PHP - 重命名文件以禁止重复

Question

所以我使用这个脚本将文件上传到目录并实时显示。

<?php
    function UploadImage($settings = false)
        {
            // Input allows you to change where your file is coming from so you can port this code easily
            $inputname      =   (isset($settings['input']) && !empty($settings['input']))? $settings['input'] : "fileToUpload";
            // Sets your document root for easy uploading reference
            $root_dir       =   (isset($settings['root']) && !empty($settings['root']))? $settings['root'] : $_SERVER['DOCUMENT_ROOT'];
            // Allows you to set a folder where your file will be dropped, good for porting elsewhere
            $target_dir     =   (isset($settings['dir']) && !empty($settings['dir']))? $settings['dir'] : "/uploads/";
            // Check the file is not empty (if you want to change the name of the file are uploading)
            if(isset($settings['filename']) && !empty($settings['filename']))
                $filename   =   $settings['filename'] . "sss";
            // Use the default upload name
            else
                $filename   =   preg_replace('/[^a-zA-Z0-9._-]/',"",$_FILES[$inputname]["name"]);
            // If empty name, just return false and end the process
            if(empty($filename))
                return false;
            // Check if the upload spot is a real folder
            if(!is_dir($root_dir.$target_dir))
                // If not, create the folder recursively
                mkdir($root_dir.$target_dir,0755,true);
            // Create a root-based upload path
            $target_file    =   $root_dir.$target_dir.$filename;
            // If the file is uploaded successfully...
            if(move_uploaded_file($_FILES[$inputname]["tmp_name"],$target_file)) {
                    // Save out all the stats of the upload
                    $stats['filename']  =   $filename;
                    $stats['fullpath']  =   $target_file;
                    $stats['localpath'] =   $target_dir.$filename;
                    $stats['filesize']  =   filesize($target_file);
                    // Return the stats
                    return $stats;
                }
            // Return false
            return false;
        }
?>
<?php
    // Make sure the above function is included...
    // Check file is uploaded
    if(isset($_FILES["fileToUpload"]["name"]) && !empty($_FILES["fileToUpload"]["name"])) {
        // Process and return results
        $file   =   UploadImage();
        // If success, show image
        if($file != false) { ?>
            <img src="<?php echo $file['localpath']; ?>" />
        <?php
            }
    }
?>

我担心的是，如果一个人上传了一个与另一个人同名的文件，它会覆盖它。我将如何从url中抓取文件名，并添加一个随机字符串来代替文件名。

说明：当有人上传图片时，它当前显示为

www.example.com/%filename%.png。

我希望它显示为

www.example.com/randomstring.png

使图像几乎不可能相互覆盖。

谢谢你的帮助，一个php菜鸟

Answer 1

正如评论中的贡献，我在文件名的末尾添加了一个时间戳，如下所示：

if(isset($settings['filename']) && !empty($settings['filename']))
                $filename   =   $settings['filename'] . "sss";
            // Use the default upload name
            else
                $filename   =   preg_replace('/[^a-zA-Z0-9._-]/',"",$_FILES[$inputname]["name"]) . date('YmdHis');

谢谢你的帮助