Asynchronous task management and execution in PHP

As a Web programming language, PHP plays an extremely important role in Web development. In real web applications, it is often necessary to perform some time-consuming tasks, such as processing large amounts of data, sending emails, etc. If these tasks are executed synchronously, it will bring a very long waiting time to the user and affect the user experience.

In order to solve this problem, PHP provides asynchronous task management and execution functions, which allows the PHP program to not be blocked when executing asynchronous tasks, but can continue to process other requests. This article will introduce the method of asynchronous task management and execution in PHP and its implementation principle.

1. Asynchronous task management

1. Commonly used asynchronous task management methods

(1) Multi-threading

Multi-threading is the implementation A common way of asynchronous tasks. In PHP, multi-threading can be easily implemented using the pthreads extension, for example:

class TestThreaded extends Threaded {
  public function run(){
    // 这里是执行的异步任务
  }
}

$test = new TestThreaded();
$test->start();

The TestThreaded class here inherits from the Threaded class and overrides the run() method, which implements asynchronous tasks. logic. By calling the start() method, the thread will be started and the asynchronous task will begin to execute.

(2) Message Queue

Message queue is also a commonly used asynchronous task management method. The message queues supported in PHP include Redis, RabbitMQ, etc. By adding tasks to the message queue, and then viewing the execution of asynchronous tasks through logs, emails, or other methods.

2. The implementation principle of asynchronous task management

Asynchronous task management mainly executes tasks by handing them over to other threads or processes, thus avoiding the main thread being blocked by the task. question. The implementation principle of multi-threading is that the operating system manages thread resources at the kernel level to prevent one thread from blocking other threads. The implementation principle of message queue is to add tasks to the queue and wait for other processes or threads to execute.

2. Asynchronous task execution

1. Commonly used asynchronous task execution methods

(1) Swoole

Swoole is a version of PHP The asynchronous network programming framework can realize asynchronous I/O, asynchronous tasks, multi-process and other functions, and has the characteristics of high performance and low consumption. By using Swoole on the server to provide asynchronous task services, the client can submit asynchronous tasks to the server through HTTP requests or other methods to achieve asynchronous execution.

(2) Curl Multi

Curl Multi is a PHP extension that supports processing multiple Curl requests at the same time. By using Curl Multi to implement asynchronous task execution, the concurrency capability of the program can be improved. For example:

$ch1 = curl_init();
curl_setopt($ch1, CURLOPT_URL, "http://www.example.com/");
curl_setopt($ch1, CURLOPT_RETURNTRANSFER, true);

$ch2 = curl_init();
curl_setopt($ch2, CURLOPT_URL, "http://www.example.org/");
curl_setopt($ch2, CURLOPT_RETURNTRANSFER, true);

$mh = curl_multi_init();
curl_multi_add_handle($mh,$ch1);
curl_multi_add_handle($mh,$ch2);

do {
    $status = curl_multi_exec($mh, $active);
    if ($active) {
        curl_multi_select($mh);
    }
} while ($active && $status == CURLM_OK);

curl_multi_remove_handle($mh, $ch1);
curl_multi_remove_handle($mh, $ch2);
curl_multi_close($mh);

Here two Curl requests are created, and then they are added to the Curl Multi execution queue through the curl_multi_add_handle() method. Finally, asynchronous execution is performed through the curl_multi_exec() method.

2. The implementation principle of asynchronous task execution

The characteristic of synchronous task execution is that the main thread will wait for the completion of task execution before continuing, while asynchronous task execution does not wait for the task. Finish. Swoole is asynchronous task execution through multi-threading and non-blocking I/O. Curl Multi is implemented through asynchronous Curl requests.

3. Summary

In actual Web applications, asynchronous task management and execution are very useful functions. It can improve the concurrency capability of the program, reduce response time, and improve user experience. PHP provides a variety of ways to implement asynchronous tasks, such as multi-threading, message queue, Swoole, Curl Multi, etc. Different implementation methods have their own advantages and disadvantages, and they should be chosen based on the business scenario.

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