/**
 * 對已認(rèn)證用戶無權(quán)限的處理
 */
@Component
public class JsonAccessDeniedHandler implements AccessDeniedHandler {
    @Override
    public void handle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, AccessDeniedException e) throws IOException, ServletException {
        httpServletResponse.setCharacterEncoding("utf-8");
        httpServletResponse.setContentType("application/json;charset=utf-8");
		// 提示無權(quán)限        
        httpServletResponse.getWriter().print(JSONObject.toJSONString(new BaseResult<String>(NO_PERMISSION, false, null)));
    }
}

/**
 * 對匿名用戶無權(quán)限的處理
 */
@Component
public class JsonAuthenticationEntryPoint implements AuthenticationEntryPoint {
    @Override
    public void commence(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, AuthenticationException e) throws IOException, ServletException {
        httpServletResponse.setCharacterEncoding("utf-8");
        httpServletResponse.setContentType("application/json;charset=utf-8");
		// 認(rèn)證失敗        
        httpServletResponse.getWriter().print(JSONObject.toJSONString(new BaseResult<String>(e.getMessage(), false, null)));
    }
}

/**
 * @Author chongyahhh
 * 驗證碼登錄配置
 */
@Component
@RequiredArgsConstructor(onConstructor = @__(@Autowired))
public class VerificationLoginConfig extends SecurityConfigurerAdapter<DefaultSecurityFilterChain, HttpSecurity> {
    private final VerificationAuthenticationProvider verificationAuthenticationProvider;
    @Qualifier("tokenAuthenticationDetailsSource")
    private AuthenticationDetailsSource<HttpServletRequest, WebAuthenticationDetails> authenticationDetailsSource;
    @Override
    public void configure(HttpSecurity http) throws Exception {
        VerificationAuthenticationFilter verificationAuthenticationFilter = new VerificationAuthenticationFilter();
        verificationAuthenticationFilter.setAuthenticationManager(http.getSharedObject((AuthenticationManager.class)));
        http
                .authenticationProvider(verificationAuthenticationProvider)
                .addFilterAfter(verificationAuthenticationFilter, UsernamePasswordAuthenticationFilter.class); // 將VerificationAuthenticationFilter加到UsernamePasswordAuthenticationFilter后面
    }
}

/**
 * @Author chongyahhh
 * Spring Security 配置
 */
@Configuration
@EnableWebSecurity
@EnableGlobalMethodSecurity(prePostEnabled = true)
@RequiredArgsConstructor(onConstructor = @__(@Autowired))
public class SecurityConfig extends WebSecurityConfigurerAdapter {
    private final AuthenticationEntryPoint jsonAuthenticationEntryPoint;
    private final AccessDeniedHandler jsonAccessDeniedHandler;
    private final VerificationLoginConfig verificationLoginConfig;
    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http
                    .apply(verificationLoginConfig) // 用戶名密碼驗證碼登錄配置導(dǎo)入
                .and()
                    .exceptionHandling()
                    .authenticationEntryPoint(jsonAuthenticationEntryPoint) // 注冊自定義認(rèn)證異常入口
                    .accessDeniedHandler(jsonAccessDeniedHandler) // 注冊自定義授權(quán)異常入口
                .and()
                    .anonymous()
                .and()
                    .formLogin()
                .and()
                    .csrf().disable(); // 關(guān)閉 csrf，防止首次的 POST 請求被攔截
    }
    @Bean("customSecurityExpressionHandler")
    public DefaultWebSecurityExpressionHandler webSecurityExpressionHandler(){
        DefaultWebSecurityExpressionHandler handler = new DefaultWebSecurityExpressionHandler();
        handler.setPermissionEvaluator(new CustomPermissionEvaluator());
        return handler;
    }
}

