Question

I’m trying to serialize a Doctrine_query object in Symfony :

var_dump(serialize($this->pager->getQuery()));

The result is :

string(2) "N;"

What am I doing wrong?

Answer 1

You can not serialize every object in PHP. Objects themselves – by implementing the Serializeable interface ^{PHP Manual} – can protect themselves from being serialized for example.

They return a NULL value then (or don’t return anything which is then NULL in PHP). And that’s exactly the contents of your serialized string: a serialized NULL (N;).

And there are even some build-in classes that go even further than that. But it applies as well to user-defined classes and build-in classes: Some of them are not available for serialization.

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One example of a built-in class that can not be serialized in PHP is DOMDocument, however it is possible to add the functionality as the following question demonstrates:

• How to serialize/save a DOMElement in $_SESSION?.