PHP实现简易文件服务器：目录浏览与文件下载教程

<?php
    $filesInFolder = array();
    $directory = "src"; // 假设这是我们要展示的目录
    $iterator = new FilesystemIterator($directory);

    foreach($iterator as $entry){
        $filesInFolder[] = $entry->getFilename();
    }

    foreach($filesInFolder as $file){
        echo "<a href='/$file'> $file </a>";
    }
?>

<?php
$baseDir = "/var/www/html/test"; // 定义文件服务器的根目录，防止访问敏感区域
$currentDir = !empty($_GET['dir']) ? $_GET['dir'] : $baseDir;
$currentDir = rtrim($currentDir, '/'); // 确保路径末尾没有斜杠，方便拼接

// 安全性检查：确保请求的目录在baseDir内部
if (strpos($currentDir, $baseDir) !== 0) {
    $currentDir = $baseDir; // 如果路径越界，则强制回到根目录
}
?>

<?php
if (isset($_GET['download'])) {
    $filePath = $_GET['download'];

    // 安全性检查：确保下载的文件在baseDir内部
    if (strpos($filePath, $baseDir) !== 0 || !is_file($filePath)) {
        header("HTTP/1.0 403 Forbidden");
        exit("Access Denied or File Not Found.");
    }

    // 设置HTTP头，强制浏览器下载文件
    header('Content-Description: File Transfer');
    header('Content-Type: application/octet-stream');
    header('Content-Disposition: attachment; filename="' . basename($filePath) . '"');
    header('Expires: 0');
    header('Cache-Control: must-revalidate');
    header('Pragma: public');
    header('Content-Length: ' . filesize($filePath));
    readfile($filePath);
    exit;
}
?>

<?php
// ... (之前的baseDir, currentDir, download逻辑) ...

// 检查currentDir是否存在且是目录
if (!is_dir($currentDir)) {
    exit("Error: Directory not found or is not a directory.");
}

$iterator = new FilesystemIterator($currentDir);
echo "<h3>当前目录: " . htmlspecialchars($iterator->getPath()) . "</h3>";

// 添加返回上一级目录的链接
if ($currentDir !== $baseDir) {
    $parentDir = dirname($currentDir);
    echo "D: <a href='?dir=" . htmlspecialchars($parentDir) . "'>.. (上级目录)</a><br />";
}

foreach ($iterator as $entry) {
    $name = $entry->getBasename();
    $fullPath = $currentDir . '/' . $name;

    if (is_dir($fullPath)) {
        // 如果是目录，生成一个链接，点击后将dir参数设为该目录的路径
        echo "D: <a href='?dir=" . htmlspecialchars($fullPath) . "'>" . htmlspecialchars($name) . "</a><br />";
    } elseif (is_file($fullPath)) {
        // 如果是文件，生成一个链接，点击后将download参数设为该文件的路径，并添加download属性触发下载
        echo "F: <a href='?download=" . htmlspecialchars($fullPath) . "' download='" . htmlspecialchars($name) . "'> " . htmlspecialchars($name) . " </a><br />";
    }
}
?>

<?php
// 定义文件服务器的根目录，必须是服务器上的绝对路径
// 例如：/var/www/html/my_fileserver_root
$baseDir = "/var/www/html/test_files"; // 请根据您的实际情况修改此路径

// --- 安全性检查辅助函数 ---
function isValidPath($path, $base) {
    // 确保路径是绝对路径
    if (strpos($path, '/') !== 0) {
        return false;
    }
    // 确保路径在基目录内
    $realBasePath = realpath($base);
    $realPath = realpath($path);
    if ($realPath === false || strpos($realPath, $realBasePath) !== 0) {
        return false;
    }
    return true;
}

// --- 处理文件下载请求 ---
if (isset($_GET['download'])) {
    $filePath = $_GET['download'];

    // 严格检查下载路径的安全性
    if (!isValidPath($filePath, $baseDir) || !is_file($filePath)) {
        header("HTTP/1.0 403 Forbidden");
        exit("访问被拒绝或文件未找到。");
    }

    // 设置HTTP头，强制浏览器下载文件
    header('Content-Description: File Transfer');
    header('Content-Type: application/octet-stream');
    header('Content-Disposition: attachment; filename="' . basename($filePath) . '"');
    header('Expires: 0');
    header('Cache-Control: must-revalidate');
    header('Pragma: public');
    header('Content-Length: ' . filesize($filePath));
    readfile($filePath);
    exit;
}

// --- 处理目录浏览请求 ---
$currentDir = !empty($_GET['dir']) ? $_GET['dir'] : $baseDir;
$currentDir = rtrim($currentDir, '/'); // 移除路径末尾的斜杠

// 严格检查当前目录路径的安全性
if (!isValidPath($currentDir, $baseDir) || !is_dir($currentDir)) {
    $currentDir = $baseDir; // 如果路径无效或不是目录，则强制回到根目录
}

echo "<h3>当前目录: " . htmlspecialchars(str_replace($baseDir, '', $currentDir)) . "</h3>"; // 显示相对路径

// 添加返回上一级目录的链接
if ($currentDir !== $baseDir) {
    $parentDir = dirname($currentDir);
    echo "D: <a href='?dir=" . htmlspecialchars($parentDir) . "'>.. (上级目录)</a><br />";
}

// 遍历当前目录内容
try {
    $iterator = new FilesystemIterator($currentDir);
    foreach ($iterator as $entry) {
        $name = $entry->getBasename();
        $fullPath = $currentDir . '/' . $name;

        if (is_dir($fullPath)) {
            echo "D: <a href='?dir=" . htmlspecialchars($fullPath) . "'>" . htmlspecialchars($name) . "</a><br />";
        } elseif (is_file($fullPath)) {
            echo "F: <a href='?download=" . htmlspecialchars($fullPath) . "' download='" . htmlspecialchars($name) . "'> " . htmlspecialchars($name) . " </a><br />";
        }
    }
} catch (UnexpectedValueException $e) {
    echo "Error: 无法读取目录内容。";
}
?>