SSO - CAS：不拦截指定url过滤

首先我们看一下我们客户端中web.xml中的拦截器配置

    <filter>
        <filter-name>CASFilterfilter-name>
        <filter-class>org.jasig.cas.client.authentication.AuthenticationFilterfilter-class>
        <init-param>
            <param-name>casServerLoginUrlparam-name>
            <param-value>http://ssocas.ane56.com:8080/cas/loginparam-value>
        init-param>
        <init-param>
            <param-name>serverNameparam-name>
            <param-value>http://ptl.ane56.com:8080param-value>
        init-param>
    filter>
    <filter-mapping>
        <filter-name>CASFilterfilter-name>
        <url-pattern>/*url-pattern>
    filter-mapping>

重要的操作无非就是客户端jar包中的AuthenticationFilter，然后上网查了下，无非就是将这个拦截方法重写。

反编译一下

然后将该拦截器贴一下

package org.jasig.cas.client.authentication;

import java.io.IOException;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import org.apache.commons.logging.Log;
import org.jasig.cas.client.util.AbstractCasFilter;
import org.jasig.cas.client.util.CommonUtils;
import org.jasig.cas.client.validation.Assertion;

public class AuthenticationFilter extends AbstractCasFilter
{
  private String casServerLoginUrl;
  private boolean renew = false;

  private boolean gateway = false;

  private GatewayResolver gatewayStorage = new DefaultGatewayResolverImpl();

  protected void initInternal(FilterConfig filterConfig) throws ServletException {
    if (!isIgnoreInitConfiguration()) {
      super.initInternal(filterConfig);
      setCasServerLoginUrl(getPropertyFromInitParams(filterConfig, "casServerLoginUrl", null));
      this.log.trace("Loaded CasServerLoginUrl parameter: " + this.casServerLoginUrl);
      setRenew(parseBoolean(getPropertyFromInitParams(filterConfig, "renew", "false")));
      this.log.trace("Loaded renew parameter: " + this.renew);
      setGateway(parseBoolean(getPropertyFromInitParams(filterConfig, "gateway", "false")));
      this.log.trace("Loaded gateway parameter: " + this.gateway);

      String gatewayStorageClass = getPropertyFromInitParams(filterConfig, "gatewayStorageClass", null);

      if (gatewayStorageClass != null)
        try {
          this.gatewayStorage = ((GatewayResolver)Class.forName(gatewayStorageClass).newInstance());
        } catch (Exception e) {
          this.log.error(e, e);
          throw new ServletException(e);
        }
    }
  }

  public void init()
  {
    super.init();
    CommonUtils.assertNotNull(this.casServerLoginUrl, "casServerLoginUrl cannot be null.");
  }

  public final void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
    HttpServletRequest request = (HttpServletRequest)servletRequest;
    HttpServletResponse response = (HttpServletResponse)servletResponse;
    HttpSession session = request.getSession(false);
    Assertion assertion = session != null ? (Assertion)session.getAttribute("_const_cas_assertion_") : null;

    if (assertion != null) {
      filterChain.doFilter(request, response);
      return;
    }

    String serviceUrl = constructServiceUrl(request, response);
    String ticket = CommonUtils.safeGetParameter(request, getArtifactParameterName());
    boolean wasGatewayed = this.gatewayStorage.hasGatewayedAlready(request, serviceUrl);

    if ((CommonUtils.isNotBlank(ticket)) || (wasGatewayed)) {
      filterChain.doFilter(request, response);
      return;
    }

    this.log.debug("no ticket and no assertion found");
    String modifiedServiceUrl;
    String modifiedServiceUrl;
    if (this.gateway) {
      this.log.debug("setting gateway attribute in session");
      modifiedServiceUrl = this.gatewayStorage.storeGatewayInformation(request, serviceUrl);
    } else {
      modifiedServiceUrl = serviceUrl;
    }

    if (this.log.isDebugEnabled()) {
      this.log.debug("Constructed service url: " + modifiedServiceUrl);
    }

