How Swoole uses coroutines to implement multi-task concurrent downloads

With the increasing development of modern Internet, downloading tasks have become an indispensable part of people's lives. However, when downloading large files and multiple files, it is often necessary to use multi-task concurrent download technology to improve download speed and efficiency.

In traditional multi-task concurrent download implementation, multi-thread or multi-process technology is commonly used. However, in the case of high and large concurrency, the efficiency and performance of these technologies are often unsatisfactory, and there are also certain challenges to resource overhead and system stability.

Swoole is a multi-threaded, multi-process network Apache Foundation high-performance network communication framework that supports PHP language. Its powerful coroutine mechanism makes Swoole excellent in high concurrency and asynchronous task processing. Performance and Advantages. This article will introduce how to use Swoole coroutine to implement multi-task concurrent downloading.

1. Install Swoole extension

First, you need to install the Swoole extension, which can be installed through the command line:

$ pecl install swoole

It can also be installed in a PHP file Install by adding the extension command:

<?php
    dl('swoole.so');
?>

After the installation is completed, you can check whether the Swoole extension has been successfully installed through the phpinfo() function.

2. Implementing coroutine multi-task download

In order to implement coroutine multi-task download, you first need to determine the download source URL address and destination folder path. It is assumed here that the function get_urls() for obtaining the source URL address and the function get_download_folder() for obtaining the destination folder path have been implemented.

Next, you can use the coroutine mechanism provided by Swoole to achieve concurrent downloading of multiple tasks. The specific implementation method is as follows:

<?php
    //通过协程实现多任务下载
    go(function (){
        //获取URL地址
        $urls = get_urls();
        if(is_array($urls) && count($urls)>0){
            //获取目录路径
            $folder = get_download_folder();
            //循环下载
            foreach($urls as $url){
                $file_name = basename($url);
                //实现异步下载
                $client = new SwooleCoroutineHttpClient($url);
                $client->set(['timeout' => 10]);
                $client->download($folder . DIRECTORY_SEPARATOR . $file_name);
                //输出下载结果
                if($client->statusCode==200){
                    echo "$url 下载完成！".PHP_EOL;
                }else{
                    echo "$url 下载失败！".PHP_EOL;
                }
                //关闭连接
                $client->close();
            }
        }
    });
?>

In the above code, a go() function is implemented Coroutine, then obtain the URL address to be downloaded through the get_urls() function, and then obtain the directory path saved after downloading through the get_download_folder() function.

In the specific download operation, first obtain the file name through the basename() function, then download the file asynchronously through the coroutine client provided by Swoole, and set the downloaded file through $folder . DIRECTORY_SEPARATOR . $file_name The path to save.

During the download process, you can judge the download status through $client->statusCode. If the status is 200, it means the download is completed; if the status is not 200, it means the download failed. Finally, the connection is closed through the $client->close() command.

3. Achieving control of the number of concurrent multi-task downloads

In actual application, it is necessary to control the number of concurrent multi-task downloads to avoid excessive consumption of network resources caused by too many connections , leading to the emergence of network bottlenecks.

The following code is used to control the number of concurrent downloads of multiple tasks:

<?php
    //设置服务端异步任务并发数
    SwooleRuntime::enableCoroutine(true, SWOOLE_HOOK_ALL);
    SwooleCoroutine::set(['max_coroutine' => 1000]);
?>

In the above code, coroutine scheduling is enabled through the Runtime::enableCoroutine() function provided by Swoole, and then through Swoole The Coroutine::set() function is provided to set the concurrency number of asynchronous tasks. Here, the concurrency number is set to 1000.

4. Summary

Through Swoole's coroutine mechanism, the multi-task concurrent download function can be realized, which can better utilize the performance and advantages of server resources and improve download efficiency. And speed, it also has good advantages for processing large file download tasks.

In actual application, you need to pay attention to the control of the number of concurrent multi-task downloads, and reasonably allocate and schedule server resources and network traffic to avoid system bottlenecks and uncontrollable phenomena.

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