Share a PHP User login class

In PHP programming, user login is often used, here to share a good PHP user login class, the need for a friend reference. PHP User Login class, code: Errreport ($this->err_mysql); $this->err= $this->err_mysql; }} function isLoggedIn ()//determine if login {if (isset ($_cookie[' sid '))//If the COOKIE has SID { session_id ($_cookie[' Sid '); Session_Start (); $this->username=$_session[' username ']; $this->userid=$_session[' userid ']; $this->userlevel=$_session[' userlevel ']; return true; } else//If the SID is not saved in the cookie, check the session {session_start () directly; if (isset ($_session[' username ')) return true; } return false; } function Userauth ($username, $userpass)//user authentication {$this->username= $username; $this->userpass= $userpass; $query = "SELECT * from". $this->authtable. " ' WHERE ' username ' = ' $username '; "; $result =mysql_query ($query); if (mysql_num_rows ($result)!=0)//Find this user {$row =mysql_fetch_array ($result); if ($row [' bannd ']==1)//This user is banned {$this->errreport ($this->err_user); $this->err= $this->err_user; return false; } elseif (MD5 ($userpass) = = $row [' userpass '])//password match {$this->userid= $row [' id ']; $this->userlevel= $row [' userlevel ']; return true; } else//password mismatch {$this->errreport ($this->err_password); $this->err= $this->err_password; return false; }} else//did not find this user {$this->errreport ($this->err_username); $this->err= $this->err_username; return false; }} function Setsession ()//Set Session {$sid =uniqid (' Sid '); Generate SID session_id ($SID); Session_Start (); $_session[' username ']= $this->username; Assigning a value to a session variable $_session[' userid ']= $this->userid; //.. $_session[' userlevel ']= $this->userlevel; //.. if ($this->use_cookie)//Use cookies to save Sid {if (!setcookie (' Sid ', $sid, Time () + $this->cookietime, $th Is->cookiepath)) $this->errreport ("Set Cookie Failed"); } else Setcookie (' Sid ', ', Time ()-3600); Clears the SID in the cookie} function Userlogout ()//user logoff {session_start (); unset ($_session[' username '); Clears the username if in session (Setcookie (' Sid ', ", Time ()-3600))//Clears the SID in the cookie to return true; else return false; } function Errreport ($STR)//error {if ($this->error_report) echo "error: $str"; }}?>

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