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Cas自定义登录页面Ajax实现

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• SSO

Casajax自定义页面 

本文是基于CAS 之自定义登录页实践及CAS 之 跨域 Ajax 登录实践而实现的,主要是针对最新的Cas实现自定义登录页的Ajax跨域实现. 

环境： 
        cas-server-3.5.1-release 
        cas地址:  http://localhost:8080/cas/ 
        client地址:  http://localhost/web 

从CAS服务端生成lt及execution，在cas的 login flow 中加入 ProvideLoginTicketAction 的流，主要用于判断该请求是否是来获取 lt，在cas-server端声明获取 login ticket action 类: 

org.jasig.cas.web.flow.ProvideLoginTicketAction 

import javax.servlet.http.HttpServletRequest;

import org.jasig.cas.util.UniqueTicketIdGenerator;
import org.jasig.cas.web.support.WebUtils;
import org.springframework.webflow.action.AbstractAction;
import org.springframework.webflow.execution.Event;
import org.springframework.webflow.execution.RequestContext;

/**
 * Opens up the CAS web flow to allow external retrieval of a login ticket.
 *
 * @author cydiay
 */
public class ProvideLoginTicketAction extends AbstractAction{

    private static final String PREFIX = "LT";

    @Override
    protected Event doExecute(RequestContext context) throws Exception {
        final HttpServletRequest request = WebUtils.getHttpServletRequest(context);
        if (request.getParameter("get-lt") != null && request.getParameter("get-lt").equalsIgnoreCase("true")) {
            final String loginTicket = this.ticketIdGenerator.getNewTicketId(PREFIX);
            WebUtils.putLoginTicket(context, loginTicket);
            return result("loginTicketRequested");
        }
        return result("continue");
    }

    private UniqueTicketIdGenerator ticketIdGenerator;

    public void setTicketIdGenerator(final UniqueTicketIdGenerator generator) {
        this.ticketIdGenerator = generator;
    }
}

并且将该 action 声明在 cas-servlet.xml 中： 

<bean id="provideLoginTicketAction" class="org.jasig.cas.web.flow.ProvideLoginTicketAction"
        p:ticketIdGenerator-ref="loginTicketUniqueIdGenerator"/>

还需要定义 loginTicket 的生成页也就是当返回 loginTicketRequested 的 view： 
位置/WEB-INF/view/jsp/default/ui 

viewRedirectToRequestor.jsp 

<%@ page contentType="text/html; charset=UTF-8"%>
<%
    String ajax = request.getParameter("n");
    //当执行Ajax自定义页面时执行以下操作
    if(ajax!=null && ajax.length()>0){
        response.getWriter().print(request.getAttribute("loginTicket")+"&"+request.getAttribute("flowExecutionKey"));
    } else {

    //正常cas执行
%>
     <script>window.location.href = "/cas/login";</script>
<%
    }
%>

并且需要将该 jsp 声明在 default._views.properites 中： 

casRedirectToRequestorView.(class)=org.springframework.web.servlet.view.JstlView
casRedirectToRequestorView.url=/WEB-INF/view/jsp/default/ui/viewRedirectToRequestor.jsp

接下来要做的就是将该action 的处理加入到 login-webflow.xml 请求流中: 

  <on-start>
      <evaluate expression="initialFlowSetupAction" />
  </on-start>

  <action-state id="provideLoginTicket">
      <evaluate expression="provideLoginTicketAction"/>
      <transition on="loginTicketRequested" to="viewRedirectToRequestor" />
      <transition on="continue" to="ticketGrantingTicketExistsCheck" />
  </action-state>

 <view-state id="viewRedirectToRequestor" view="casRedirectToRequestorView" model="credentials">
      <binder>
          <binding property="username" />
          <binding property="password" />
      </binder>
      <on-entry>
          <set name="viewScope.commandName" value="'credentials'" />
      </on-entry>
      <transition on="submit" bind="true" validate="true" to="realSubmit">
          <set name="flowScope.credentials" value="credentials" />
          <evaluate expression="authenticationViaFormAction.doBind(flowRequestContext, flowScope.credentials)" />
      </transition>
  </view-state>

  <decision-state id="ticketGrantingTicketExistsCheck">
<if test="flowScope.ticketGrantingTicketId != null" then="hasServiceCheck" else="gatewayRequestCheck" />
  </decision-state>

调整 CAS Server端，使其适应 Iframe 方式登录，并使其支持回调。 
打开 login-webflow.xml，找到 <action-state id="generateServiceTicket"> 的 Flow-Action 配置项: 

