Spring Security解析二：自动化装配

在spring-boot-autoconfigure-2.2.1/META-INF/spring.factories中有以下配置：

# Auto Configure
org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
org.springframework.boot.autoconfigure.security.servlet.SecurityAutoConfiguration,\
org.springframework.boot.autoconfigure.security.servlet.UserDetailsServiceAutoConfiguration,\
org.springframework.boot.autoconfigure.security.servlet.SecurityFilterAutoConfiguration,\
org.springframework.boot.autoconfigure.security.reactive.ReactiveSecurityAutoConfiguration,\
org.springframework.boot.autoconfigure.security.reactive.ReactiveUserDetailsServiceAutoConfiguration,\
org.springframework.boot.autoconfigure.security.rsocket.RSocketSecurityAutoConfiguration,\
org.springframework.boot.autoconfigure.security.saml2.Saml2RelyingPartyAutoConfiguration

1，SecurityAutoConfiguration

@Configuration(proxyBeanMethods = false)
@ConditionalOnClass(DefaultAuthenticationEventPublisher.class)
//读取配置信息
@EnableConfigurationProperties(SecurityProperties.class)
//导入其他配置
@Import({ SpringBootWebSecurityConfiguration.class, WebSecurityEnablerConfiguration.class,
        SecurityDataConfiguration.class })
public class SecurityAutoConfiguration {

    @Bean
    @ConditionalOnMissingBean(AuthenticationEventPublisher.class)
    public DefaultAuthenticationEventPublisher authenticationEventPublisher(ApplicationEventPublisher publisher) {
        return new DefaultAuthenticationEventPublisher(publisher);
    }
}

1.1 SpringBootWebSecurityConfiguration

@Configuration(proxyBeanMethods = false)
@ConditionalOnClass(WebSecurityConfigurerAdapter.class)
@ConditionalOnMissingBean(WebSecurityConfigurerAdapter.class)
@ConditionalOnWebApplication(type = Type.SERVLET)
public class SpringBootWebSecurityConfiguration {

    @Configuration(proxyBeanMethods = false)
    @Order(SecurityProperties.BASIC_AUTH_ORDER)
    static class DefaultConfigurerAdapter extends WebSecurityConfigurerAdapter {
    }
}

1.2 WebSecurityEnablerConfiguration

此配置类只为了启动使用@EnableWebSecurity来启动安全框架

@Configuration(proxyBeanMethods = false)
@ConditionalOnBean(WebSecurityConfigurerAdapter.class)
@ConditionalOnMissingBean(name = BeanIds.SPRING_SECURITY_FILTER_CHAIN)
@ConditionalOnWebApplication(type = ConditionalOnWebApplication.Type.SERVLET)
//此处添加了WebSecurity的启动注解，所以Springboot中是不需要显示添加的
@EnableWebSecurity
public class WebSecurityEnablerConfiguration {
}

1.3 SecurityDataConfiguration

该配置为了添加与Spring Data集成的支持

/**
 * Automatically adds Spring Security's integration with Spring Data.
 *
 * @author Rob Winch
 * @since 1.3.0
 */
@Configuration(proxyBeanMethods = false)
@ConditionalOnClass(SecurityEvaluationContextExtension.class)
public class SecurityDataConfiguration {
    @Bean
    @ConditionalOnMissingBean
    public SecurityEvaluationContextExtension securityEvaluationContextExtension() {
        return new SecurityEvaluationContextExtension();
    }
}

2，SecurityFilterAutoConfiguration

在SecurityAutoConfiguration配置来后执行，该处是Security过滤器自动添加到ServletContext上的关键

@Configuration(proxyBeanMethods = false)
@ConditionalOnWebApplication(type = Type.SERVLET)
@EnableConfigurationProperties(SecurityProperties.class)
@ConditionalOnClass({ AbstractSecurityWebApplicationInitializer.class, SessionCreationPolicy.class })
@AutoConfigureAfter(SecurityAutoConfiguration.class)
public class SecurityFilterAutoConfiguration {

    private static final String DEFAULT_FILTER_NAME = AbstractSecurityWebApplicationInitializer.DEFAULT_FILTER_NAME;


