从PHP4到PHP5：会话处理程序无法访问全局数据库对象

Question

I am migrating a PHP app written many, many years ago in PHP 4.4 to a new host that runs PHP 5.3. The app was written using only the PEAR libraries and no other framework. I'm finding the following problem: I have in my main page this code:

require_once('DB.php'); //the PEAR DB package

$db=DB::connect("mysql://usuario:@localhost/databasename");
if (DB::isError($db)) {
    die("MEEEEEPT");
    }

//Inicia sesión
session_set_save_handler("Sesion_Open", "Sesion_Close", "Sesion_Read", "Sesion_Write", "Sesion_Delete", "Sesion_Clean");
session_name("misesion");
session_start();

And then, the session handlers are:

function Sesion_Open() {

    global $db;

    if (DB::isConnection($db)) { return true; }
    else { return false; }
    }

function Sesion_Close() {

    global $db;

    $db->disconnect();
    return true;
    }

function Sesion_Read($id) {

    global $db;

    $resultado=$db->query("SELECT datos FROM sesiones WHERE id='$id'");
    $num=$resultado->numRows();
    if ($num > 0) {
        $row=$resultado->fetchRow(DB_FETCHMODE_ASSOC);
        $resultado->free();
        return $row['datos'];
        }
    else {
        $resultado->free();
        return "";
        }
    }

function Sesion_Write($id, $datos) {

    global $db;

    $datos=addslashes($datos);
    $num=$db->getOne("SELECT COUNT(id) FROM sesiones WHERE id='$id'");
    if ($num > 0) {
        $sql="UPDATE sesiones SET datos='$datos', tiempo=now() WHERE id='$id'";
        }
    else {
        $sql="INSERT INTO sesiones (id, tiempo, datos) VALUES ('$id', now(), '$datos')";
        }
    $resultado=$db->query($sql);
    if (DB::isError($resultado)) { return false; }
    else { return true; }
    }

If I try to save some data in the session, using, say:

$_SESSION['bkla']="Doremifa";

It doesn't get saved: the DB sessions table remains empty, and I get an error in the log saying:

 PHP Fatal error:  Call to a member function getOne() on a non-object in sesiones.php on line 45

Referring to the line in "Sesion_Write" where I try to do a SELECT on the table.

From what I see, the "Sesion_Open" function can access correctly the $db object, but the others can't see it; the object doesn't seem to exist for them. What's going on? I haven't touched PHP in a few years, so I don't know if something changed between PHP4 and PHP5 to cause this, or there's something else.

Answer 1

Ah, found the answer:

Strange behaviour migrating sessions with callbacks from php4 to php5

You need to either call session_write_close() by hand, or register it as a shutdown function: register_shutdown_function("session_write_close") .