Support for closures

[Iacovos Constantinou]

The documentation does not mention anything about closures but it appears that those are supported by InMemoryQueue. Please consider the following scenario:

$queue = new InMemoryQueue();
$queue->push(function() { 
    return 'Example with closures'; 
});
$item = $queue->pop();
echo $item();

The above scenario is executed successfully, printing "Example with closures". Some other Queue Types may not support this directly, but we can serialise closures using jeremeamia/SuperClosure library.

Are there any plans to support closures?

[Eugene Leonovich]

Closures are supported in InMemoryQueue only because it's not a persistent queue. For any other queue you indeed have to serialize closure before inserting. So you can do something like this:

// if the queue does not support object types, 
// wrap it with TypeSafeQueue decorator:
// $queue = new TypeSafeQueue($queue);

$item = new SerializableClosure(function() {
    return 'Example with closures';
});

$queue->push($item);

It's also quite trivial to create a decorator which will wrap closures automatically:

class SuperTypeSafeQueue extends TypeSafeQueue
{
    public function push($item, $eta = null)
    {
        if ($item instanceof \Closure) {
            $item = new SerializableClosure($item);
        }

        parent::push($item, $eta);
    }
}

Now you can pass them directly, just like in your example:

$queue = new SuperTypeSafeQueue($queue);

$queue->push(function() { 
    return 'Example with closures'; 
});

[Eugene Leonovich]

Closing this, as I don't think it worth adding extra dependencies to the library for such a simple use case. Moreover, the solution is really trivial to implement for ones who still need to pass closures directly.