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  • springSecurity安全框架的学习和原理解读

    最近在公司的项目中使用了spring security框架,所以有机会来学习一下,公司的项目是使用springboot搭建 springBoot版本1.59

    spring security 版本4.2.3

       (个人理解可能会有偏差,希望有不正确之处,大家能够指出来,共同探讨交流。)

    目录

    一、Spring security框架简介

     1、简介

     2、框架原理

     3、框架的核心组件

    二、自定义安全配置的加载机制

    1、前提 基于自身业务需要

    2、WebSecurityConfiguration类

    3、AbstractSecurityBuilder类

    4、举例说明如何将一个Configurer转换为filter

    三、用户登录的验证和授权过程


    一、Spring security框架简介

         1、简介

               一个能够为基于Spring的企业应用系统提供声明式的安全訪问控制解决方式的安全框架(简单说是对访问权限进行控制嘛),应用的安全性包括用户认证(Authentication)和用户授权(Authorization)两个部分。用户认证指的是验证某个用户是否为系统中的合法主体,也就是说用户能否访问该系统。用户认证一般要求用户提供用户名和密码。系统通过校验用户名和密码来完成认证过程。用户授权指的是验证某个用户是否有权限执行某个操作。在一个系统中,不同用户所具有的权限是不同的。比如对一个文件来说,有的用户只能进行读取,而有的用户可以进行修改。一般来说,系统会为不同的用户分配不同的角色,而每个角色则对应一系列的权限。   spring security的主要核心功能为 认证和授权,所有的架构也是基于这两个核心功能去实现的。

         2、框架原理

         众所周知 想要对对Web资源进行保护,最好的办法莫过于Filter,要想对方法调用进行保护,最好的办法莫过于AOP。所以springSecurity在我们进行用户认证以及授予权限的时候,通过各种各样的拦截器来控制权限的访问,从而实现安全。
            如下为其主要过滤器  

    1.         WebAsyncManagerIntegrationFilter 
    2.         SecurityContextPersistenceFilter 
    3.         HeaderWriterFilter 
    4.         CorsFilter 
    5.         LogoutFilter
    6.         RequestCacheAwareFilter
    7.         SecurityContextHolderAwareRequestFilter
    8.         AnonymousAuthenticationFilter
    9.         SessionManagementFilter
    10.         ExceptionTranslationFilter
    11.         FilterSecurityInterceptor
    12.         UsernamePasswordAuthenticationFilter
    13.         BasicAuthenticationFilter

         3、框架的核心组件

    1.       SecurityContextHolder:提供对SecurityContext的访问
    2.       SecurityContext,:持有Authentication对象和其他可能需要的信息
    3.       AuthenticationManager 其中可以包含多个AuthenticationProvider
    4.       ProviderManager对象为AuthenticationManager接口的实现类
    5.       AuthenticationProvider 主要用来进行认证操作的类 调用其中的authenticate()方法去进行认证操作
    6.       Authentication:Spring Security方式的认证主体
    7.       GrantedAuthority:对认证主题的应用层面的授权,含当前用户的权限信息,通常使用角色表示
    8.      UserDetails:构建Authentication对象必须的信息,可以自定义,可能需要访问DB得到
    9.       UserDetailsService:通过username构建UserDetails对象,通过loadUserByUsername根据userName获取UserDetail对象 (可以在这里基于自身业务进行自定义的实现  如通过数据库,xml,缓存获取等)           

        
         

    二、自定义安全配置的加载机制

        1、前提 基于自身业务需要

    有关springSecrity安全框架的理解参考:springSecurity安全框架介绍

    自定义了一个springSecurity安全框架的配置类 继承WebSecurityConfigurerAdapter,重写其中的方法configure,但是并不清楚自定义的类是如何被加载并起到作用,这里一步步通过debug来了解其中的加载原理。

    其实在我们实现该类后,在web容器启动的过程中该类实例对象会被WebSecurityConfiguration类处理。

    @Configuration
    public class SpringSecurityConfig extends WebSecurityConfigurerAdapter {
    
