php项目的index.php文件，项目是原生php写的

<?php

require( dirname(__FILE__) . '/config.php' );

global $GLOBAL_SYSTEM;


if(isset($_GET['userId']) && $_GET['userId'] != ""){
    $user_name = $_GET['userId'];
    $param = '<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:lev="http://session.level1.services.sdk.actionsoft.com/">
   <soapenv:Header><aws-auth xmlns="http://services.sdk.actionsoft.com/">fecaca56a326610b24626b163814a02c</aws-auth>
<soapenv:Header/>
   <soapenv:Body>
      <lev:checkSession>
         <userId>'.$_GET['userId'].'</userId>   <sid>'.$_GET['sid'].'</sid>
      </lev:checkSession>
   </soapenv:Body>
</soapenv:Envelope>';

    
    $sessionServer = "http://mzwa-123.6655.la:8090/services/SessionService";
    if(defined('SSO_SESSION_SERVER')){
        $sessionServer = SSO_SESSION_SERVER;
    }
    
    $securityServer = "http://mzwa-123.6655.la:8090/services/SecurityService";
    if(defined('SSO_SECURITY_SERVER')){
        $securityServer = SSO_SECURITY_SERVER;
    }
    
    $xmls = fetch($sessionServer, $param);
    
    if($xmls === false){
        sd_redirect($GLOBAL_SYSTEM[PRODUCT_TYPE]["index"]);
    }
    
    $xml_values = "";
    
    $parser = xml_parser_create('UTF-8');
    xml_parse_into_struct($parser, trim($xmls), $xml_values);
    xml_parser_free($parser);

    
    foreach ($xml_values as $value){
        if($value['tag'] == "RETURN"){
            if($value['value'] == 'false'){
                sd_redirect($GLOBAL_SYSTEM[PRODUCT_TYPE]["index"]);
            }elseif($value['value'] == 'true'){
                $user = &sd_get_user($user_name);
                if (!empty($user) ) {
                    $result = login_without_pwd_verify($user);
                    $_SESSION["user"] = $user_name;
                    if ($_SESSION["role"] == UserDao::$ROLE_CLOUD_USER) {
                        if (I2System::isI2Cloud()){
                            sd_redirect("cloud/home.php");
                        }else{
                            sd_redirect($GLOBAL_SYSTEM[PRODUCT_TYPE]["index"]);
                        }
                    } else {
                        sd_redirect("i2/home.php");
                    }
                }
            }
            break;
        }
    }
}else{
    sd_redirect($GLOBAL_SYSTEM[PRODUCT_TYPE]["index"]."?".$_SERVER["QUERY_STRING"]);
}

---

整体流程上来讲, 是从GET请求中得到 userId,
然后检测这个userId是否有值, 如果没有值则跳回首页.
如果有值, 则拼出来一个XML结构的东东(应该是调用 WebService),
然后再根据是否有定义 SSO_SESSION_SERVER 决定使用默认的,还是定义好的 SessionService 地址.
然后发起请求,
如果请求失败了, 则跳转回首页.
否则再根据请求的结果,决定跳到哪个页面.

<?php

//应该是引入配置文件
require( dirname(__FILE__) . '/config.php' );

global $GLOBAL_SYSTEM;


//检测是否有通过 GET 方式传递过来 userId
if(isset($_GET['userId']) && $_GET['userId'] != ""){//如果有传,则if条件成立
    $user_name = $_GET['userId'];//得到传递过来的 userId
    //拼出来XML
    $param = '<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:lev="http://session.level1.services.sdk.actionsoft.com/">
   <soapenv:Header><aws-auth xmlns="http://services.sdk.actionsoft.com/">fecaca56a326610b24626b163814a02c</aws-auth>
<soapenv:Header/>
   <soapenv:Body>
      <lev:checkSession>
         <userId>'.$_GET['userId'].'</userId>   <sid>'.$_GET['sid'].'</sid>
      </lev:checkSession>
   </soapenv:Body>
</soapenv:Envelope>';

    //默认 sessionServer 的地址
    $sessionServer = "http://mzwa-123.6655.la:8090/services/SessionService";
    //如果有定义 SSO_SESSION_SERVER 的常量
    if(defined('SSO_SESSION_SERVER')){//则更新 $sessionServer 的值为 SSO_SESSION_SERVER 的值
        $sessionServer = SSO_SESSION_SERVER;
    }
    
    //这里的代码没地方用, 所以就加注释了
    $securityServer = "http://mzwa-123.6655.la:8090/services/SecurityService";
    if(defined('SSO_SECURITY_SERVER')){
        $securityServer = SSO_SECURITY_SERVER;
    }
    
    //应该是发起一个HTTP请求
    $xmls = fetch($sessionServer, $param);
    
    //如果请求失败了
    if($xmls === false){
        //跳到某个页面(应该是首页什么的)
        sd_redirect($GLOBAL_SYSTEM[PRODUCT_TYPE]["index"]);
    }
    
    $xml_values = "";
    
    //解析请求回来的内容
    $parser = xml_parser_create('UTF-8');
    xml_parse_into_struct($parser, trim($xmls), $xml_values);
    xml_parser_free($parser);

    //遍历得到的XML文件
    foreach ($xml_values as $value){
        if($value['tag'] == "RETURN"){//如果数据中的 tag 等于 RETURN
            if($value['value'] == 'false'){//数据中的 value 为 false 时
                sd_redirect($GLOBAL_SYSTEM[PRODUCT_TYPE]["index"]);//跳到某个页面
            }elseif($value['value'] == 'true'){//为 true 时
                $user = &sd_get_user($user_name);//再调用某个方法(传递最上面得到的 userId 过去)
                if (!empty($user) ) {//如果 sd_get_user 的返回值不是空的
                    $result = login_without_pwd_verify($user);//再调用某个方法, 传递 上面的返回值过去
                    $_SESSION["user"] = $user_name;
                    if ($_SESSION["role"] == UserDao::$ROLE_CLOUD_USER) {//再判断
                        if (I2System::isI2Cloud()){//再判断...
                            sd_redirect("cloud/home.php");//条件成立时跳这里
                        }else{
                            sd_redirect($GLOBAL_SYSTEM[PRODUCT_TYPE]["index"]);//不成立时跳这里
                        }
                    } else {//if不成立时跳这里
                        sd_redirect("i2/home.php");
                    }
                }
            }
            break;
        }
    }
}else{
    //没有 userId 时,跳这里...
    sd_redirect($GLOBAL_SYSTEM[PRODUCT_TYPE]["index"]."?".$_SERVER["QUERY_STRING"]);
}