\Co\async

###API

namespace Co;

function async(Closure $closure): Promise;

Parameter description

Parameters	Type	Description
$closure	Closure	Entry closure function, immediately runs in the coroutine context

Closure parameters

Parameters	Type	Description
$resolve	Closure	Resolve contract
$reject	Closure	Reject future contract

Overview

Async (asynchronous operation) is one of the core concepts of coroutines implemented in the ripple framework. It manages state based on the Promise mechanism and expands the asynchronous operation capabilities of coroutines.

Usage

Use this method to create a Promise object

$promise = \Co\async(Closure $callback): Promise

Ripple will also provide two parameters for the submitted closure function, one is the resolve callback function and the other is the reject callback function. Use these two callback functions to resolve or reject a promise. Unlike the promise method, async supports more asynchronous operations. And using the async method usually does not require explicit processing of resolve and reject, it will automatically resolve the deadline during the running process,

Example

\Co\async(function () {
    \Co\sleep(1);
    
    echo 'async task 1';
});

\Co\async(function () {
    \Co\sleep(1);
    
    echo 'async task 2';
});

\Co\async(function () {
    \Co\sleep(1);
    
    echo 'async task 3';
});

In the above example, the code in async will be executed immediately, and when encountering \Co\sleep, the current coroutine will be automatically suspended, and the processor will execute other coroutines during the suspension period. Until the suspended coroutine is awakened. without blocking the execution of other coroutines.

Automatically resolve appointments

Normally, the async method will automatically resolve the contract

• When an exception occurs within the closure, the contract will be automatically rejected
• When a return value occurs within the closure, the contract will be automatically resolved
• When the closure completes normal execution, the expiration date (null) will be automatically resolved

$promise = \Co\async(function () {
    \Co\sleep(1);
    
    if(rand(0,1) === 1){
        throw new Exception('error');
    }
    return 'success';
});

NOTE: In some cases, you may need to manually resolve the expiration date

$promise = \Co\async(function ($resolve, $reject) {
    \Co\sleep(1);
    
    if(rand(0,1) === 1){
        $reject(new Exception('error'));
    }
    $resolve('success');
    
    // The code here will be executed, but will not affect the status of the contract.
    return 'done';
});

Await

The implementation of sleep is the best example of coroutine, but in actual development, we may need to deal with more scenarios, such as

function httpGet(string $url) : Promise {
    return \Co\Net::Http()->Gullze()->getAsync($url);
}

\Co\async(function(){
    $response = \Co\await(httpGet('http://example.com'));
    
    echo $response->getBody()->getContent();
});

Notes

await can only be used in async, and can only wait for Promise objects. Outside the closure you can do this:

function httpGet(string $url) : Promise {
   return \Co\Net::Http()->Gullze()->getAsync($url);
}


httpGet('http://example.com')->then(function($response){
    echo $response->getBody()->getContent();
});

hint

In the scaffolding provided by ripple, most framework controller requests will occur in the async space. You can use the async method in the controller to handle asynchronous operations.