        @Autowired
        private AccessDeniedHandler accessDeniedHandler;
    
        @Autowired
        private CustAuthenticationProvider custAuthenticationProvider;
    
        // roles admin allow to access /admin/**
        // roles user allow to access /user/**
        // custom 403 access denied handler
        //重写了其中的configure()方法设置了不同url的不同访问权限
        @Override
        protected void configure(HttpSecurity http) throws Exception {
            http.csrf().disable()
                    .authorizeRequests()
                    .antMatchers("/home", "/about","/img/*").permitAll()
                    .antMatchers("/admin/**","/upload/**").hasAnyRole("ADMIN")
                    .antMatchers("/order/**").hasAnyRole("USER","ADMIN")
                    .antMatchers("/room/**").hasAnyRole("USER","ADMIN")
                    .anyRequest().authenticated()
                    .and()
                    .formLogin()
                    .loginPage("/login")
                    .permitAll()
                    .and()
                    .logout()
                    .permitAll()
                    .and()
                    .exceptionHandling().accessDeniedHandler(accessDeniedHandler);
        }
    
        // create two users, admin and user
        @Autowired
        public void configureGlobal(AuthenticationManagerBuilder auth) throws Exception {
    
    //        auth.inMemoryAuthentication()
    //                .withUser("user").password("user").roles("USER")
    //                .and()
    //                .withUser("admin").password("admin").roles("ADMIN");
    
    //        auth.jdbcAuthentication()
    
            auth.authenticationProvider(custAuthenticationProvider);
        }
    

      2、WebSecurityConfiguration类

    @Configuration
    public class WebSecurityConfiguration implements ImportAware, BeanClassLoaderAware {
        private WebSecurity webSecurity;
        private Boolean debugEnabled;
        private List<SecurityConfigurer<Filter, WebSecurity>> webSecurityConfigurers;
        private ClassLoader beanClassLoader;
       
       ...省略部分代码
    
        @Bean(
            name = {"springSecurityFilterChain"}
        )
        public Filter springSecurityFilterChain() throws Exception {
            boolean hasConfigurers = this.webSecurityConfigurers != null
             && !this.webSecurityConfigurers.isEmpty();
            if(!hasConfigurers) {
                WebSecurityConfigurerAdapter adapter = (WebSecurityConfigurerAdapter)
                this.objectObjectPostProcessor
                  .postProcess(new WebSecurityConfigurerAdapter() {
                });
                this.webSecurity.apply(adapter);
            }
    
            return (Filter)this.webSecurity.build();
        }
    
      
        
        /*1、先执行该方法将我们自定义springSecurity配置实例
           (可能还有系统默认的有关安全的配置实例 ) 配置实例中含有我们自定义业务的权限控制配置信息
           放入到该对象的list数组中webSecurityConfigurers中
           使用@Value注解来将实例对象作为形参注入
         */   
     @Autowired(
            required = false
        )
        public void setFilterChainProxySecurityConfigurer(ObjectPostProcessor<Object> 
        objectPostProcessor,
       @Value("#{@autowiredWebSecurityConfigurersIgnoreParents.getWebSecurityConfigurers()}") 
      List<SecurityConfigurer<Filter, WebSecurity>> webSecurityConfigurers) 
    throws Exception {
        
        //创建一个webSecurity对象    
        this.webSecurity = (WebSecurity)objectPostProcessor.postProcess(new WebSecurity(objectPostProcessor));
            if(this.debugEnabled != null) {
                this.webSecurity.debug(this.debugEnabled.booleanValue());
            }
    
            //对所有配置类的实例进行排序
            Collections.sort(webSecurityConfigurers, WebSecurityConfiguration.AnnotationAwareOrderComparator.INSTANCE);
            Integer previousOrder = null;
            Object previousConfig = null;
    
