从文件名中删除特殊字符

我正在建立一个可供人们上传图像的网站。但是，当最终用户上载包含特殊字符或外来字符的图像时，该图像确实会上载，但无法在网站上显示，就像服务器上不存在该图像一样。

我看到很多人在另一个帖子上回答说我需要使用 preg_replace

但问题是，我真的不知道如何使用它。我将如何在代码中使用它。

这是我的控制器方法：

public function upload(Requests\CreatePostsRequest $request)
{
        $target_dir = "uploads/";
        $target_file = $target_dir . basename($_FILES['fileToUpload']["name"]);
        $uploadOk = 1;
        $findme   = ".";
        $pos = strpos($target_file, $findme);
        //echo $target_file;
        //dd($_POST);
        echo ini_get('upload_max_filesize');
        echo $_FILES["fileToUpload"]["error"];
        $imageFileType = strtolower(substr($target_file,$pos+1));
        if(isset($_POST["submit"])) {
            $check = getimagesize($_FILES["fileToUpload"]["tmp_name"]);
                //$check = true;
                //dd($check);
            if($check !== false) {
                echo "File is an image - " . $check["mime"] . ".";
                $uploadOk = 1;
            } else {
                echo "File is not an image.";
                $uploadOk = 0;
            }
        }
        $filecheck = 0;
        $orgFileName = $target_file;
        while (file_exists($target_file)) {
            $target_file = substr($orgFileName,0,$pos).$filecheck.substr($orgFileName,$pos);
            $filecheck++;

            $uploadOk = 1;
        }

        if ($_FILES["fileToUpload"]["size"] > 500000000*8) {
            echo "Sorry, your file is too large.";
            $uploadOk = 0;
        }

        if($imageFileType != "jpg" && $imageFileType != "png" && $imageFileType != "jpeg"
        && $imageFileType != "gif" ) {
            echo "Sorry, only JPG, JPEG, PNG & GIF files are allowed.";
                echo $imageFileType;
            $uploadOk = 0;
        }

        if ($uploadOk == 0) {
            echo "Sorry, your file was not uploaded.";

        } else {
            if (move_uploaded_file($_FILES["fileToUpload"]["tmp_name"], $target_file)) {
                echo "The file ". basename( $_FILES["fileToUpload"]["name"]). " has been uploaded.";

                        $post = new Posts($request->all());
                        $post->fileToUpload = $target_file;
                        Auth::user()->posts()->save($post);
            } else {
                echo "Sorry, there was an error uploading your file.";
            }
        }
        return redirect('');
        echo $target_file;
    }