SpringSecurity源码学习

﹏ヽ暗。殇╰゛Y 2022-09-03 13:11 244阅读 0赞

## SpringSecurity源码学习 ##

![image-20210620180117785][]

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#### 一、Spring-Boot的自动配置 ####

看到它的自动配置类：`SecurityFilterAutoConfiguration`

@Bean
    	@ConditionalOnBean(name = DEFAULT_FILTER_NAME)
    	public DelegatingFilterProxyRegistrationBean securityFilterChainRegistration(
    			SecurityProperties securityProperties) { 
    		DelegatingFilterProxyRegistrationBean registration = new DelegatingFilterProxyRegistrationBean(
    				DEFAULT_FILTER_NAME);
    		registration.setOrder(securityProperties.getFilter().getOrder());
    		registration.setDispatcherTypes(getDispatcherTypes(securityProperties));
    		return registration;
    	}

该自动配置类中向容器加入了DelegatingFilterProxyRegistrationBean注册器，并传入了一个目标bean名称springSecurityFilterChain，其实SpringSecurity的内部核心就是一系列过滤器链；它是基于责任链的设计模式，

#### 二、SpringSecurity基本流程 ####

![image-20210606163557677][]

##### 2.1 **UsernamePasswordAuthenticationFilter** #####

该过滤器主要是拦截前端提交的POST请求，进行认证处理，代码如下：

// 在父类中
    public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain)
    			throws IOException, ServletException { 
    
    		HttpServletRequest request = (HttpServletRequest) req;
    		HttpServletResponse response = (HttpServletResponse) res;
    	  
      
      // 判断是登录请求，这里也就是我们在配置类中设置的登录url
      // 并且判断是否为post请求
    		if (!requiresAuthentication(request, response)) { 
    			chain.doFilter(request, response);
    
    			return;
    		}
    
    		if (logger.isDebugEnabled()) { 
    			logger.debug("Request is to process authentication");
    		}
    		// 这个是用来存储用户认证信息的类
    		Authentication authResult;
    
    		try { 
          // 获取认证信息；会调用UsernamePasswordAuthenticationFilter的attemptAuthentication
          // 获取到表单数据
    			authResult = attemptAuthentication(request, response);

attemptAuthentication(request, response)方法

HttpServletResponse response) throws AuthenticationException { 
    		if (postOnly && !request.getMethod().equals("POST")) { 
    			throw new AuthenticationServiceException(
    					"Authentication method not supported: " + request.getMethod());
    		}
    		// 获取到用户名&密码
    		String username = obtainUsername(request);
    		String password = obtainPassword(request);
    
    		if (username == null) { 
    			username = "";
    		}
    
    		if (password == null) { 
    			password = "";
    		}
    
    		username = username.trim();
    		
          // 构造UsernamePasswordAuthenticationToken内部能够存储认证前和认证后到信息
    		UsernamePasswordAuthenticationToken authRequest = new UsernamePasswordAuthenticationToken(
    				username, password);
    
    		// Allow subclasses to set the "details" property
    		setDetails(request, authRequest);
    		
        // Manager的认证方法
    		return this.getAuthenticationManager().authenticate(authRequest);

##### ProviderManager #####

这个是认证的入口，这个内部会维护多种认证方式，是一个List 认证时实际上是委托模式，找到对应的认证，根据传入的Authentication;

// ProviderManager内部代码，我们用的表单认证，这个类是UsernamePasswordAuthenticationToken.class
    for (AuthenticationProvider provider : getProviders()) { 
    			// 判断是否匹配
      if (!provider.supports(toTest)) { 
    				continue;
    			}
      // 获取认证结果，会调用到UserDetailsService的认证方法，返回用户信息
      // 否则会认证失败
      result = provider.authenticate(authentication);

与之匹配的认证器是DaoAuthenticationProvider，**内部关联了UserDetailsService，这样就会进行自定义的认证方式，也就是查询数据库。**

#### 参考文献：https://docs.spring.io/spring-security/site/docs/5.4.5/reference/html5/\#servlet-hello ####

[image-20210620180117785]: /images/20220829/a2718e097bba488dbca886b02cfbd893.png
[image-20210620200309838]: /images/20220829/32fd7dd4f83e4ab78a630217a6b4e403.png
[image-20210606163557677]: /images/20220829/97f42f5b125c4d7f9265e641755edbdd.png