如何设置过滤器以处理并非所有请求？

Question

我正在使用 Spring Core、Spring MVC、Spring REST、JWT。

大家好！

我在学习 Spring Security，遇到了一个问题。

我想做一个基于 JWT 的认证；我有一个带有 3 个简单方法的 Rest 控制器：

第一种方法应该对所有人都可用，第二种方法仅适用于登录用户，第三种方法仅适用于管理员。虽然这样可行，但我还有另一个问题。

问题是我的过滤器每次启动后都会抛出（不是直接，因为 null 是由token = header.substring(7) 返回的）NullPointerException，即使它还没有收到任何请求（我可能是错的，我希望代码能澄清它）。是否可以设置过滤器以仅处理选定的请求，或者我的方法可能是错误的？

感谢您的帮助！

错误：

java.lang.NullPointerException
    at com.sample.config.JwtFilter.getAuthenticationByToken(JwtFilter.java:50)
    at com.sample.config.JwtFilter.doFilterInternal(JwtFilter.java:36)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
    at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:116)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
    at org.springframework.security.web.csrf.CsrfFilter.doFilterInternal(CsrfFilter.java:100)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
    at org.springframework.security.web.header.HeaderWriterFilter.doFilterInternal(HeaderWriterFilter.java:66)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
    at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:105)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
    at org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:56)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334)
    at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:215)
    at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:178)
    at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:357)
    at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:270)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:526)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:678)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:860)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1587)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.base/java.lang.Thread.run(Unknown Source)

我的JwtFilter：

public class JwtFilter extends BasicAuthenticationFilter {

    public JwtFilter(AuthenticationManager authenticationManager) {
        super(authenticationManager);

    }

    @Override   
    protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain chain)
            throws IOException, ServletException {
        String header=request.getHeader("authorization");
        UsernamePasswordAuthenticationToken authResult=getAuthenticationByToken(header);

        SecurityContextHolder.getContext().setAuthentication(authResult);

        chain.doFilter(request, response);
    }

    private UsernamePasswordAuthenticationToken getAuthenticationByToken(String header) {
            String token = header.substring(7);
            Jws<Claims> claims = Jwts.parser().setSigningKey("fQx]n}YmL)WuHjL".getBytes()).parseClaimsJws(token);

            String username=claims.getBody().get("name").toString();
            String role = claims.getBody().get("role").toString();
    return new UsernamePasswordAuthenticationToken(username,null,Collections.singleton(new SimpleGrantedAuthority(role)));      
    }

}

我的配置：

@Configuration
@EnableWebSecurity
public class SpringSecurityConfig extends WebSecurityConfigurerAdapter{

    @Override
    protected AuthenticationManager authenticationManager() throws Exception {
        return new AuthenticationManager() {

            @Override
            public Authentication authenticate(Authentication authentication) throws AuthenticationException {
                return null;
            }
        };
    }

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http.authorizeRequests().antMatchers("/api/test2").authenticated()      .antMatchers("/api/test3").hasRole("ADMIN")
        .and()
        .addFilter(new JwtFilter(authenticationManager())); }
}

public class SpringSecurityWebInitializer extends AbstractSecurityWebApplicationInitializer{

}

控制器：

@RestController
@RequestMapping("/api")
public class TestApi {

    @GetMapping("/test1")
    public String test1()
    {
        return "test1";//for everyone
    }

    @GetMapping("/test2")
    public String test2()
    {
        return "test2";//only for logged in
    }

    @GetMapping("/test3")
    public String test3()
    {
        return "test3";//only for admins 
    }   
}

Answer 1

按照您配置应用程序的方式，将为每个请求调用您的过滤器，因为安全性FilterChain“适用于”每个请求。

这一行：

http.authorizeRequests()
        .antMatchers("/api/test2").authenticated()      
        .antMatchers("/api/test3").hasRole("ADMIN")
        ...

... 不会阻止请求通过FilterChain。它只是允许匹配这些路径的请求通过过滤器而不经过身份验证。但是您注册的每个过滤器（例如JwtFilter）都会被调用。

解决方案

您可以通过覆盖WebSecurityConfigurerAdapter 中的configure(WebSecurity) 方法来为某些请求禁用整个FilterChain：

@Override
public void configure(WebSecurity web) {
    web.ignoring().mvcMatchers(...);
}

但在您的情况下，最好更改您的过滤器，以便它根据传入请求的路径跳过某些请求。您可以执行以下操作：

public class JwtFilter extends BasicAuthenticationFilter {
    private AntPathRequestMatcher filterPath;

    // the path you provide will restrict the filter to only be "applied"
    // to requests with that path
    public JwtFilter(AuthenticationManager authenticationManager, String path) {
        super(authenticationManager);
        this.filterPath = new AntPathRequestMatcher(path);
    }

    @Override   
    protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain chain)
            throws IOException, ServletException {

        // the filter will do nothing if the request doesn't match
        if(!filterPath.matches(request) {
            chain.doFilter(request, response);
        }

        // your filter logic goes here...

        chain.doFilter(request, response);
    }

    // ...
}