    
            //迭代所有配置类的实例 判断其order必须唯一
            Iterator var5;
            SecurityConfigurer config;
            for(var5 = webSecurityConfigurers.iterator(); var5.hasNext(); previousConfig = config) {
                config = (SecurityConfigurer)var5.next();
                Integer order = Integer.valueOf(WebSecurityConfiguration.AnnotationAwareOrderComparator.lookupOrder(config));
                if(previousOrder != null && previousOrder.equals(order)) {
                    throw new IllegalStateException("@Order on WebSecurityConfigurers must be unique. Order of " + order + " was already used on " + previousConfig + ", so it cannot be used on " + config + " too.");
                }
    
                previousOrder = order;
            }
    
    
            //将所有的配置实例添加到创建的webSecutity对象中
            var5 = webSecurityConfigurers.iterator();
    
            while(var5.hasNext()) {
                config = (SecurityConfigurer)var5.next();
                this.webSecurity.apply(config);
            }
            //将webSercurityConfigures 实例放入该对象的webSecurityConfigurers属性中
            this.webSecurityConfigurers = webSecurityConfigurers;
        }
    
       
    }
    

      2.1、 setFilterChainProxySecurityConfigurer()方法

    @Value("#{@autowiredWebSecurityConfigurersIgnoreParents.getWebSecurityConfigurers()}") List<SecurityConfigurer<Filter, WebSecurity>> webSecurityConfigurers

       该参数webSecurityConfigurers会将所有的配置实例放入该形参中

     

    该方法中 主要执行如下

         1、创建webSecurity对象

         2、主要检验了配置实例的order顺序(order唯一 否则会报错)

         3、将所有的配置实例存放进入到webSecurity对象中,其中配置实例中含有我们自定义业务的权限控制配置信息

    2.2、springSecurityFilterChain()方法

       调用springSecurityFilterChain()方法,这个方法会判断我们上一个方法中有没有获取到webSecurityConfigurers,没有的话这边会创建一个WebSecurityConfigurerAdapter实例,并追加到websecurity中。接着调用websecurity的build方法。实际调用的是websecurity的父类AbstractSecurityBuilder的build方法 ,最终返回一个名称为springSecurityFilterChain的过滤器链。里面有众多Filter(springSecurity其实就是依靠很多的Filter来拦截url从而实现权限的控制的安全框架)

    3、AbstractSecurityBuilder类

    public abstract class AbstractSecurityBuilder<O> implements SecurityBuilder<O> {
        private AtomicBoolean building = new AtomicBoolean();
        private O object;
    
      
    
        //调用build方法来返回过滤器链,还是调用SecurityBuilder的dobuild()方法
    
        public final O build() throws Exception {
            if(this.building.compareAndSet(false, true)) {
                this.object = this.doBuild();
                return this.object;
            } else {
                throw new AlreadyBuiltException("This object has already been built");
            }
        }
    
       //...省略部分代码
    }

      3.1 调用子类的doBuild()方法

    public abstract class AbstractConfiguredSecurityBuilder<O, B extends SecurityBuilder<O>> extends AbstractSecurityBuilder<O> {
        private final Log logger;
        private final LinkedHashMap<Class<? extends SecurityConfigurer<O, B>>, List<SecurityConfigurer<O, B>>> configurers;
        private final List<SecurityConfigurer<O, B>> configurersAddedInInitializing;
        private final Map<Class<? extends Object>, Object> sharedObjects;
        private final boolean allowConfigurersOfSameType;
        private AbstractConfiguredSecurityBuilder.BuildState buildState;
        private ObjectPostProcessor<Object> objectPostProcessor;
    
    
        //doBuild()核心方法 init(),configure(),perFormBuild()
        protected final O doBuild() throws Exception {
            LinkedHashMap var1 = this.configurers;
            synchronized(this.configurers) {
                this.buildState = AbstractConfiguredSecurityBuilder.BuildState.INITIALIZING;
                this.beforeInit();
                this.init();
                this.buildState = AbstractConfiguredSecurityBuilder.BuildState.CONFIGURING;
                this.beforeConfigure();
                this.configure();
                this.buildState = AbstractConfiguredSecurityBuilder.BuildState.BUILDING;
                O result = this.performBuild();
                this.buildState = AbstractConfiguredSecurityBuilder.BuildState.BUILT;
                return result;
            }
        }
    
        protected abstract O performBuild() throws Exception;
        
