\Co\defer

###API

namespace Co;

function defer(Closure $closure): string;

Parameter description

Parameters	Type	Description
$closure	Closure	Delayed execution of the closure function, running in the event context

Closure parameters

none

Return value

Returns the unique identifier of the current event, allowing the event to be canceled using the \Co\cancel method

Overview

Defer (delayed execution), executes a closure function immediately after the current event ends, usually used for resource release and other operations.

Basic usage

\Co\async(function () {
    $file = fopen('file.txt', 'w');

    \Co\defer(function () use ($file) {
        //TODO: The code here will not be executed immediately
        fclose($file);
    });
    
    fwrite($file, 'hello world');
    return 'async task';
});

defer is useful in actual scenarios, such as releasing resources after an asynchronous request ends.

public function index(Request $request) : JsonResponse
{
    \Co\defer(function() use ($request){
        $response = \Co\await(
            \Co\Net::HTTP()->Guzzle()->getAsync('http://example.com');
        );
    
        $channel = \Co\IO::Channel()->open('websocket');
        $channel->send($response->getBody()->getContent());
        
        $channel->close();
    });
    
    return new JsonResponse(['status' => 'ok']);
}

hint

In the scaffolding provided by ripple, most framework controller requests will occur in the async space. You can use the \Co\defer method in the controller.