php 用户登陆代码，入门教程

php 用户登陆代码，入门教程
function login_xzy()
{
$user_=db("user");
$session_=db("session");
$login['email']=strip_tags($_POST['email']);
$login['pass']=empty($_POST['pass'])?"":md5($_POST['pass']);
if($user=$user_->where("`email`='{$login['email']}' and `pass`='{$login['pass']}'")->find()){
if($session_->where("`uid`='{$user['uid']}'")->find()){
$json['status']=1;
$json['info']='已登陆的会员!';
}else{
$user['total']++;
$user_->where("`uid`='{$user['uid']}'")->update(array('total'=>$user['total'],'lastip'=>ip2long(getip()),'lasttime'=>time() ));
$session_->where("session_id='".Session_id()."'")->update(array('uid'=>$user['uid']));
$_SESSION['user']=$user;
$json['data']=$user;
$json['status']=0;
}
}else{
$json['status']=1;
$json['info']='用户名或密码不正确!';
}
echo json_encode($json);
}