        //调用init方法 调用配置类WebSecurityConfigurerAdapter的init()方法
        private void init() throws Exception {
            Collection<SecurityConfigurer<O, B>> configurers = this.getConfigurers();
            Iterator var2 = configurers.iterator();
    
            SecurityConfigurer configurer;
            while(var2.hasNext()) {
                configurer = (SecurityConfigurer)var2.next();
                configurer.init(this);
            }
    
            var2 = this.configurersAddedInInitializing.iterator();
    
            while(var2.hasNext()) {
                configurer = (SecurityConfigurer)var2.next();
                configurer.init(this);
            }
    
        }
    
        private void configure() throws Exception {
            Collection<SecurityConfigurer<O, B>> configurers = this.getConfigurers();
            Iterator var2 = configurers.iterator();
    
            while(var2.hasNext()) {
                SecurityConfigurer<O, B> configurer = (SecurityConfigurer)var2.next();
                configurer.configure(this);
            }
    
        }
    
        private Collection<SecurityConfigurer<O, B>> getConfigurers() {
            List<SecurityConfigurer<O, B>> result = new ArrayList();
            Iterator var2 = this.configurers.values().iterator();
    
            while(var2.hasNext()) {
                List<SecurityConfigurer<O, B>> configs = (List)var2.next();
                result.addAll(configs);
            }
    
            return result;
        }
    
        //...省略部分代码
    }
    

    3.2 先调用本类的init()方法

    build过程主要分三步,init->configure->peformBuild 

    • 1  init方法做了两件事,一个就是调用getHttp()方法获取一个http实例,并通过web.addSecurityFilterChainBuilder方法把获取到的实例赋值给WebSecurity的securityFilterChainBuilders属性,这个属性在我们执行build的时候会用到,第二个就是为WebSecurity追加了一个postBuildAction,在build都完成后从http中拿出FilterSecurityInterceptor对象并赋值给WebSecurity。 
    • 2  getHttp()方法,这个方法在当我们使用默认配置时(大多数情况下)会为我们追加各种SecurityConfigurer的具体实现类到httpSecurity中,如exceptionHandling()方法会追加一个ExceptionHandlingConfigurer,sessionManagement()方法会追加一个SessionManagementConfigurer,securityContext()方法会追加一个SecurityContextConfigurer对象,这些SecurityConfigurer的具体实现类最终会为我们配置各种具体的filter。
    • 3 另外getHttp()方法的最后会调用configure(http),这个方法也是我们继承WebSecurityConfigurerAdapter类后最可能会重写的方法 。
    • 4 configure(HttpSecurity http)方法,默认的configure(HttpSecurity http)方法继续向httpSecurity类中追加SecurityConfigurer的具体实现类,如authorizeRequests()方法追加一个ExpressionUrlAuthorizationConfigurer,formLogin()方法追加一个FormLoginConfigurer。 其中ExpressionUrlAuthorizationConfigurer这个实现类比较重要,因为他会给我们创建一个非常重要的对象FilterSecurityInterceptor对象,FormLoginConfigurer对象比较简单,但是也会为我们提供一个在安全认证过程中经常用到会用的一个Filter:UsernamePasswordAuthenticationFilter。 