    //通过创建springSecurityFilterChain的委托DelegatingFilterProxyRegistrationBean
    //便能在Tomcat启动过程中注册到ServletContext下
    @Bean
    @ConditionalOnBean(name = DEFAULT_FILTER_NAME)
    public DelegatingFilterProxyRegistrationBean securityFilterChainRegistration(
            SecurityProperties securityProperties) {
        //设置所委托Filter对应的Bean名（“解析一”里面创建的Filter）
        DelegatingFilterProxyRegistrationBean registration = new DelegatingFilterProxyRegistrationBean(
                DEFAULT_FILTER_NAME);
        //默认的order为： -100
        registration.setOrder(securityProperties.getFilter().getOrder());
        registration.setDispatcherTypes(getDispatcherTypes(securityProperties));
        return registration;
    }

    private EnumSet<DispatcherType> getDispatcherTypes(SecurityProperties securityProperties) {
        if (securityProperties.getFilter().getDispatcherTypes() == null) {
            return null;
        }
        return securityProperties.getFilter().getDispatcherTypes().stream()
                .map((type) -> DispatcherType.valueOf(type.name()))
                .collect(Collectors.collectingAndThen(Collectors.toSet(), EnumSet::copyOf));
    }
}

3，UserDetailsServiceAutoConfiguration

为Spring Security配置默认的基于内存的认证管理器

@Configuration(proxyBeanMethods = false)
@ConditionalOnClass(AuthenticationManager.class)
@ConditionalOnBean(ObjectPostProcessor.class)
@ConditionalOnMissingBean(
        value = { AuthenticationManager.class, AuthenticationProvider.class, UserDetailsService.class },
        type = { "org.springframework.security.oauth2.jwt.JwtDecoder",
                "org.springframework.security.oauth2.server.resource.introspection.OpaqueTokenIntrospector" })
public class UserDetailsServiceAutoConfiguration {

    private static final String NOOP_PASSWORD_PREFIX = "{noop}";

    private static final Pattern PASSWORD_ALGORITHM_PATTERN = Pattern.compile("^\\{.+}.*$");

    private static final Log logger = LogFactory.getLog(UserDetailsServiceAutoConfiguration.class);

    @Bean
    @ConditionalOnMissingBean(
            type = "org.springframework.security.oauth2.client.registration.ClientRegistrationRepository")
    @Lazy
    public InMemoryUserDetailsManager inMemoryUserDetailsManager(SecurityProperties properties,
            ObjectProvider<PasswordEncoder> passwordEncoder) {
        //配置的用户名信息，看下面User的定义
        SecurityProperties.User user = properties.getUser();
        List<String> roles = user.getRoles();
        return new InMemoryUserDetailsManager(
                User.withUsername(user.getName()).password(getOrDeducePassword(user, passwordEncoder.getIfAvailable()))
                        .roles(StringUtils.toStringArray(roles)).build());
    }

    private String getOrDeducePassword(SecurityProperties.User user, PasswordEncoder encoder) {
        String password = user.getPassword();
        if (user.isPasswordGenerated()) {
            logger.info(String.format("%n%nUsing generated security password: %s%n", user.getPassword()));
        }
        if (encoder != null || PASSWORD_ALGORITHM_PATTERN.matcher(password).matches()) {
            return password;
        }
        return NOOP_PASSWORD_PREFIX + password;
    }

}

3.1 SecurityProperties.User

@ConfigurationProperties(prefix = "spring.security")
public class SecurityProperties {
    private User user = new User();
    public User getUser() {
        return this.user;
    }

    public static class User {
        /**
         * Default user name.
         */
        private String name = "user";

        /**
         * Password for the default user name.
         */
        private String password = UUID.randomUUID().toString();

        /**
         * Granted roles for the default user name.
         */
        private List<String> roles = new ArrayList<>();

        ... ... 
    }
}

可见默认的用户名为“user”，密码为随机生成。

小结：

基于spring-boot-autoconfigure-2.2.1/META-INF/spring.factories中对Security的自动化配置完成了Security的启动，同时完成了Filter的装配工作，最后还提供了基于内存的默认的用户登录验证数据。