What's the best way of sending a PDO between actions in Symfony2?

Question

In a controller's action I load a PDO object from the database and send it to the twig template in order to render a data grid:

/**
 * @Route("/action1", name="action1")
 * @Template()
 */
public function action1Action(Request $request)
{
    $mydata = $this->daoClass->getData();
    return array(
        'mydata' => $mydata
    );
}

$myData is loaded using Doctrine which returns me a PDO object with an (small) array of results (PDO Object). I render this like this:

<table>
    {% for data in mydata %}
        <tr>
            <td>{{ data.foo }}</td>
            <td>{{ data.bar }}</td>
        </tr>
    {% endfor %}
</table>

So in the twig template, below the table with the data, I got this form that sends data to the next action:

<form action="{{ path('action2') }}" method="post">
    <!-- some javascript populated fields -->
    <input type="hidden" id="field1" name="field1">
   ...
</form>

How can I make it send also the PDO object that rendered the grid (mydata object) ?

I tried to insert it in the session in the first action so I can retrieve it in the next action but got the message: "You cannot serialize or unserialize PDO instances"

Is there any better way to do this ?

I'm not using symfony forms in this module because this is an overly complex screen with lots of validations and calculated fields and it would be much more complicated to use the forms.

Answer 1

Is there any better way to do this ?

Yes with symfony forms.

I'm not using symfony forms in this module because this is an overly complex screen with lots of validations and calculated fields and it would be much more complicated to use the forms.

As complex as you want. Using symfony forms for mapping, the view and with the symfony validation are very very powerful tools. Writing your own forms and mapping and validations is unnecessary.

What's the best way of sending a PDO between actions in Symfony2?

The answer is definitely not to save Doctrine entities to a session or Memcache and the reason is:

// copied from the comment

Think in scopes. PHP starts, does something, terminates. You can only hold data whose scope is not limited. For example a simple string has no scope. You can only store such type of data, but no smart PDO objects. For example doctrine entities are actually only some attributes with getters and setters, but doctrine is doing some magic to implement a proxy-pattern for them. Thus they extend some accessing logic saying if any setter or getter is invoked, load the object from the database first. If you would store them and reload them, they would have dead references to the objects.

Answer 2

First of all, don't do what you're trying to do for performance reasons.

What you're trying to do is called premature optimization, and it is not good.

Someone here tried to do a very similar thing to what you're doing and they are having a hard time.

However, if you ever want to store information the user temporarily to another page use Symfony Sessions

In case you skip what I said, let me repeat:

Warning: This code is NOT recommended for PDO results

use Symfony\Component\HttpFoundation\Session\Session;

$session = new Session();
$session->start();

// set and get session attributes
//Controller ExampleMethodAction1()
$Person = new Person();
$Person->setName('John');
$session->set('PersonObject', $Person);


//Then in another controller method
//Controller ExampleMethodAction2()
$Person = $session->get('PersonObject');
$Person->getName(); //returns John

Another thing about performance is, it's cheaper to buy more hardware than hire a new developer to optimize the code.