Bases de données
warum verursacht php 5.2.6 nur probleme? html-seiten sehen so aus (ausschnitt):
beenden } } echo "\n"; echo "\n"; echo " \n"; echo " \n"; echo " \n"; echo " \n"; echo " \n"; echo " \n"; echo "
\n"; // ganz oberer Div-Holder echo "
\n"; echo " \n"; echo " \n"; echo " \n"; echo " \n"; echo "
\n"; echo " \n"; echo " \n"; echo " \n"; echo "
\n"; // banner echo "
\n"; echo " \n"; echo " \n"; echo " \n"; echo "
\n"; echo " \n"; echo "
\n"; echo " \n"; echo " \n"; echo " \n"; echo " hier werden die news erscheinen
php-seiten werden gar nicht mehr angezeigt nur 500 fehlermeldung.
und es liegt nicht am server. der fehler ist erst entstanden, nach dem die NEUE version installiert war.
Nouveau Modèle Objet
PHP 5 inclut un nouveau modèle objet. Le traitement des objets en PHP a complètement été réécrit pour arriver à de meilleures performances et plus de fonctionnalités. Dans les versions précédentes de PHP, les objets étaient traités comme des types primitifs (par exemple les entiers ou les chaînes de caractères). L'inconvénient de cette méthode était que sémantiquement, l'objet en entier était copié lorsqu'une variable était assignée ou passée comme paramètre à une fonction. Dans la nouvelle approche, les objets sont référencés par un pointeur et non pas leur valeur (on peut penser à un pointeur en tant qu'identifiant d'objet).
Beaucoup de développeurs PHP ne se rendent pas compte des caprices lors de la copie dans l'ancien modèle objet et, par conséquent, la majorité des applications PHP devrait fonctionner directement ou avec très peu de modifications.
Le nouveau modèle objet est documenté dans la partie de référence du langage.
En PHP 5, la fonction portant le nom d'une classe est appelée comme constructeur seulement si définit dans la même classe. En PHP 4, il sera également appelé s'il est définit dans la classe parent.
Voir aussi la directive zend.ze1_compatibility_mode pour la compatibilité avec PHP 4.
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User Contributed NotesNouveau Modèle Objet
antwort erwartet
08-Jun-2008 10:35
08-Jun-2008 10:35
zzo38
07-Oct-2007 05:06
07-Oct-2007 05:06
You should be able to clone a object in compatibility of PHP4,PHP5 with:
<?php
$x=unserialize(serialize($y));
?>
bdas at premiergroup dot uk dot com
25-May-2007 04:49
25-May-2007 04:49
Since PHP5 upgraded PHP to an OOP language, they CHANGED the metaphor so that when you copy an object, you just get a pointer to it (as in C# and Java) and so therefore they needed to make a way to CLONE objects as well in case you need a REAL copy of the object.
Most cases, clone is not needed, simply because a real copy of an object is usually not mandatory. In special cases, object cloning can be used to save time in porting.
quinn at strangecode dot com
19-May-2006 05:53
19-May-2006 05:53
Here is another possible solution for migrating code to php 5 when using $this = 'something' reassignments. In my case, I had several classes with methods that were self-instantiating with static calls. I was able to simply use a different variable: I changed $this to $_this and it worked the same because I copied an instance of the original object by reference using an instantiation factory method:
class DB {
function &getInstance()
{
static $instance = null;
if ($instance === null) {
$instance = new DB();
}
return $instance;
}
...
In every method needing access to this object I assigned it to a temporary variable by reference:
function doSomething ()
{
$_this =& DB::getInstance();
$_this->doSomethingElse();
$_this->param['id'] = 123;
}
Which allows method calls or saving data back to the original object.
I originally created classes like this so I didn't need to keep track of instantiations or global objects. I could just call DB::doSomething() and the object is created dynamically or referenced from an already existing object.
riseofthethorax at yahooo dot com
29-Sep-2005 03:53
29-Sep-2005 03:53
I actually understand the addressing modes in 4.3 and use them, it hasn't bothered me.. Like I have objects within objects, each with variables containing references (like pointers but without the pointer arithmetic). I can obtain an object group from the database, obtain the method interface to a subobject, issue a manipulation through the child, then store the object group back into the database with the manipulation intact.. I'm not sure what effect the new changes will have on this, but if its drastic, I'm not sure I can support 5.0.
A nice little userlevel way of messing with PHP's addressing,
the use of aliases:
// I haven't coded in PHP for a while so sue me
class stuff {
var $stuff;
function stuffer() {
$null = NULL;
$s = &$this->stuff;
$s = "some stuff";
$s = &$null;
}
}
This works.. You can make some assumptions about
what is going on behind the scenes, especially
what $s is before being assigned a reference to
another variable and after.. Its either two kinds of things,
a reference to a variable or a container of data, or
its a reference to a data location at all times, just that by default it gets an address to a string and at other times it can be assigned the address of objects. The "&" redirects where its pointing. At least this is how I think about it.
I use this side-effect all the time for making aliases in my objects..
Kiernan
hairmare-spam at purplehaze dot ch
10-Jun-2005 01:41
10-Jun-2005 01:41
I have noted some discussion going on about the 'Cannot re-assign $this' error.
The most simple way to reproduce the error is:
class MyObject
{
function test()
{
$this = new MyObject;
}
}
I found the following quote (quoting zend.com) on php-dev:
http://www.zend.com/php/ask_experts.php :
"The fact that you could change in PHP 4, was never really meant to be
although it worked. In PHP 5 we removed this option due to performance
and semantic reasons. In PHP 5, you can either use a factory method
pattern or throw an exception on error in the constructor."
This statement implies that the error lies not in PHP5 but in the script. A Bogus Bug in http://bugs.php.net/bug.php?id=27659 tells me the same thing.
There has been some discussion on how to migrate such code to php5 without having to reengineer the whole App. From my point of view the following solutions are viable:
1. Use delegation & Object composition:
$this->Object = new Whatever();
function nameOfFunction()
{
return $this->Object->nameOfFunction();
}
This requires lots of code rewriting. Some of it could be realised with overloading. Variables would need to get overloaded or could only be accessed using a getter/setter. As a xtra you get clean OO Code!
2. Replace Original Objects Content:
foreach (get_object_vars($foo) as $key => $value)
$this->$key = $value;
This solution only works with instance-variables. Additional classkit/runkit code would be needed to get everything else correct. This way less refactoring would be needed. This could be the right way to go if you don't need to replace any methods or the classname.
I haven't decided wich way to go. I wrote this so the next hacker with this problem finds some info where I was looking for it.
ivanildo at kowsoleea.de
23-May-2005 11:56
23-May-2005 11:56
It seems that simpleXML functions like 'simplexml_load_file' do not work in ze1 compatibility mode due to some cloning 'features' I do not yet understand.