PHP: array of objects - serialize vs json_encode - alternatives?

Question

In PHP, it is very difficult for me to use serialize / unserialize for a large array of objects (100000+ objects). These objects can be of different types, but they are all descendants of the base class.

Somehow, when I use unserialize in an array of objects, about 0.001% of the objects are generated incorrectly! Instead, a whole other object is generated. This does not happen randomly, but each time with the same objects. But if I change the order of the array, this happens with different objects, so it looks like an error to me.

I switched to json_encode / json_decode , but found that it always uses stdClass as an object class. I solved this by including the class name in each object as a property, and then use this property to create a new object, but this solution is not very elegant.

Using var_export with eval works fine, but is about 3 times slower than other methods and uses a lot more memory.

Now my questions are:

• what can cause errors / wrong objects created using unserialize ?
• Is there a better way to use json_decode with an array of objects, so that classes are somehow stored in json automatically?
• Is there perhaps another method for reading / writing a large array of objects in PHP?

UPDATE

I'm starting to believe that there should be something strange with my data arrays, because with msgpack_serialize (php extension, alternative to serialize ) I get the same errors (but oddly enough the same objects are not generated correctly!).

UPDATE 2

Found a solution: instead of doing serialize in the whole array, I do it on every object now, first serialize and then base64_encode , and then I store each serialized object as a separate line in a text file, a file. That way I can generate the entire array of objects and then iterate over each object with file() using unserialize and base64_decode : more errors!

Answer 1

Using the serialization / non-serialization functions, 2 magic methods are connected.

__ sleep ()

serialize () checks if your class has a function with the magic name __sleep (). If so, this function is executed before any serialization. It can clear an object and must return an array with the names of all the variables of this object that must be serialized. If the method returns nothing, then NULL is serialized and E_NOTICE is returned.

With a sonny, you better control serialization, you can pass variables that can be serialized, and clean resources that provide serialization.

When calling unserialize, another function must be specified.

__ wakeup ()

The intended use of __wakeup () is to restore any database connections that might be lost during serialization and other reinitialization tasks.

About json_encode ()

• It has no magic methods __wakeup, __sleep, so you have less control.
• It does not serialize private properties.
• Objects are always saved as stdClass
• Json_encode is faster than serializing

It is up to you what you choose, but for more advanced classes with db connection, etc. I would suggest serialize ()