PHP 会话类 OOP

Question

I seem to be having problems logging in using the session variable name from the session class. I don't know what code I'm missing. The welcome page wont pick up the user logged in. below is the code.

class Session
{
   private $message;
   function __construct()
   {
      session_start();

   }

   function getVariable($varname)
   {
      if(isset($_SESSION['$varname'])) #17
      return $_SESSION['$varname'];
      else #19
      {
         $this->message = "No such variable in
         this session";
         return FALSE;
      }
   }

   function storeVariable($varname,$value)
   {
      if(!is_string($varname)) #29
      {
         throw new Exception("Parameter 1 is not a
         valid variable name.");
         return FALSE;
      }
      else
      $_SESSION['$varname'] = $value;
   }

   function getMessage()
   {
      return $this->message;
   }

   function login(Account $acct,$password) #44
   {
      if(!$acct->comparePassword($password)) #46
       {
          return FALSE;
       }
       $this->storeVariable("user_name", "user_name"); #47

       return TRUE;
    }


}

The following is the code for the login page were I call the session object

//First time form is displayed. Form is blank. //
if (!isset($_POST['Button'])) #26
  {
    $form->displayForm();
    exit();
  }
// Process form that has been submitted with user info //
  else
{
   $sess = new Session(); #34

   try
   {
      $db = new Database("verybig.data"); #37
      $db->useDatabase("database"); #38
      $acct = new Account($db->getConnection(),"user");
   }
   catch(Exception $e)
   {
   echo $e->getMessage()."\n<br>";
   exit();
   }

 if(!$sess->login($acct,$_POST['password'])) #76
   {
      $GLOBALS['message_1'] = $acct->getMessage().
      " Please try again.";
      $form->displayForm();
      exit();

   }


   header("Location: companyhome.php"); #83
   exit();
try
{
  if($acct->selectAccount($newdata['user_name'])) #140
   {
     $GLOBALS['message_2'] =
       "Member ID already used.
            Select a new Member ID.";
     $form->displayForm();
     exit();
   }

   if(!$acct->createNewAccount($newdata)) #148
   {
      echo "Couldn’t create new account.
        Try again later.";
      exit();
   }

   $sess->storeVariable("user_name", $newdata['user_name']); #154
   $sess->storeVariable("user_dept", $newdata['dept_id']);

And here is the part were I want the stored session variable to appear on the welcome page. Here the welcome page just wont pick up the stored session variables. Question is how can the session variables be passed on to this page

if (!isset($_SESSION))
session_start();



echo $_SESSION['user_name']. "<br>";



$admin = FALSE;
$base_url = "companyhome.php";
$trail = "<a href='$base_url'>Home</a>";
if (!isset($_SESSION['user_name']))
header("Location: login-oo.php");#31
else
{
if (isset($_SESSION['user_name'])
&& isset($_GET['dept_id']))
{
$admin = $_SESSION['user_dept'] == $_GET['dept_id'];
}
$left_nav_links = array();
$page["browse_level"] =
isset($_GET['browse_level']) ?
$_GET['browse_level'] : "home";

Here is a little bit of code from the account class

class Account
{
private $user_name = NULL;
private $cxn; // database connection object
private $table_name;
private $message;
function __construct( mysqli $cxn,$table)
{
$this->cxn = $cxn;
if(is_string($table)) #17
{
$sql = "SHOW TABLES LIKE '$table'"; #19
$result = $this->cxn->query($sql);
if($result->num_rows > 0) #21
{
$this->table_name = $table;
}
else #25
{
throw new Exception("$table is not a table
in the database");
return FALSE;
}
}
else #32
{
throw new Exception("Second parameter is not a
valid table name");
return FALSE;
}
}
function selectAccount($user_name)
{
$user_name = trim($user_name); #42
$sql = "SELECT user_name FROM $this->table_name
WHERE user_name ='$user_name'"; #44
if(!$result = $this->cxn->query($sql))
{
throw new Exception("Couldn't execute query: "
.$this->cxn->error());
return FALSE;
}
if($result->num_rows < 1 ) #51
{
$this->message = "Account $user_name
does not exist!";
return FALSE;
}
else #57
{
$this->user_name = $user_name;
return TRUE;
}
}
function comparePassword($password)
{
if(!isset($this->user_name)) #66
{
throw new Exception("No account currently selected");
exit();
} #70
$sql = "SELECT user_name FROM $this->table_name
WHERE user_name ='$this->user_name' AND
password = md5('$password')";
if(!$result = $this->cxn->query($sql)) #74
{
throw new Exception("Couldn't execute query: "
.mysql_error());
exit();
}
if($result->num_rows < 1 ) #80
{
$this->message = "Incorrect password for
account $this->user_name!";
return FALSE;
}
else #86
return TRUE;

}

Answer 1

I'm not going to start debugging your code for you - you may wish to read up on how to create a MCVE , but there is at least one glaring error here:

if(isset($_SESSION['$varname'])) #17

Those should be double quotes or no quotes.

(There are lots of things which can go wrong with PHP sessions - if you search some of the answers here you'll find out how to detect and remediate them)