISSIONS" dynamic-insert="true" dynamic-update="true">

        <cache usage="nonstrict-read-write"/>

        <id name="id" column="ID">

            <generator class="native"/>

        </id>

        <property name="name" column="NAME" not-null="true"/>

        <property name="descn" column="DESCN"/>

        <property name="operation" column="OPERATION"/>

        <property name="status" column="STATUS"/>

        <set name="roles" table="ROLE_PERMIS" lazy="true" inverse="true" cascade="save-update" batch-size="5">

            <key>

                <column name="PERMIS_ID" not-null="true"/>

            </key>

            <many-to-many class="Role" column="ROLE_ID" outer-join="auto"/>

        </set>

        <set name="resources" table="PERMIS_RESC" lazy="true" inverse="false" cascade="save-update" batch-size="5">

            <key>

                <column name="PERMIS_ID" not-null="true"/>

            </key>

            <many-to-many class="Resource" column="RESC_ID"/>

        </set>

    </class>

</hibernate-mapping>

<hibernate-mapping package="org.springside.modules.security.domain">

    <class name="Resource" table="RESOURCES" dynamic-insert="true" dynamic-update="true">

        <cache usage="nonstrict-read-write"/>

        <id name="id" column="ID">

            <generator class="native"/>

        </id>

        <property name="name" column="NAME" not-null="true"/>

        <property name="resType" column="RES_TYPE" not-null="true"/>

        <property name="resString" column="RES_STRING" not-null="true"/>

        <property name="descn" column="DESCN"/>

        <set name="permissions" table="PERMIS_RESC" lazy="true" inverse="true" cascade="save-update" batch-size="5">

            <key>

                <column name="RESC_ID" not-null="true"/>

            </key>

            <many-to-many class="Permission" column="PERMIS_ID" outer-join="auto"/>

        </set>

    </class>

</hibernate-mapping>

配置時(shí)注意幾點(diǎn):

1) 因?yàn)槭欠峙淠硞€(gè)權(quán)限的資源，所以權(quán)限是主控方，把inverse設(shè)為false，資源是被控方inverse設(shè)為true

2) cascade是"save-update"，千萬別配成delete

3) 只需要 permission.getResources().add(resource)， permission.getResources()..remove(resource) 即可很方便地完成授權(quán)和取消授權(quán)操作

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