php 用户注册与登陆程序

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php 用户注册与登陆程序
 function islogin_xzy()
 {
  if(!isset($_SESSION['user'])){
   $json['status']=1;
  }else{
   $ssess_=db("session as s");
   $where="s.session_id='".Session_id()."' and u.uid is not null";
   if($user=$ssess_->join("`user` as u on u.uid=s.uid")->field("u.*,s.session_id,s.uid")->where($where)->find()){
    $json['status']=0;
    $json['data']=$user;
   }else{
    $json['status']=1;
   }
  }
  echo json_encode($json);
 }

 function reg_xzy()
 {
  $user_=db("user");
  $reg['email']=strip_tags($_POST['email']);
  $reg['pass']=empty($_POST['pass'])?"":md5($_POST['pass']);
  $reg['sex']=$_POST['sex']=='男' || $_POST['sex']=='女'?$_POST['sex']:'';
  $reg['nickname']=strip_tags($_POST['nickname']);
  $reg['regip']=ip2long(getip());
  $reg['regtime']=time();
  $i=0;
  foreach($reg as $v){
   if(!empty($v)) $i++;
  }
  if($i!=6){
   $json['status']=1;
   $json['info']='注册项不全!';
  }elseif($user_->where("`email`='{$reg['email']}'")->find()){
   $json['status']=1;
   $json['info']='已注册的email地址!';
  }elseif($uid=$user_->insert($reg)){
   $session_=db("session");
   $session_->where("session_id='".Session_id()."'")->update(array('uid'=>$uid));
   $sessionas_=db("session as s");
   $where="s.session_id='".Session_id()."' and s.uid is not null";
   if($user=$sessionas_->join("user as u on u.uid=s.uid")->field("u.*,s.session_id,s.uid")->where($where)->find()){
    $_SESSION['user']=$user;
    $json['data']=$user;
    $json['status']=0;
   }else{
    $json['status']=1;
    $json['info']='自动登陆出错，请人工登陆!';
   }
  }else{
   $json['status']=1;
   $json['info']='注册失败!';
  }
  echo json_encode($json);
 }

 function logout_xzy()
 {
  $session_=db("session");
  $session_->where("session_id='".Session_id()."'")->update(array("uid"=>null));
  session_destroy();
 }