How to implement highly concurrent file downloads in Swoole

With the rapid development of the Internet and the advent of the big data era, high-concurrency applications are becoming more and more common, and file downloading is no exception. Implementing highly concurrent file downloads in Swoole has more advantages than traditional methods.

Swoole is a coroutine high-performance network communication engine in the PHP language. It can provide advanced features such as coroutines, asynchronous IO, and multi-process in PHP, and supports multiple protocols such as HTTP/WebSocket/TCP/UDP. Suitable for web development, game servers, Internet of Things, real-time communications and other fields. Next, we will use Swoole to achieve high-concurrency file downloading.

Step 1: Install the Swoole extension

First, we need to install the Swoole extension. You can install it according to the official documentation, or you can install it through Composer, the PHP package management tool. Here we install it through Composer.

Enter the following command in the terminal to install:

composer require swoole/swoole

Step 2: Write the code to download the file

Next, we start to write the code to download the file. We can download through the asynchronous HTTP client provided by Swoole.

$http = new SwooleCoroutineHttpClient('www.example.com', 80);
$http->setHeaders([
    'Host'            => 'www.example.com',
    'User-Agent'      => 'Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.71 Safari/537.36',
    'Accept'          => 'text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8',
    'Accept-Encoding' => 'gzip, deflate, sdch',
    'Accept-Language' => 'zh-CN,zh;q=0.8,en;q=0.6',
]);

$http->download('/path/to/localfile', '/remote/path/to/file');

In the above code, we instantiate an asynchronous HTTP client and set some parameters of the request, such as request header information, etc. Then call the download method to download the file. Among them, the first parameter is the local file path, and the second parameter is the remote path of the file to be downloaded.

Step 3: Encapsulate the code into a reusable method

The above code can only complete one file download. If a large number of downloads are required, the code needs to be encapsulated into a reusable method. In the method, we can use coroutines to implement multi-task concurrent download processing, as follows:

function batchDownload($uris, $outputDir, $concurrency = 64)
{
    $n = count($uris);
    $running = true;
    $workers = [];
    for ($i = 0; $i < $concurrency; $i++) {
        $co = run(function () use ($outputDir, &$running, &$workers) {
            $client = new SwooleCoroutineHttpClient('www.example.com', 80);
            while ($running || !empty($workers)) {
                if (!empty($workers)) {
                    $url = array_shift($workers);
                    $client->download("{$outputDir}/".basename($url), $url);
                } else {
                    Coroutine::sleep(0.1);
                }
            }
        });
        $workers[] = null;
    }
    foreach ($uris as $url) {
        $workers[] = $url;
    }
    $running = false;
    //所有协程结束后回收资源
    for ($i = 0; $i < $concurrency; $i++) {
        $co = array_shift($workers);
        $co->join();
    }
}

In the above code, we created $concurrency coroutines for asynchronous processing through a for loop. Each coroutine Each process is an independent request. After processing one request, it will automatically proceed to the next request, thereby achieving the purpose of processing multiple requests concurrently.

Similarly, the above code can download files in batches by calling the batchDownload method, as follows:

$uris = ['https://www.example.com/image1.jpg', 'https://www.example.com/image2.jpg', 'https://www.example.com/image3.jpg'];
$outputDir = '/path/to/output';
batchDownload($uris, $outputDir);

Summary

Implementing highly concurrent file downloads in Swoole is better than traditional methods Even better, asynchronous IO is implemented through coroutines, switching between CPU and IO without blocking and waiting for server response, which greatly improves the concurrent processing capabilities of requests. At the same time, it is convenient and fast to encapsulate the code into a reusable method, so that we can call it directly in subsequent development, improving development efficiency.

The above is the detailed content of How to implement highly concurrent file downloads in Swoole. For more information, please follow other related articles on the PHP Chinese website!