PHP: json_encode vs serialize for storing in a MySQL database?

Question

I'm storing some "unstructured" data (a keyed array) in one field of my table, and i'm currently using serialize() / unserialize() to "convert" back and forth from array to string.

Every now and then, however, I get errors when unserializing the data. I believe these errors happen because of Unicode data in the strings inside the array i'm serializing, although there are some records with Unicode data that work just fine. (DB field is UTF-8)

I'm wondering whether using json_encode instead of serialize will make a difference / make this more resilient. This is not trivial for me to test, since in my dev environment everything works well, but in production, every now and then (about 1% of records) I get an error.

Btw, I know i'm weaseling out of finding an actual explanation for the problem and just blindly trying something, I'm kind of hoping I can get rid of this without spending too much time on it.

Do you think using json_encode instead of serialize will make this more resilient to "serialization errors"? The data format does look more "forgiving" to me...

UPDATE: The actual error i'm getting is:

 Notice: unserialize(): Error at offset 401 of 569 bytes in C:\blah.php on line 20

Thanks! Daniel

Answer 1

JSON has one main advantage :

• compatibility with other languages than PHP.

PHP's serialize has one main advantage :

• it's specifically designed to store PHP-based data -- most notably, it can store serialized objects, instance of classes, that will be re-instanciated to the right class-type when the string is unserialized.

(Yes, those advantages are the exact opposite of each other)

In your case, as you are storing data that's not really structured, both formats should work pretty well.

And the encoding problem you have should not be related to serialize by itself : as long as everything (DB, connection to the DB, PHP files, ...) is in UTF-8, serialization should work too.