where to write custom functions and how to import them?

here is my little story: I am using DoctrinExtensions Tree on my entity account. The user can edit the tree in the UI and then save it. I send back back to the PHP an array of all the accounts. Then I want to rebuilt it as a tree and save/edit the accounts with the methods of the extension.

So I want to compare the UI returned array with my original tree from the db. I get the data by doing something like this:

$repo = $em->getRepository('NRtworksChartOfAccountsBundle:Accounttree');
$arrayTree = $repo->findAll(); 

So I have my tree in an array. What I want now is to find an object within this array by itsd ID. I know how to write the function, but in the MVC I don't know what's the right place to write it and call it from, nor if it's the correct way.

I tried to create a folder "Model" and a file Functions.php like this:

 namespace NRtworks\ChartOfAccountsBundle\Model;

 function get_account_from_id($array)
 {
    return "true";    
 }

and then call it from my controller

use NRtworks\ChartOfAccountsBundle\Model\Functions;
get_account_from_id($arrayTree);

But that doesn't work. Please advise on how I should do this and if there is a more correct way in the scope of the MVC idea.

thanks

You should write custom service and put logic inside. Doc: http://symfony.com/doc/current/book/service_container.html#what-is-a-service

UPDATE (Code example):

Les's configure service in the Container:

# app/config/config.yml
services:
    your_service:
        class:        NRtworks\ChartOfAccountsBundle\Service\YourService

Now, your service class:

namespace NRtworks\ChartOfAccountsBundle\Service;

class YourService {
    public function getAccountFromId(array $array)
    {
        return "true";
    }
}

Now you could get this service from container like:

class SomeController extends Controller {
    public function someMethod() {
        $yourService = $this->get('your_service');
    }
}

You can even inject your repository class to this service, like:

# app/config/config.yml
services:
    app.accounTtree.repository:
        class:           Doctrine\ORM\EntityRepository
        factory-service: doctrine.orm.entity_manager
        factory-method:  getRepository
        arguments: 
            - "App\MainBundle\Entity\Gallery"

    your_service:
        class:        NRtworks\ChartOfAccountsBundle\Service\YourService
        calls: 
            - [ setRepository, ["@app.accounTtree.repository"]]

and just modify your service:

namespace NRtworks\ChartOfAccountsBundle\Service;

class YourService {
    protected $repository;

    public class setRepository($repository) {
        $this->repository = $repository;
    }

    public function getAccountFromId(array $array)
    {
        return "true";
    }
}