    String urlToRedirectTo = CommonUtils.constructRedirectUrl(this.casServerLoginUrl, getServiceParameterName(), modifiedServiceUrl, this.renew, this.gateway);

    if (this.log.isDebugEnabled()) {
      this.log.debug("redirecting to \"" + urlToRedirectTo + "\"");
    }

    response.sendRedirect(urlToRedirectTo);
  }

  public final void setRenew(boolean renew) {
    this.renew = renew;
  }

  public final void setGateway(boolean gateway) {
    this.gateway = gateway;
  }

  public final void setCasServerLoginUrl(String casServerLoginUrl) {
    this.casServerLoginUrl = casServerLoginUrl;
  }

  public final void setGatewayStorage(GatewayResolver gatewayStorage) {
    this.gatewayStorage = gatewayStorage;
  }
}

   我们重新定义一个类ReAuthenticationFilter，也继承AbstractCasFilter类，在该类中完全复制AuthenticationFilter类中的内容，并在我们自己的拦截器做如下修改：

 1.增加excepPaths属性，用于存放要排除过滤的路径，采用数组方式存放，应对多个url头的拦截。

private String[] excludePaths;

 2.修改initInternal方法、从web.xml配置中解析出要排除过滤的路径

 protected void initInternal(final FilterConfig filterConfig) throws ServletException {
        if (!isIgnoreInitConfiguration()) {
            super.initInternal(filterConfig);
            setCasServerLoginUrl(getPropertyFromInitParams(filterConfig, "casServerLoginUrl", null));
            log.trace("Loaded CasServerLoginUrl parameter: " + this.casServerLoginUrl);
            setRenew(parseBoolean(getPropertyFromInitParams(filterConfig, "renew", "false")));
            log.trace("Loaded renew parameter: " + this.renew);
            setGateway(parseBoolean(getPropertyFromInitParams(filterConfig, "gateway", "false")));
            log.trace("Loaded gateway parameter: " + this.gateway);
            final String gatewayStorageClass = getPropertyFromInitParams(filterConfig, "gatewayStorageClass", null);
            if (gatewayStorageClass != null) {
                try {
                    this.gatewayStorage = (GatewayResolver) Class.forName(gatewayStorageClass).newInstance();
                } catch (final Exception e) {
                    log.error(e,e);
                    throw new ServletException(e);
                }
            }


            //拦截器过滤修改************begin*************************
            String _excludePaths = getPropertyFromInitParams(filterConfig, "excepPaths", null);
            if(CommonUtils.isNotBlank(_excludePaths)){
             setExcludePaths(_excludePaths.trim().split(","));
            }
            //拦截器过滤修改************end************************
        }
    }

 3.修改doFilter方法、判断请求路径是否需要过滤

    public final void doFilter(final ServletRequest servletRequest, final ServletResponse servletResponse, final FilterChain filterChain) throws IOException, ServletException {
        final HttpServletRequest request = (HttpServletRequest) servletRequest;
        final HttpServletResponse response = (HttpServletResponse) servletResponse;
        final HttpSession session = request.getSession(false);
        final Assertion assertion = session != null ? (Assertion) session.getAttribute(CONST_CAS_ASSERTION) : null;


        //拦截器过滤修改************begin********************
        boolean isAir = request.getParameter("isAir")!=null && "true".equals(request.getParameter("isAir"));
        if (isAir ) {
            filterChain.doFilter(request, response);
        }

        String uri = request.getRequestURI()+request.getQueryString;
        boolean isInWhiteList = false;
        if(excludePaths!=null && excludePaths.length>0 && uri!=null){
            for(String path : excludePaths){
             if(CommonUtils.isNotBlank(path)){
              isInWhiteList = uri.indexOf(path.trim())>-1;
               if(isInWhiteList){
                 break;
               }
              }
            }
        }
        
        if(isInWhiteList){
            filterChain.doFilter(request, response);
            return;
           }
        //拦截器过滤修改************end********************************
        