    以上三个方法就是WebSecurityConfigurerAdapter类中init方法的主要逻辑,

    public abstract class WebSecurityConfigurerAdapter implements 
       WebSecurityConfigurer<WebSecurity> {
    
        public void init(final WebSecurity web) throws Exception {
            final HttpSecurity http = this.getHttp();
            web.addSecurityFilterChainBuilder(http).postBuildAction(new Runnable() {
                public void run() {
                    FilterSecurityInterceptor securityInterceptor = (FilterSecurityInterceptor)http.getSharedObject(FilterSecurityInterceptor.class);
                    web.securityInterceptor(securityInterceptor);
                }
            });
        }
    
    
     protected final HttpSecurity getHttp() throws Exception {
            if(this.http != null) {
                return this.http;
            } else {
                DefaultAuthenticationEventPublisher eventPublisher = (DefaultAuthenticationEventPublisher)this.objectPostProcessor.postProcess(new DefaultAuthenticationEventPublisher());
           
    
    //添加认证的事件的发布者
    this.localConfigureAuthenticationBldr.authenticationEventPublisher(eventPublisher);
    //获取AuthenticationManager对象其中一至多个进行认证处理的对象实例,后面会进行讲解          
    AuthenticationManager authenticationManager = this.authenticationManager();
                this.authenticationBuilder.parentAuthenticationManager(authenticationManager);
                Map<Class<? extends Object>, Object> sharedObjects = this.createSharedObjects();
                this.http = new HttpSecurity(this.objectPostProcessor, this.authenticationBuilder, sharedObjects);
                if(!this.disableDefaults) {
                    ((HttpSecurity)((DefaultLoginPageConfigurer)((HttpSecurity)((HttpSecurity)((HttpSecurity)((HttpSecurity)((HttpSecurity)((HttpSecurity)((HttpSecurity)((HttpSecurity)this.http.csrf().and()).addFilter(new WebAsyncManagerIntegrationFilter()).exceptionHandling().and()).headers().and()).sessionManagement().and()).securityContext().and()).requestCache().and()).anonymous().and()).servletApi().and()).apply(new DefaultLoginPageConfigurer())).and()).logout();
                    ClassLoader classLoader = this.context.getClassLoader();
                    List<AbstractHttpConfigurer> defaultHttpConfigurers = SpringFactoriesLoader.loadFactories(AbstractHttpConfigurer.class, classLoader);
                    Iterator var6 = defaultHttpConfigurers.iterator();
    
                    while(var6.hasNext()) {
                        AbstractHttpConfigurer configurer = (AbstractHttpConfigurer)var6.next();
                        this.http.apply(configurer);
                    }
                }
    
                //最终调用我们的继承的WebSecurityConfigurerAdapter中重写的configure()
                //将我们业务相关的权限配置规则信息进行初始化操作
                this.configure(this.http);
                return this.http;
            }
        }
    
    
     protected AuthenticationManager authenticationManager() throws Exception {
            if(!this.authenticationManagerInitialized) {
                this.configure(this.localConfigureAuthenticationBldr);
                if(this.disableLocalConfigureAuthenticationBldr) {
                    this.authenticationManager = this.authenticationConfiguration.getAuthenticationManager();
                } else {
                    this.authenticationManager = (AuthenticationManager)this.localConfigureAuthenticationBldr.build();
                }
    
                this.authenticationManagerInitialized = true;
            }
    
            return this.authenticationManager;
        }
    
    
    
    }

    3.3、第二步configure

    • configure方法最终也调用到了WebSecurityConfigurerAdapter的configure(WebSecurity web)方法,默认实现中这个是一个空方法,具体应用中也经常重写这个方法来实现特定需求。 

    3.4、第三步 peformBuild

    • 具体的实现逻辑在WebSecurity类中 
    • 这个方法中最主要的任务就是遍历securityFilterChainBuilders属性中的SecurityBuilder对象,并调用他的build方法。 
      这个securityFilterChainBuilders属性我们前面也有提到过,就是在WebSecurityConfigurerAdapter类的init方法中获取http后赋值给了WebSecurity。因此这个地方就是调用httpSecurity的build方法。
    •  httpSecurity的build方式向其中追加一个个过滤器
    
    public final class WebSecurity extends AbstractConfiguredSecurityBuilder<Filter, WebSecurity> implements SecurityBuilder<Filter>, ApplicationContextAware {
    

