PHP 常用工具函數庫：文件讀寫、靜態生成、分頁、上傳、目錄操作、驗證

文件讀寫

function readFile(string $path): string|false {
    if (!is_file($path)) return false;
    return file_get_contents($path); // PHP 4.3+ 內建，比 fopen/fread 簡潔
}
function writeFile(string $path, string $data, bool $lock = true): int|false {
    $flags = $lock ? LOCK_EX : 0;
    return file_put_contents($path, $data, $flags);
}

靜態頁生成

function generateStatic(string $sourceUrl, string $destPath, array $vars = []): bool {
    ob_start();
    extract($vars);
    include $sourceUrl; // 模板文件中直接使用變量
    $html = ob_get_clean();
    return writeFile($destPath, $html) !== false;
}

分頁類（PDO 版）

class Paginator {
    public function __construct(
        private PDO $pdo,
        private string $table,
        private string $where = '',
        private array $params = [],
        private int $perPage = 20
    ) {}
    public function getTotal(): int {
        $sql = "SELECT COUNT(*) FROM {$this->table} {$this->where}";
        return (int)$this->pdo->prepare($sql)->execute($this->params)->fetchColumn();
    }
    public function getPage(int $page): array {
        $offset = ($page - 1) * $this->perPage;
        $sql = "SELECT * FROM {$this->table} {$this->where} LIMIT {$offset}, {$this->perPage}";
        return $this->pdo->prepare($sql)->execute($this->params)->fetchAll();
    }
    public function getLinks(int $page, int $display = 5): string {
        $total = $this->getTotal();
        $pages = ceil($total / $this->perPage);
        if ($pages <= 1) return '';
        $html = '';
        return $html;
    }
}

圖片上傳（安全版）

function uploadImage(array $file, string $destDir, array $allowExt = ['jpg','jpeg','png','gif','webp'], int $maxSize = 2*1024*1024): array {
    // 1. 錯誤碼檢查
    if ($file['error'] !== UPLOAD_ERR_OK) return ['ok'=>false, 'msg'=>'上傳錯誤碼:'.$file['error']];
    // 2. 大小
    if ($file['size'] > $maxSize) return ['ok'=>false, 'msg'=>'文件過大'];
    // 3. 擴展名 + MIME 雙重驗證
    $ext = strtolower(pathinfo($file['name'], PATHINFO_EXTENSION));
    if (!in_array($ext, $allowExt)) return ['ok'=>false, 'msg'=>'禁止的格式'];
    $finfo = new finfo(FILEINFO_MIME_TYPE);
    $mime = $finfo->file($file['tmp_name']);
    if (!in_array($mime, ['image/jpeg','image/png','image/gif','image/webp'])) return ['ok'=>false, 'msg'=>'MIME 不匹配'];
    // 4. 隨機文件名防衝突/遍歷
    $newName = bin2hex(random_bytes(16)) . ".{$ext}";
    $destPath = rtrim($destDir, '/') . '/' . $newName;
    if (!move_uploaded_file($file['tmp_name'], $destPath)) return ['ok'=>false, 'msg'=>'移動失敗'];
    // 5. 可選：二次渲染去除 EXIF/腳本
    // $img = imagecreatefromstring(file_get_contents($destPath)); imagejpeg($img, $destPath);
    return ['ok'=>true, 'path'=>$destPath, 'url'=>'/uploads/'.$newName, 'size'=>$file['size']];
}

目錄遞歸刪除

function deleteDir(string $dir): bool {
    if (!is_dir($dir)) return false;
    $items = new RecursiveIteratorIterator(
        new RecursiveDirectoryIterator($dir, FilesystemIterator::SKIP_DOTS),
        RecursiveIteratorIterator::CHILD_FIRST
    );
    foreach ($items as $item) {
        $item->isDir() ? rmdir($item->getPathname()) : unlink($item->getPathname());
    }
    return rmdir($dir);
}

常用驗證正則

IP 合法性快速判斷

function isValidIp(string $ip): bool {
    return filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4 | FILTER_FLAG_IPV6) !== false;
}
// CIDR 範圍檢查
function ipInCidr(string $ip, string $cidr): bool {
    [$range, $bits] = explode('/', $cidr);
    $mask = ~((1 << (32 - $bits)) - 1);
    return (ip2long($ip) & $mask) === (ip2long($range) & $mask);
}

文件下載響應頭

function downloadHeaders(string $filename, int $size, string $mime = 'application/octet-stream'): void {
    header('Content-Type: ' . $mime);
    header('Content-Disposition: attachment; filename="' . rawurlencode($filename) . '"');
    header('Content-Length: ' . $size);
    header('Accept-Ranges: bytes');
    header('Cache-Control: private, must-revalidate');
    header('Pragma: public');
}