<!--当执行到该 action 的时候，表示已经登录成功，将生成 ST(Service Ticket)。-->
<action-state id="generateServiceTicket">
    <evaluate expression="generateServiceTicketAction" />
        <!--当生成 ST 成功后，则进入登录成功页，新增 loginResponse Action 处理项，判断是否是 ajax/iframe 登录 -->
        <!-- <transition on="success" to="warn" /> -->
        <transition on="success" to="loginResponse" />
        <!--<transition on="error" to="viewLoginForm" />-->
        <!-- 可能生成 service ticket 失败，同样，也是进入 loginResponse -->
        <transition on="error" to="loginResponse" />
        <transition on="gateway" to="redirect" />
    </action-state>

再新增 loginResponse Action配置项： 

<action-state id="loginResponse">
    <evaluate expression="ajaxLoginServiceTicketAction" />
    <!--非ajax/iframe方式登录，采取原流程处理 -->
    <transition on="success" to="warn" />
    <transition on="error" to="viewLoginForm" />
    <!-- 反之，则进入 viewAjaxLoginView 页面 -->
    <transition on="local" to="viewAjaxLoginView" />
</action-state>

再调整，当验证失败后，也需要判断是否是 iframe/ajax登录： 

<action-state id="realSubmit">
    <evaluate
        expression="authenticationViaFormAction.submit(flowRequestContext, flowScope.credentials, messageContext)" />
    <transition on="warn" to="warn" />
    <transition on="success" to="sendTicketGrantingTicket" />
    <!--将 to="viewLoginForm" 修改为 to="loginResponse" -->
    <transition on="error" to="loginResponse" />
</action-state>

还需要配置 viewAjaxLoginView 的 state:   

<end-state id="viewAjaxLoginView" view="viewAjaxLoginView" />

接着，再定义 ajaxLoginServiceTicketAction Bean 吧，直接在 cas-servlet.xml 声明该 bean: 

<bean id="ajaxLoginServiceTicketAction" class="com.unknow.cas.server.web.AjaxLoginServiceTicketAction"/>

import javax.servlet.http.HttpServletRequest;

import org.apache.commons.lang.BooleanUtils;
import org.apache.commons.lang.StringUtils;
import org.jasig.cas.authentication.principal.Service;
import org.jasig.cas.web.support.WebUtils;
import org.springframework.webflow.action.AbstractAction;
import org.springframework.webflow.execution.Event;
import org.springframework.webflow.execution.RequestContext;

public final class AjaxLoginServiceTicketAction extends AbstractAction {

    // The default call back function name.
    protected static final String J_CALLBACK = "feedBackUrlCallBack";

    protected Event doExecute(final RequestContext context) {
        HttpServletRequest request = WebUtils.getHttpServletRequest(context);
        Event event = context.getCurrentEvent();
        boolean isAjax = BooleanUtils.toBoolean(request.getParameter("isajax"));

        if (!isAjax){  // 非 ajax/iframe 方式登录，返回当前 event.
            return event;
        }
        boolean isLoginSuccess;
        // Login Successful.
        if ("success".equals(event.getId())){ //是否登录成功
            final Service service = WebUtils.getService(context);
            final String serviceTicket = WebUtils.getServiceTicketFromRequestScope(context);
            if (service != null){  //设置登录成功之后 跳转的地址
                request.setAttribute("service", service.getId());
            }
            request.setAttribute("ticket", serviceTicket);
            isLoginSuccess = true;
        } else { // Login Fails..
            isLoginSuccess = false;
        }

        boolean isFrame = BooleanUtils.toBoolean(request.getParameter("isframe"));
        String callback = request.getParameter("callback");
        if(StringUtils.isEmpty(callback)){ // 如果未转入 callback 参数，则采用默认 callback 函数名
            callback = J_CALLBACK;
        }
        if(isFrame){ // 如果采用了 iframe ，则 concat 其 parent 。
            callback = "parent.".concat(callback);
        }
        request.setAttribute("isFrame", isFrame);
        request.setAttribute("callback", callback);
        request.setAttribute("isLogin", isLoginSuccess);

        return new Event(this, "local"); // 转入 ajaxLogin.jsp 页面
    }
}

再定义一下 view 的页面地址，修改 default_views.properties，添加: 

viewAjaxLoginView.(class)=org.springframework.web.servlet.view.JstlView
viewAjaxLoginView.url=/WEB-INF/view/jsp/custom/ui/ajaxLogin.jsp

再是 ajaxLogin.jsp 的代码，从 request attributes 中获取到  ST, Service 等参数信息: 

<%@ page contentType="text/html; charset=UTF-8"%>
<html>
    <head>
        <title>正在登录....</title>
    </head>
    <body>
        <script type="text/javascript">
            <%
                Boolean isFrame = (Boolean)request.getAttribute("isFrame");
                Boolean isLogin = (Boolean)request.getAttribute("isLogin");
                // 登录成功
                if(isLogin){
                    if(isFrame){%>
                        //parent.location.replace('${service}?ticket=${ticket}')
                    <%} else{%>
                        location.replace('${service}?ticket=${ticket}')
                    <%}
                }
            %>
            // 回调
            ${callback}({'login':${isLogin ? '"success"': '"false"'}, 'msg': ${isLogin ? '""': '"用户名或密码错误！"'}})
        </script>
    </body>
</html>

