仅在PHP中上载某些文件(运行Docker for Windows)

<?php
if ($_FILES["file"]["error"] > 0) {
    echo "文件上传错误：" . $_FILES["file"]["error"];
} else {
    $allowedExtensions = array("jpg", "jpeg", "png", "gif");
    $maxFileSize = 5 * 1024 * 1024; // 5MB

    $fileName = $_FILES["file"]["name"];
    $fileExtension = strtolower(pathinfo($fileName, PATHINFO_EXTENSION));

    if (!in_array($fileExtension, $allowedExtensions)) {
        echo "只允许上传以下文件类型：" . implode(", ", $allowedExtensions);
    } elseif ($_FILES["file"]["size"] > $maxFileSize) {
        echo "文件大小超过限制：" . $maxFileSize / (1024 * 1024) . "MB";
    } else {
        $uploadPath = "uploads/" . $fileName;
        move_uploaded_file($_FILES["file"]["tmp_name"], $uploadPath);
        echo "文件上传成功！";
    }
}
?>