Laravel: Using external variable after processing data?

Question

I have a function getUnfilledOrders where I get Orders from the database and then use chunk to have them go to checkStatus 10 at a time. If I have 100 orders, the flow I believe would happen is checkStatus get will get called 10 times (since there are 100 orders).
Now once that completes, I want to have access to $totalOrders in getUnfulfilledOrders. Is this possible?

protected function getUnfulfilledOrders()
{
    Order::where('order_status', '!=', true)
        ->where('tracking_number', '!=', null)
        ->limit(3000)
        ->chunk(10, function ($unfulfilledOrders) {
            $this->checkStatus($unfulfilledOrders);
        });

   // how to do something now with $totalOrders once ALL Orders are processed 10 at a time;

}

protected function checkStatus($unfilledOrders)
{
    $totalOrders = array();

    foreach ($unfulfilledOrders as $unfulfilledOrder) {
         // logic here
         array_push($totalOrders, $unfulFilledOrder->id);
    }
}

DevK · Accepted Answer · 2020-01-26 06:42:18Z

1

Like this:

protected function getUnfulfilledOrders()
{
    $totalOrders = [];

    Order::where('order_status', '!=', true)
        ->where('tracking_number', '!=', null)
        ->limit(3000)
        // Add use (&$totalOrders)
        ->chunk(10, function ($unfulfilledOrders) use (&$totalOrders) {
            $totalOrders = array_merge($totalOrders, $this->checkStatus($unfulfilledOrders));
        });

   // how to do something now with $totalOrders once ALL Orders are processed 10 at a time;

}

protected function checkStatus($unfilledOrders)
{
    $totalOrders = array();

    foreach ($unfulfilledOrders as $unfulfilledOrder) {
         // logic here
         array_push($totalOrders, $unfilledOrder->id);
    }

    // Return the generated array
    return $totalOrders;
}

Here I initiated an empty array at the start of getUnfulfilledOrders() and merged anything returned by checkStatus() into it.

3 Comments

burtonLowel Over a year ago

ah smart approach, thanks! What does // Add use (&$totalOrders) mean? I will definitely use this approach but just curious if another way to do it would be by creating a global variable? I come from a JS background but I assume PHP has this?

DevK Over a year ago

The callbacks in PHP don't have access to outside variables by itself. You need to add use ($var) in order to be able to access a var from outside scope. But by default use ($var) passes in a "copy" of the variable, so doing anything with it wouldn't have an effect on the variable outside of the callback. Prefixing it with & however, passes the variable by reference so that any changes made within the callback will change the variable outside of the callback as well.

burtonLowel Over a year ago

great explanation , Thanks!!

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