告别漫长等待：如何使用Composer与GuzzlePromises优雅处理PHP异步操作

<code class="bash">composer require guzzlehttp/promises</code>

<pre class="brush:php;toolbar:false;"><?php

require 'vendor/autoload.php';

use GuzzleHttp\Promise\Promise;

// 模拟一个异步操作，比如从API获取数据
function fetchDataAsync(string $name, int $delay): Promise
{
    $promise = new Promise(function () use (&$promise, $name, $delay) {
        // 模拟耗时操作
        sleep($delay);
        // 随机决定成功或失败
        if (rand(0, 1)) {
            $promise->resolve("Hello, {$name}!");
        } else {
            $promise->reject(new Exception("Failed to fetch data for {$name}."));
        }
    });
    return $promise;
}

echo "开始异步操作...\n";

// 创建两个异步操作的Promise
$promise1 = fetchDataAsync('Alice', 2);
$promise2 = fetchDataAsync('Bob', 1);

// 使用 then() 方法注册成功和失败的回调
$promise1->then(
    function ($value) {
        echo "Promise 1 成功: " . $value . "\n";
    },
    function (Throwable $reason) {
        echo "Promise 1 失败: " . $reason->getMessage() . "\n";
    }
);

$promise2->then(
    function ($value) {
        echo "Promise 2 成功: " . $value . "\n";
    },
    function (Throwable $reason) {
        echo "Promise 2 失败: " . $reason->getMessage() . "\n";
    }
);

// 如果需要等待所有Promise完成并获取结果，可以使用 Promise::all() (GuzzleHttp\Promise\Utils::all)
// 或者在单个 Promise 上使用 wait() 方法
echo "等待所有Promise完成...\n";

try {
    // 强制等待 promise1 完成并获取结果 (会阻塞当前进程)
    $result1 = $promise1->wait();
    echo "Promise 1 最终结果 (wait): " . $result1 . "\n";
} catch (Throwable $e) {
    echo "Promise 1 最终失败 (wait): " . $e->getMessage() . "\n";
}

try {
    // 强制等待 promise2 完成并获取结果
    $result2 = $promise2->wait();
    echo "Promise 2 最终结果 (wait): " . $result2 . "\n";
} catch (Throwable $e) {
    echo "Promise 2 最终失败 (wait): " . $e->getMessage() . "\n";
}

echo "所有操作完成。\n";