        if (assertion != null) {
            filterChain.doFilter(request, response);
            return;
        }
        final String serviceUrl = constructServiceUrl(request, response);
        final String ticket = CommonUtils.safeGetParameter(request,getArtifactParameterName());
        final boolean wasGatewayed = this.gatewayStorage.hasGatewayedAlready(request, serviceUrl);
        if (CommonUtils.isNotBlank(ticket) || wasGatewayed) {
            filterChain.doFilter(request, response);
            return;
        }
        final String modifiedServiceUrl;
        log.debug("no ticket and no assertion found");
        if (this.gateway) {
            log.debug("setting gateway attribute in session");
            modifiedServiceUrl = this.gatewayStorage.storeGatewayInformation(request, serviceUrl);
        } else {
            modifiedServiceUrl = serviceUrl;
        }
        if (log.isDebugEnabled()) {
            log.debug("Constructed service url: " + modifiedServiceUrl);
        }
        final String urlToRedirectTo = CommonUtils.constructRedirectUrl(this.casServerLoginUrl, getServiceParameterName(), modifiedServiceUrl, this.renew, this.gateway);
        if (log.isDebugEnabled()) {
            log.debug("redirecting to \"" + urlToRedirectTo + "\"");
        }
        response.sendRedirect(urlToRedirectTo);
    }

   4.修改完以上方法、则web.xml中还需要修改两点，修改后的web.xml配置如下：

    <filter>
        <filter-name>CASFilterfilter-name>
        <filter-class>org.jasig.cas.client.authentication.ReAuthenticationFilterfilter-class>
        <init-param>
            <param-name>casServerLoginUrlparam-name>
            <param-value>http://ssocas.ane56.com:8080/cas/loginparam-value>
        init-param>
        <init-param>
            <param-name>serverNameparam-name>
            <param-value>http://ptl.ane56.com:8080param-value>
        init-param>
        <init-param>
           <description>cas not filter urldescription>
           <param-name>exceptPathsparam-name>
           <param-value>isAir=true,/user/loginparam-value>
        init-param>
    filter>

惯例图示

ps:关于request取url参考：     http://zjutsoft.iteye.com/blog/1084260

从request获取各种路径总结 
request.getRealPath("url"); // 虚拟目录映射为实际目录

request.getRealPath("./");    // 网页所在的目录

request.getRealPath("../"); // 网页所在目录的上一层目录

request.getContextPath();    // 应用的web目录的名称

如http://localhost:7001/bookStore/ 
/bookStore/ => [contextPath] (request.getContextPath())

获取Web项目的全路径 
String strDirPath = request.getSession().getServletContext().getRealPath("/");

以工程名为TEST为例：

(1)得到包含工程名的当前页面全路径：request.getRequestURI() 
结果：/TEST/test.jsp

(2)得到工程名：request.getContextPath() 
结果：/TEST

(3)得到当前页面所在目录下全名称：request.getServletPath() 
结果：如果页面在jsp目录下 /TEST/jsp/test.jsp

(4)得到页面所在服务器的全路径：application.getRealPath("页面.jsp") 
结果：D:\resin\webapps\TEST\test.jsp

(5)得到页面所在服务器的绝对路径：absPath=new java.io.File(application.getRealPath(request.getRequestURI())).getParent(); 
结果：D:\resin\webapps\TEST

2.在类中取得路径：

(1)类的绝对路径：Class.class.getClass().getResource("/").getPath() 
结果：/D:/TEST/WebRoot/WEB-INF/classes/pack/

(2)得到工程的路径：System.getProperty("user.dir") 
结果：D:\TEST

3.在Servlet中取得路径：

(1)得到工程目录：request.getSession().getServletContext().getRealPath("") 参数可具体到包名。 
结果：E:\Tomcat\webapps\TEST

(2)得到IE地址栏地址：request.getRequestURL() 
结果：http://localhost:8080/TEST/test

(3)得到相对地址：request.getRequestURI() 
结果：/TEST/test

 

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以上CAS的配置是写在Web.xml中，也有很多不方便，配置应该统一到一处管理，用兴趣的小伙伴可以参考博主这篇文章哦

https://blog.csdn.net/qq_36698956/article/details/80979177

以上配置博主亲自操刀过，小伙伴如果出现什么问题可以给我留言哦，我会回复你的o(*￣︶￣*)o

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