    ...省略部分代码

    <span class="hljs-comment">//调用该方法通过securityFilterChainBuilder.build()方法来创建securityFilter过滤器</span>
    <span class="hljs-comment">//并添加到securityFilterChains对象中,包装成FilterChainProxy 返回</span>
    <span class="hljs-function"><span class="hljs-keyword">protected</span> Filter <span class="hljs-title">performBuild</span><span class="hljs-params">()</span> <span class="hljs-keyword">throws</span> Exception </span>{
        Assert.state(!<span class="hljs-keyword">this</span>.securityFilterChainBuilders.isEmpty(), <span class="hljs-string">"At least one SecurityBuilder&lt;? extends SecurityFilterChain&gt; needs to be specified. Typically this done by adding a @Configuration that extends WebSecurityConfigurerAdapter. More advanced users can invoke "</span> + WebSecurity.class.getSimpleName() + <span class="hljs-string">".addSecurityFilterChainBuilder directly"</span>);
        <span class="hljs-keyword">int</span> chainSize = <span class="hljs-keyword">this</span>.ignoredRequests.size() + <span class="hljs-keyword">this</span>.securityFilterChainBuilders.size();
        List&lt;SecurityFilterChain&gt; securityFilterChains = <span class="hljs-keyword">new</span> ArrayList(chainSize);
        Iterator var3 = <span class="hljs-keyword">this</span>.ignoredRequests.iterator();
    
        <span class="hljs-keyword">while</span>(var3.hasNext()) {
            RequestMatcher ignoredRequest = (RequestMatcher)var3.next();
            securityFilterChains.add(<span class="hljs-keyword">new</span> DefaultSecurityFilterChain(ignoredRequest, <span class="hljs-keyword">new</span> Filter[<span class="hljs-number">0</span>]));
        }
    
        var3 = <span class="hljs-keyword">this</span>.securityFilterChainBuilders.iterator();
    
        <span class="hljs-keyword">while</span>(var3.hasNext()) {
            SecurityBuilder&lt;? extends SecurityFilterChain&gt; securityFilterChainBuilder = (SecurityBuilder)var3.next();
            securityFilterChains.add(securityFilterChainBuilder.build());
        }
    
        FilterChainProxy filterChainProxy = <span class="hljs-keyword">new</span> FilterChainProxy(securityFilterChains);
        <span class="hljs-keyword">if</span>(<span class="hljs-keyword">this</span>.httpFirewall != <span class="hljs-keyword">null</span>) {
            filterChainProxy.setFirewall(<span class="hljs-keyword">this</span>.httpFirewall);
        }
    
        filterChainProxy.afterPropertiesSet();
        Filter result = filterChainProxy;
        <span class="hljs-keyword">if</span>(<span class="hljs-keyword">this</span>.debugEnabled) {
            <span class="hljs-keyword">this</span>.logger.warn(<span class="hljs-string">"
    
    ********************************************************************
    **********        Security debugging is enabled.       *************
    **********    This may include sensitive information.  *************
    **********      Do not use in a production system!     *************
    ********************************************************************
    
    "</span>);
            result = <span class="hljs-keyword">new</span> DebugFilter(filterChainProxy);
        }
    
        <span class="hljs-keyword">this</span>.postBuildAction.run();
        <span class="hljs-keyword">return</span> (Filter)result;
    }
    

    }

     4、举例说明如何将一个Configurer转换为filter

    ExpressionUrlAuthorizationConfigurer的继承关系 
    ExpressionUrlAuthorizationConfigurer->AbstractInterceptUrlConfigurer->AbstractHttpConfigurer->SecurityConfigurerAdapter->SecurityConfigurer 
    对应的init方法在SecurityConfigurerAdapter类中,是个空实现,什么也没有做,configure方法在SecurityConfigurerAdapter类中也有一个空实现,在AbstractInterceptUrlConfigurer类中进行了重写 

