PHP curl_multi_getcontent函数

示例 4：内容缓存与性能优化

@php
class CachedContentFetcher {
    private $multiHandle;
    private $cacheDir;
    private $cacheTtl;

    public function __construct($cacheDir = null, $cacheTtl = 3600) {
        $this->multiHandle = curl_multi_init();
        $this->cacheDir = $cacheDir ?: sys_get_temp_dir() . '/curl_cache';
        $this->cacheTtl = $cacheTtl;

        if (!is_dir($this->cacheDir)) {
            mkdir($this->cacheDir, 0755, true);
        }
    }

    public function fetchUrls($urls, $forceRefresh = false) {
        $results = [];
        $toFetch = [];

        echo "开始处理 " . count($urls) . " 个URL...\n";

        // 检查缓存
        foreach ($urls as $id => $url) {
            $cacheKey = $this->getCacheKey($url);
            $cacheFile = $this->cacheDir . '/' . $cacheKey;

            if (!$forceRefresh && $this->isCacheValid($cacheFile)) {
                // 使用缓存内容
                $cachedContent = file_get_contents($cacheFile);
                $cacheInfo = json_decode(file_get_contents($cacheFile . '.meta'), true);

                $results[$id] = [
                    'source' => 'cache',
                    'content' => $cachedContent,
                    'cached_at' => $cacheInfo['cached_at'],
                    'url' => $url
                ];

                echo "✓ {$id}: 使用缓存 (" . round(strlen($cachedContent) / 1024, 2) . " KB)\n";
            } else {
                // 需要重新获取
                $toFetch[$id] = $url;
            }
        }

        echo "缓存命中: " . (count($urls) - count($toFetch)) . "/" . count($urls) . "\n";

        // 获取未缓存的内容
        if (!empty($toFetch)) {
            $fetchResults = $this->fetchMultiple($toFetch);

            // 缓存新获取的内容
            foreach ($fetchResults as $id => $result) {
                if ($result['success']) {
                    $this->saveToCache($result['url'], $result['content']);
                    $result['source'] = 'network';
                }
                $results[$id] = $result;
            }
        }

        return $results;
    }

    private function fetchMultiple($urls) {
        $handles = [];
        $results = [];

        echo "开始并行获取 " . count($urls) . " 个URL...\n";

        // 创建并添加句柄
        foreach ($urls as $id => $url) {
            $handles[$id] = curl_init();
            curl_setopt_array($handles[$id], [
                CURLOPT_URL => $url,
                CURLOPT_RETURNTRANSFER => true,
                CURLOPT_TIMEOUT => 30,
                CURLOPT_FOLLOWLOCATION => true
            ]);
            curl_multi_add_handle($this->multiHandle, $handles[$id]);
        }

        // 执行并行请求
        $active = null;
        do {
            curl_multi_exec($this->multiHandle, $active);
            curl_multi_select($this->multiHandle, 0.1);
        } while ($active > 0);

        // 获取内容
        foreach ($handles as $id => $handle) {
            $content = curl_multi_getcontent($handle);
            $info = curl_getinfo($handle);
            $error = curl_error($handle);

            $results[$id] = [
                'success' => ($content !== false),
                'content' => $content,
                'url' => $urls[$id],
                'info' => $info,
                'error' => $error,
                'content_length' => strlen($content)
            ];

            curl_multi_remove_handle($this->multiHandle, $handle);
            curl_close($handle);

            $status = $results[$id]['success'] ? '成功' : '失败';
            echo "  {$id}: {$status} (" . round($info['total_time'], 2) . "秒)\n";
        }

        return $results;
    }

    private function getCacheKey($url) {
        return md5($url) . '.cache';
    }

    private function isCacheValid($cacheFile) {
        if (!file_exists($cacheFile) || !file_exists($cacheFile . '.meta')) {
            return false;
        }

        $cacheTime = filemtime($cacheFile);
        return (time() - $cacheTime) < $this->cacheTtl;
    }

    private function saveToCache($url, $content) {
        $cacheKey = $this->getCacheKey($url);
        $cacheFile = $this->cacheDir . '/' . $cacheKey;

        // 保存内容
        file_put_contents($cacheFile, $content);

        // 保存元数据
        $meta = [
            'url' => $url,
            'cached_at' => time(),
            'content_length' => strlen($content),
            'content_type' => 'unknown' // 在实际应用中可以从curl信息获取
        ];
        file_put_contents($cacheFile . '.meta', json_encode($meta));
    }

    public function clearCache($olderThan = null) {
        $files = glob($this->cacheDir . '/*.cache');
        $cleared = 0;

        foreach ($files as $file) {
            if ($olderThan === null || (time() - filemtime($file)) > $olderThan) {
                unlink($file);
                unlink($file . '.meta'); // 同时删除元数据文件
                $cleared++;
            }
        }

        return $cleared;
    }

    public function getCacheStats() {
        $files = glob($this->cacheDir . '/*.cache');
        $totalSize = 0;

        foreach ($files as $file) {
            $totalSize += filesize($file);
        }

        return [
            'file_count' => count($files),
            'total_size' => $totalSize,
            'total_size_mb' => round($totalSize / 1024 / 1024, 2)
        ];
    }

    public function close() {
        if (is_resource($this->multiHandle)) {
            curl_multi_close($this->multiHandle);
        }
    }

    public function __destruct() {
        $this->close();
    }
}

// 使用缓存内容获取器
$cacheDir = sys_get_temp_dir() . '/demo_curl_cache';
$fetcher = new CachedContentFetcher($cacheDir, 300); // 5分钟缓存

// 要获取的URL列表
$urls = [
    'api1' => 'https://httpbin.org/json',
    'api2' => 'https://httpbin.org/xml',
    'api3' => 'https://httpbin.org/uuid',
    'api4' => 'https://httpbin.org/headers'
];

echo "=== 第一次获取（将缓存内容）===\n";
$results1 = $fetcher->fetchUrls($urls);

echo "\n=== 第二次获取（应使用缓存）===\n";
$results2 = $fetcher->fetchUrls($urls);

// 显示缓存统计
$stats = $fetcher->getCacheStats();
echo "\n缓存统计:\n";
echo "缓存文件数: " . $stats['file_count'] . "\n";
echo "缓存总大小: " . $stats['total_size_mb'] . " MB\n";

// 显示结果来源统计
$sourceCounts = ['cache' => 0, 'network' => 0];
foreach ($results2 as $result) {
    $sourceCounts[$result['source']]++;
}

echo "\n第二次获取来源:\n";
echo "缓存: {$sourceCounts['cache']}\n";
echo "网络: {$sourceCounts['network']}\n";

// 清理缓存示例
// $cleared = $fetcher->clearCache(60); // 清理1分钟前的缓存
// echo "清理了 {$cleared} 个缓存文件\n";

$fetcher->close();
@endphp