/**
 * @Author chongyahhh
 * 驗證碼登錄過濾器
 */
public class VerificationAuthenticationFilter extends AbstractAuthenticationProcessingFilter {
    private static final String USERNAME = "username";
    private static final String PASSWORD = "password";
    private static final String VERIFICATION_CODE = "verificationCode";
    private boolean postOnly = true;
    public VerificationAuthenticationFilter() {
        super(new AntPathRequestMatcher(SECURITY_VERIFICATION_CODE_LOGIN, "POST"));
        // 繼續(xù)執(zhí)行攔截器鏈，執(zhí)行被攔截的 url 對應(yīng)的接口
        super.setContinueChainBeforeSuccessfulAuthentication(true);
    }
    @Override
    public Authentication attemptAuthentication(HttpServletRequest request, HttpServletResponse response) throws AuthenticationException, IOException, ServletException {
        if (this.postOnly && !request.getMethod().equals("POST")) {
            throw new AuthenticationServiceException("Authentication method not supported: " + request.getMethod());
        }
        String verificationCode = this.obtainVerificationCode(request);
        System.out.println("驗證中...");
        String username = this.obtainUsername(request);
        String password = this.obtainPassword(request);
        username = (username == null) ? "" : username;
        password = (password == null) ? "" : password;
        username = username.trim();
        VerificationAuthenticationToken authRequest = new VerificationAuthenticationToken(username, password);
        //this.setDetails(request, authRequest);
        return this.getAuthenticationManager().authenticate(authRequest);
    }
    private String obtainPassword(HttpServletRequest request) {
        return request.getParameter(PASSWORD);
    }
    private String obtainUsername(HttpServletRequest request) {
        return request.getParameter(USERNAME);
    }
    private String obtainVerificationCode(HttpServletRequest request) {
        return request.getParameter(VERIFICATION_CODE);
    }
    private void setDetails(HttpServletRequest request, VerificationAuthenticationToken authRequest) {
        authRequest.setDetails(this.authenticationDetailsSource.buildDetails(request));
    }
    private boolean validate(String verificationCode) {
        HttpServletRequest request = ((ServletRequestAttributes) RequestContextHolder.getRequestAttributes()).getRequest();
        HttpSession session = request.getSession();
        Object validateCode = session.getAttribute(VERIFICATION_CODE);
        if(validateCode == null) {
            return false;
        }
        // 不分區(qū)大小寫
        return StringUtils.equalsIgnoreCase((String)validateCode, verificationCode);
    }
}

private void handleSpringSecurityException(HttpServletRequest request,
			HttpServletResponse response, FilterChain chain, RuntimeException exception)
			throws IOException, ServletException {
		if (exception instanceof AuthenticationException) { // 認(rèn)證異常
			...
			sendStartAuthentication(request, response, chain,
					(AuthenticationException) exception); // 在這里調(diào)用 AuthenticationEntryPoint 的 commence 方法
		} else if (exception instanceof AccessDeniedException) { // 無權(quán)限
			Authentication authentication = SecurityContextHolder.getContext().getAuthentication();
			if (authenticationTrustResolver.isAnonymous(authentication) || authenticationTrustResolver.isRememberMe(authentication)) {
				...
				sendStartAuthentication(
						request,
						response,
						chain,
						new InsufficientAuthenticationException(
							messages.getMessage(
								"ExceptionTranslationFilter.insufficientAuthentication",
								"Full authentication is required to access this resource"))); // 在這里調(diào)用 AuthenticationEntryPoint 的 commence 方法
			} else {
				...
				accessDeniedHandler.handle(request, response,
						(AccessDeniedException) exception); // 在這里調(diào)用 AccessDeniedHandler 的 handle 方法
			}
		}
	}