    Abstractintercepturlconfigurer.java代码 

    @Override  
        public void configure(H http) throws Exception {  
            FilterInvocationSecurityMetadataSource metadataSource = createMetadataSource(http);  
            if (metadataSource == null) {  
                return;  
            }  
            FilterSecurityInterceptor securityInterceptor = createFilterSecurityInterceptor(  
                    http, metadataSource, http.getSharedObject(AuthenticationManager.class));  
            if (filterSecurityInterceptorOncePerRequest != null) {  
                securityInterceptor  
                        .setObserveOncePerRequest(filterSecurityInterceptorOncePerRequest);  
            }  
            securityInterceptor = postProcess(securityInterceptor);  
            http.addFilter(securityInterceptor);  
            http.setSharedObject(FilterSecurityInterceptor.class, securityInterceptor);  
        }  
    ...  
    private AccessDecisionManager createDefaultAccessDecisionManager(H http) {  
            AffirmativeBased result = new AffirmativeBased(getDecisionVoters(http));  
            return postProcess(result);  
        }  
    ...  
    private FilterSecurityInterceptor createFilterSecurityInterceptor(H http,  
                FilterInvocationSecurityMetadataSource metadataSource,  
                AuthenticationManager authenticationManager) throws Exception {  
            FilterSecurityInterceptor securityInterceptor = new FilterSecurityInterceptor();  
            securityInterceptor.setSecurityMetadataSource(metadataSource);  
            securityInterceptor.setAccessDecisionManager(getAccessDecisionManager(http));  
            securityInterceptor.setAuthenticationManager(authenticationManager);  
            securityInterceptor.afterPropertiesSet();  
            return securityInterceptor;  
        }  
    

    4.1、 在这个类的configure中创建了一个FilterSecurityInterceptor,并且也可以明确看到spring security默认给我们创建的AccessDecisionManager是AffirmativeBased。 

    4.2、.最后再看下HttpSecurity类执行build的最后一步 performBuild,这个方法就是在HttpSecurity中实现的 

    Httpsecurity.java代码 

    @Override  
        protected DefaultSecurityFilterChain performBuild() throws Exception {  
            Collections.sort(filters, comparator);  
            return new DefaultSecurityFilterChain(requestMatcher, filters);  
        }  


    可以看到,这个类只是把我们追加到HttpSecurity中的security进行了排序,用的排序类是FilterComparator,从而保证我们的filter按照正确的顺序执行。接着将filters构建成filterChian返回。在前面WebSecurity的performBuild方法中,这个返回值会被包装成FilterChainProxy,并作为WebSecurity的build方法的放回值。从而以springSecurityFilterChain这个名称注册到springContext中(在WebSecurityConfiguration中做的) 

    4.3.在WebSecurity的performBuild方法的最后一步还执行了一个postBuildAction.run,这个方法也是spring security给我们提供的一个hooks,可以在build完成后再做一些事情,比如我们在WebSecurityConfigurerAdapter类的init方法中我们利用这个hook在构建完成后将FilterSecurityInterceptor赋值给了webSecurity类的filterSecurityInterceptor属性

    三、用户登录的验证和授权过程

          1、用户一次完整的登录验证和授权,是一个请求经过 层层拦截器从而实现权限控制,整个web端配置为DelegatingFilterProxy(springSecurity的委托过滤其代理类 ),它并不实现真正的过滤,而是所有过滤器链的代理类,真正执行拦截处理的是由spring 容器管理的个个filter bean组成的filterChain.