然后客户端登录页面login.jsp: 

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Cas登录</title>
<script type="text/javascript" src="js/jquery.js"></script>
<script type="text/javascript" src="js/jquery.form.js"></script>
<script type="text/javascript">
    $(document).ready(function(){
        flushLoginTicket();  // 进入登录页，则获取login ticket，该函数在下面定义。
    });

    // 登录验证函数, 由 onsubmit 事件触发
    var loginValidate = function(){
        var msg;
        if ($.trim($('#J_Username').val()).length == 0 ){
            msg = "用户名不能为空。";
        } else if ($.trim($('#J_Password').val()).length == 0 ){
            msg = "密码不能为空。";
        }
        if (msg && msg.length > 0) {
            $('#J_ErrorMsg').fadeOut().text(msg).fadeIn();
            return false;
            // Can't request the login ticket.
        } else if ($('#J_LoginTicket').val().length == 0){
            $('#J_ErrorMsg').text('服务器正忙，请稍后再试..');
            return false;
        } else {
            // 验证成功后，动态创建用于提交登录的 iframe
            $('body').append($('<iframe/>').attr({
                style: "display:none;width:0;height:0",
                id: "ssoLoginFrame",
                name: "ssoLoginFrame",
                src: "javascript:false;"
            }));
            return true;
        }
    }

    // 登录处理回调函数，将由 iframe 中的页同自动回调
    var feedBackUrlCallBack = function (result) {
        customLoginCallBack(result);
        deleteIFrame('#ssoLoginFrame');// 删除用完的iframe,但是一定不要在回调前删除，Firefox可能有问题的
    };

    // 自定义登录回调逻辑
    var customLoginCallBack = function(result){
        // 登录失败，显示错误信息
        if (result.login == 'false'){
            $('#J_ErrorMsg').fadeOut().text(result.msg).fadeIn();
            // 重新刷新 login ticket
            flushLoginTicket();
        }else{
            //该处定义登录成功后需要执行的操作,比如刷新DIV等
            //......
            alert("登陆成功");
        }
    }

    var deleteIFrame = function (iframeName) {
        var iframe = $(iframeName);
        if (iframe) { // 删除用完的iframe，避免页面刷新或前进、后退时，重复执行该iframe的请求
            iframe.remove()
        }
    };

    // 由于一个 login ticket 只允许使用一次, 当每次登录需要调用该函数刷新 lt
    var flushLoginTicket = function(){
        var _services = 'service=' + encodeURIComponent('http://localhost/web/login.jsp');
        var casUrl = 'http://localhost:8080/cas/login?'+_services+'&get-lt=true&n=' + new Date().getTime();
        $.ajax({
            type: "GET",
            url: casUrl,
            success: function(data){
                var datadata = data.split('&');
                $('#J_LoginTicket').val(data[0]);
                $("#J_Execution").val(data[1]);
            }
        });
    }
</script>
</head>
<body>
    <form action="http://localhost:8080/cas/login" method="post" onsubmit="return loginValidate();" target="ssoLoginFrame">
    <ul>
        <li><span class="red" style="height:12px;" id="J_ErrorMsg"></span></li>

        <li>
            <em>用户名：</em>
            <input name="username" id="J_Username" type="text" style="width: 180px" />
        </li>
        <li>
            <em>密　码：</em>
            <input name="password" type="password"  id="J_Password" style="width: 180px" />
        </li>

        <li class="mai">
            <em>&nbsp;</em>
            <input type="checkbox" name="rememberMe" id="rememberMe" value="true"/>
            &nbsp;自动登录
            <a href="/retrieve">忘记密码？</a>
        </li>
        <li>
            <em>&nbsp;</em>
            <input type="hidden" name="isajax" value="true" />
            <input type="hidden" name="isframe" value="true" />
            <input type="text" name="callback" value="feedBackUrlCallBack" />
            <input type="text" name="lt" value="1" id="J_LoginTicket">
            <input type="text" name="execution" id="J_Execution" value="" />
            <input type="hidden" name="_eventId" value="submit" />
            <input name="" type="submit" value="登录" />
        </li>
    </ul>
</form>
</body>
</html>

Url中的service参数为登录成功后返回的页面,因为我在ajaxLogin.jsp页面并没有设置使用iframe时跳转，所以看到的结果是页面没跳转,但是设置该参数还是很有必要的。比如当使用spring security时，service=http://localhost/web/j_spring_cas_security_check ， 当登录成功时就会通过该URL对用户进行授权认证。 

至此，整个开发就算完成， 本人也是才开始学cas，该方法比较粗糙，但理解起来比较简单