public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain)
			throws IOException, ServletException {
		HttpServletRequest request = (HttpServletRequest) req;
		HttpServletResponse response = (HttpServletResponse) res;
		try {
			chain.doFilter(request, response);
			logger.debug("Chain processed normally");
		}
		catch (IOException ex) {
			throw ex;
		}
		catch (Exception ex) {
			// Try to extract a SpringSecurityException from the stacktrace
			Throwable[] causeChain = throwableAnalyzer.determineCauseChain(ex);
			RuntimeException ase = (AuthenticationException) throwableAnalyzer
					.getFirstThrowableOfType(AuthenticationException.class, causeChain);
			if (ase == null) {
				ase = (AccessDeniedException) throwableAnalyzer.getFirstThrowableOfType(
						AccessDeniedException.class, causeChain);
			}
			if (ase != null) {
				if (response.isCommitted()) {
					throw new ServletException("Unable to handle the Spring Security Exception because the response is already committed.", ex);
				}
				// 這里進(jìn)入上面的方法?。?！
				handleSpringSecurityException(request, response, chain, ase);
			}
			else {
				// Rethrow ServletExceptions and RuntimeExceptions as-is
				if (ex instanceof ServletException) {
					throw (ServletException) ex;
				}
				else if (ex instanceof RuntimeException) {
					throw (RuntimeException) ex;
				}
				// Wrap other Exceptions. This shouldn't actually happen
				// as we've already covered all the possibilities for doFilter
				throw new RuntimeException(ex);
			}
		}
	}

public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain)
			throws IOException, ServletException {
		HttpServletRequest request = (HttpServletRequest) req;
		HttpServletResponse response = (HttpServletResponse) res;
     	// 在此處進(jìn)行 url 匹配，如果不是該攔截器攔截的 url，就直接執(zhí)行下一個攔截器的攔截
		if (!requiresAuthentication(request, response)) {
			chain.doFilter(request, response);
			return;
		}
		if (logger.isDebugEnabled()) {
			logger.debug("Request is to process authentication");
		}
		Authentication authResult;
		try {
			// 調(diào)用我們實現(xiàn)的 VerificationAuthenticationFilter 中的 attemptAuthentication 方法，進(jìn)行登錄邏輯驗證
			authResult = attemptAuthentication(request, response);
			if (authResult == null) {
				return;
			}
			sessionStrategy.onAuthentication(authResult, request, response);
		} catch (InternalAuthenticationServiceException failed) {
			logger.error(
					"An internal error occurred while trying to authenticate the user.",
					failed);
			unsuccessfulAuthentication(request, response, failed);
			return;
		} catch (AuthenticationException failed) {
			//
			// 注意這里，如果登錄失敗，我們拋出的異常會在這里被抓取，然后通過 unsuccessfulAuthentication 進(jìn)行處理
			// 翻閱 unsuccessfulAuthentication 中的代碼我們可以發(fā)現(xiàn)，如果我們沒有設(shè)置認(rèn)證失敗后的重定向url，就會封裝一個401的響應(yīng)，也就是我們上面出現(xiàn)的情況
			// 
			unsuccessfulAuthentication(request, response, failed);
			// 執(zhí)行完成后直接中斷攔截器鏈的執(zhí)行
			return;
		}
		// 如果登錄成功就繼續(xù)執(zhí)行，我們設(shè)置的 continueChainBeforeSuccessfulAuthentication 為 true
		if (continueChainBeforeSuccessfulAuthentication) {
			chain.doFilter(request, response);
		}
		successfulAuthentication(request, response, chain, authResult);
	}

public class JsonAuthenticationFailureHandler implements AuthenticationFailureHandler {
    @Override
    public void onAuthenticationFailure(HttpServletRequest request, HttpServletResponse response, AuthenticationException exception) throws IOException, ServletException {
        response.setCharacterEncoding("utf-8");
        response.setContentType("application/json;charset=utf-8");
        response.getWriter().print(JSONObject.toJSONString(new BaseResult<String>(exception.getMessage(), false, null)));
    }
}

public class VerificationAuthenticationFilter extends AbstractAuthenticationProcessingFilter {
    private static final String USERNAME = "username";
    private static final String PASSWORD = "password";
    private static final String VERIFICATION_CODE = "verificationCode";
    private boolean postOnly = true;
    public VerificationAuthenticationFilter() {
        super(new AntPathRequestMatcher(SECURITY_VERIFICATION_CODE_LOGIN, "POST"));
        // 繼續(xù)執(zhí)行攔截器鏈，執(zhí)行被攔截的 url 對應(yīng)的接口
        super.setContinueChainBeforeSuccessfulAuthentication(true);
        // 設(shè)置認(rèn)證失敗處理入口
        setAuthenticationFailureHandler(new JsonAuthenticationFailureHandler());
    }
    ...
}