    调用实际的FilterChainProxy 的doFilterInternal()方法 去获取所有的拦截器并进行过滤处理如下是DelegatingFilterProxy的doFilter()方法

    public void doFilter(ServletRequest request, ServletResponse response, FilterChain filterChain) throws ServletException, IOException {
            Filter delegateToUse = this.delegate;
            if(delegateToUse == null) {
                Object var5 = this.delegateMonitor;
                synchronized(this.delegateMonitor) {
                    delegateToUse = this.delegate;
                    if(delegateToUse == null) {
                        WebApplicationContext wac = this.findWebApplicationContext();
                        if(wac == null) {
                            throw new IllegalStateException("No WebApplicationContext found: no ContextLoaderListener or DispatcherServlet registered?");
                        }
    
                        delegateToUse = this.initDelegate(wac);
                    }
    
                    this.delegate = delegateToUse;
                }
            }
    
    //调用实际的FilterChainProxy 的doFilterInternal()方法 去获取所有的拦截器并进行过滤处理
            this.invokeDelegate(delegateToUse, request, response, filterChain);
        }
    

    调用实际的FilterChainProxy 的doFilter()方法 去获取所有的拦截器并进行过滤处理。

    2、FilterChainProxy类

        最终调用FilterChainProxy 的doFilterInternal()方法,获取所有的过滤器实例

    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
            boolean clearContext = request.getAttribute(FILTER_APPLIED) == null;
            if(clearContext) {
                try {
                    request.setAttribute(FILTER_APPLIED, Boolean.TRUE);
                    //doFilter 调用doFilterInternal方法
                    this.doFilterInternal(request, response, chain);
                } finally {
                    SecurityContextHolder.clearContext();
                    request.removeAttribute(FILTER_APPLIED);
                }
            } else {
                this.doFilterInternal(request, response, chain);
            }
    
        }
    
        private void doFilterInternal(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
            FirewalledRequest fwRequest = this.firewall.getFirewalledRequest((HttpServletRequest)request);
            HttpServletResponse fwResponse = this.firewall.getFirewalledResponse((HttpServletResponse)response);
             //过去所有的过滤器
            List<Filter> filters = this.getFilters((HttpServletRequest)fwRequest);
            if(filters != null && filters.size() != 0) {
                FilterChainProxy.VirtualFilterChain vfc = new FilterChainProxy.VirtualFilterChain(fwRequest, chain, filters);
                vfc.doFilter(fwRequest, fwResponse);
            } else {
                if(logger.isDebugEnabled()) {
                    logger.debug(UrlUtils.buildRequestUrl(fwRequest) + (filters == null?" has no matching filters":" has an empty filter list"));
                }
    
                fwRequest.reset();
                chain.doFilter(fwRequest, fwResponse);
            }
        }
    
    
      private List<Filter> getFilters(HttpServletRequest request) {
           //遍历所有的matcher类 如果支持就继续获取
            Iterator var2 = this.filterChains.iterator();
    
            SecurityFilterChain chain;
            do {
                if(!var2.hasNext()) {
                    return null;
                }
    
                chain = (SecurityFilterChain)var2.next();
            } while(!chain.matches(request));
            //后去匹配中的所有过滤器
            return chain.getFilters();
        }

    如上 其实是获取到本次请求的所有filter 并安装指定顺序进行执行doFilter()方法

    这是笔者本次业务请求所要执行的所有过滤器 

    1.     WebAsyncManagerIntegrationFilter
    2.      SecurityContextPersistenceFilter
    3.      HeaderWriterFilter     
    4.      LogoutFilter
    5.      UsernamePasswordAuthenticationFilter
    6.      RequestCacheAwareFilter
    7.      SecurityContextHolderAwareRequestFilter
    8.      AnonymousAuthenticationFilter
    9.      SessionManagementFilter
    10.      ExceptionTranslationFilter
    11.      FilterSecurityInterceptor

    关于springSecutity拦截器的介绍请参考如下链接地址

    https://blog.csdn.net/dushiwodecuo/article/details/78913113

    http://blog.didispace.com/xjf-spring-security-4/

    https://www.cnblogs.com/HHR-SUN/p/7095720.html

    https://blog.csdn.net/zheng963/article/details/50427320

    https://blog.csdn.net/m0_37834471/article/details/81142246

    https://www.cnblogs.com/mingluosunshan/p/5485259.html

    原文地址:https://blog.csdn.net/liushangzaibeijing/article/details/81220610
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  • 原文地址:https://www.cnblogs.com/jpfss/p/11022461.html
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