Cache.class.php

<?php
/**
 * 缓存管理类
 * 支持文件缓存，具备缓存键生成、过期控制等功能
 */
class Cache {
    private static $cacheDir;
    private static $defaultTTL = 300;

    private static function init() {
        if (self::$cacheDir === null) {
            if (defined('CACHE_DIR')) {
                self::$cacheDir = CACHE_DIR;
            } else {
                self::$cacheDir = __DIR__ . '/cache';
            }
            if (!is_dir(self::$cacheDir)) {
                @mkdir(self::$cacheDir, 0755, true);
            }
        }
    }

    public static function setCacheDir($dir) {
        self::$cacheDir = rtrim($dir, '/\\');
        self::init();
    }

    public static function setDefaultTTL($seconds) {
        self::$defaultTTL = (int)$seconds;
    }

    public static function getCacheKey($prefix, $params = []) {
        $parts = [$prefix];
        foreach ($params as $key => $value) {
            if (is_array($value) || is_object($value)) {
                $value = json_encode($value, JSON_UNESCAPED_UNICODE);
            }
            $parts[] = $key . '_' . md5((string)$value);
        }
        return implode('_', $parts);
    }

    public static function get($key, $default = null) {
        self::init();
        $file = self::getCacheFile($key);
        
        if (!file_exists($file)) {
            return $default;
        }

        $content = file_get_contents($file);
        if ($content === false) {
            return $default;
        }

        $data = @unserialize($content, ['allowed_classes' => false]);
        if ($data === false) {
            @unlink($file);
            return $default;
        }

        if (!isset($data['expires']) || !isset($data['value'])) {
            @unlink($file);
            return $default;
        }

        if ($data['expires'] > 0 && $data['expires'] < time()) {
            @unlink($file);
            return $default;
        }

        return $data['value'];
    }

    public static function set($key, $value, $ttl = null) {
        self::init();
        $file = self::getCacheFile($key);
        
        $dir = dirname($file);
        if (!is_dir($dir)) {
            @mkdir($dir, 0755, true);
        }

        $ttl = $ttl !== null ? (int)$ttl : self::$defaultTTL;
        $expires = $ttl > 0 ? time() + $ttl : 0;

        $data = [
            'expires' => $expires,
            'value' => $value
        ];

        return @file_put_contents($file, serialize($data), LOCK_EX) !== false;
    }

    public static function delete($key) {
        self::init();
        $file = self::getCacheFile($key);
        return file_exists($file) && @unlink($file);
    }

    public static function clear($prefix = null) {
        self::init();
        $result = true;
        
        if ($prefix === null) {
            $files = glob(self::$cacheDir . '/*');
            foreach ($files as $file) {
                if (is_file($file)) {
                    $result = $result && @unlink($file);
                }
            }
        } else {
            $files = glob(self::$cacheDir . '/' . $prefix . '_*.cache');
            foreach ($files as $file) {
                if (is_file($file)) {
                    $result = $result && @unlink($file);
                }
            }
        }
        
        return $result;
    }

    public static function exists($key) {
        self::init();
        $file = self::getCacheFile($key);
        
        if (!file_exists($file)) {
            return false;
        }

        $content = @file_get_contents($file);
        if ($content === false) {
            return false;
        }

        $data = @unserialize($content, ['allowed_classes' => false]);
        if ($data === false || !isset($data['expires'])) {
            return false;
        }

        if ($data['expires'] > 0 && $data['expires'] < time()) {
            @unlink($file);
            return false;
        }

        return true;
    }

    public static function remember($key, $ttl, $callback) {
        $value = self::get($key);
        if ($value !== null) {
            return $value;
        }

        $value = $callback();
        self::set($key, $value, $ttl);
        return $value;
    }

    private static function getCacheFile($key) {
        $safeKey = preg_replace('/[^a-zA-Z0-9_-]/', '_', $key);
        return self::$cacheDir . '/' . $safeKey . '.cache';
    }

    public static function gc($maxLifetime = 86400) {
        self::init();
        $files = glob(self::$cacheDir . '/*.cache');
        $now = time();
        $deleted = 0;

        foreach ($files as $file) {
            if (is_file($file)) {
                $mtime = filemtime($file);
                if ($now - $mtime > $maxLifetime) {
                    @unlink($file);
                    $deleted++;
                }
            }
        }

        return $deleted;
    }
}

/**
 * 简单的缓存辅助函数
 */
function cache_get($key, $default = null) {
    return Cache::get($key, $default);
}

function cache_set($key, $value, $ttl = null) {
    return Cache::set($key, $value, $ttl);
}

function cache_delete($key) {
    return Cache::delete($key);
}

function cache_clear($prefix = null) {
    return Cache::clear($prefix);
}

function cache_remember($key, $ttl, $callback) {
    return Cache::remember($key, $ttl, $callback);
}