How to echo a php code using ob_start in another function?

Question

I've tried to copy my php code from foreach loop using ob start but failed. Does anyone knows how to do this? I wanted to add my php code in another function like below.

foreach($kekei as $good => $goodness) { 

                        ob_start();

                        $GLOBALS['myfirstbowanstart'] .= "if ( $packing_fee === 'strtolower(".$goodness['shipping_code'].")' ) {
                        $label = __('Shipping fee');
                        $cost  = ".$goodness['shipping_fee'].";
                        }"; // put here your recursive function name

                        ob_get_clean();

                    }

// Add a custom dynamic packaging fee
add_action( 'woocommerce_cart_calculate_fees', 'add_packaging_fee', 20, 1 );
function add_packaging_fee( $cart ) {
    if ( is_admin() && ! defined( 'DOING_AJAX' ) )
        return;

    //$domain      = "woocommerce";
    $packing_fee = WC()->session->get( 'the_chosen_one' ); // Dynamic packing fee


    echo $GLOBALS['myfirstbowanstart'];

/*
    if ( $packing_fee === 'gzeatp1' ) {
        $label = __("Shipping fee");
        $cost  = 3.00;
    } elseif ( $packing_fee === 'box' ) {
        $label = __("Shipping fee");
        $cost  = 9.00;
    }
*/
    if ( isset($cost) )
        $cart->add_fee( $label, $cost );
}

Answer 1

<?php
$GLOBALS = array("results"=>array(), "tests" => array("test1", "test2", "test3"));
$label = $cost = "";
$packing_fees = array("gzeatp1" => "3.00", "box" => "9.00", "cotton" => "12.00");


$packing_fee = "cotton";   //WC()->session->get( 'the_chosen_one' );


$kekei = array(
                "first_good" => array("param1" => "value1", "shipping_code" => "gzeatp1"),
                "second_good"=> array("param2" => "value2", "shipping_code" => "box"),
                "third_good" => array("param3" => "value3", "shipping_code" => "cotton"),
              );


$callback =  
        function ($shipping_code, $packing_fee) use ($cost, &$packing_fees)
        {
            if($packing_fee === strtolower($shipping_code)) { 
               $label = 'Shipping fee';
               $cost = $packing_fees[$shipping_code];

               $GLOBALS["results"] = array("label" => $label, "cost"=> $cost);
            }
        };


foreach($kekei as $good => $goodness) { 
   $callback($goodness['shipping_code'], $packing_fee) ;
} 

// Add a custom dynamic packaging fee
//add_action( 'woocommerce_cart_calculate_fees', 'add_packaging_fee', 20, 1 );

function add_packaging_fee( $cart = "" ) {
    //Disabled for testing
    #if ( is_admin() && ! defined( 'DOING_AJAX' ) )
    #    return;

    //$domain      = "woocommerce";
    //$packing_fee = WC()->session->get( 'the_chosen_one' ); // Dynamic packing fee

// If $label and $cost are global variables, comment out next 2 lines.
    $label = $GLOBALS["results"]["label"];
    $cost = $GLOBALS["results"]["cost"];

/*
    if ( $packing_fee === 'gzeatp1' ) {
        $label = __("Shipping fee");
        $cost  = 3.00;
    } elseif ( $packing_fee === 'box' ) {
        $label = __("Shipping fee");
        $cost  = 9.00;
    }
*/
    echo json_encode($GLOBALS);

    //if ( isset($cost) )
        //$cart->add_fee( $label, $cost );
}

add_packaging_fee("test");

Answer 2

This is the modified code merged with yours, let me know if it works,

//Added this block
$packing_fees = array("gzeatp1" => "3.00", "box" => "9.00", "cotton" => "12.00");  //This is for testing purposes

$packing_fee = WC()->session->get( 'the_chosen_one' );  // make this a global variable

$callback =  
    function ($shipping_code, $packing_fee) use ($cost, &$packing_fees)
    {
        if($packing_fee === strtolower($shipping_code)) { 
           $label = __('Shipping fee');
           $cost = $packing_fees[$shipping_code];

           $GLOBALS["myfirstbowanstart"] = array("label" => $label, "cost"=> $cost);
        }
    };


 foreach($kekei as $good => $goodness) { 
   $callback($goodness['shipping_code'], $packing_fee) ;
 } 
/*  //Removed this block
 foreach($kekei as $good => $goodness) { 


                        ob_start();

                        $GLOBALS['myfirstbowanstart'] .= "if ( $packing_fee === 'strtolower(".$goodness['shipping_code'].")' ) {
                        $label = __('Shipping fee');
                        $cost  = ".$goodness['shipping_code'].";
                        }"; // put here your recursive function name

                        ob_get_clean();

                    }

*/

// Add a custom dynamic packaging fee
add_action( 'woocommerce_cart_calculate_fees', 'add_packaging_fee', 20, 1 );
function add_packaging_fee( $cart ) {
    if ( is_admin() && ! defined( 'DOING_AJAX' ) )
        return;

    //$domain      = "woocommerce";
    $packing_fee = WC()->session->get( 'the_chosen_one' ); // Dynamic packing fee

    //changed this line
    //echo $GLOBALS['myfirstbowanstart'];

    $label = $GLOBALS['myfirstbowanstart']['label'];
    $cost  = $GLOBALS['myfirstbowanstart']['cost'];

/*
    if ( $packing_fee === 'gzeatp1' ) {
        $label = __("Shipping fee");
        $cost  = 3.00;
    } elseif ( $packing_fee === 'box' ) {
        $label = __("Shipping fee");
        $cost  = 9.00;
    }
*/
    if ( isset($cost) )
        $cart->add_fee( $label, $cost );
}