PHP - Random file name when upload a file into directory and add to the bottom the file extension?

Question

I made a uload sistem using php and html, and java, but i am worried about the duplipicate files. How can I made it to save with a random name and add its extension?

<?php
   if(isset($_FILES['image'])){
      $errors= array();
      $test = uniqid()
      $file_name = ['image']['name'];
      $file_size =$_FILES['image']['size'];
      $file_tmp =$_FILES['image']['tmp_name'];
      $file_type=$_FILES['image']['type'];
      $file_ext=strtolower(end(explode('.',$_FILES['image']['name'])));
      
      $extensions= array("jpeg","jpg","png","rbxl","mp4","mp3");
      
      if(in_array($file_ext,$extensions)=== false){
         $errors[]="extension not allowed";
      }
      
      if($file_size > 600000000){
         $errors[]='File size must be excately 600 MB';
      }
      
      if(empty($errors)==true){
         move_uploaded_file($file_tmp,"images/".$file_name);
         echo "https://glotech.cf/images/";
         print_r($file_name);
      }else{
         print_r($errors);
      }
        
   }
?>   

 window.addEventListener("paste", e => { if (e.clipboardData.files.length > 0) { const fileImput = document.querySelector("#myFile"); fileImput.files = e.clipboardData.files; } });

 <form action="/test.php" method="post" enctype="multipart/form-data"> <input type="file" name="image" id="myFile"> <input type="submit" /> </form>

How can I made it to save it with a random name?

Answer 1

There are some functions in which you can generate random strings in several languages. In PHP, you can use md5() and uniqid() , for example.

Your code is uploading the file with the name of the original file. So, if you want to avoid duplicating filenames, just generate a unique code and include to the filename. In addition, you can use the time() function to add a timestamp to the filename which will prevent duplicated filenames though.

$file_name = time() . "-" . $_FILES['image']['name'];
// output: "1615273926-filename.jpg"

If you want to invert the order of filename and the timestamp in the example above, you can use pathinfo() function. See:

$file_name_pathinfo = pathinfo($_FILES['image']['name']);
$file_name = $file_name_pathinfo['basename'] . "-" . time() . "." . $file_name_pathinfo['extension'];
// output: "filename-1615273926.jpg"

This should prevent files with duplicated names.

LEARN MORE:

• pathinfo : https://www.php.net/manual/pt_BR/function.pathinfo.php
• time() : https://www.php.net/manual/pt_BR/function.time.php

Answer 2

Try with some random numbers

$file_name = ['image']['name'];
$random = rand(000,999);
$random = str_pad($random, 3, '0', STR_PAD_LEFT);
$imgname = $random.$file_name;

In move upload

move_uploaded_file($_FILES["userImage"]["tmp_name"], "uploaddirectory/" . $imgname);

Put above line in condition check if you want for file exists

if (file_exists("uploaddirectory/" . $imgname)
     {
                echo $imgname . " already exists. ";
        die;
      }
      else
      {
       //do something
}

Answer 3

Add timestamp to the end of the file name which makes it unique.

 $fileName = time() .' '. $_FILES['image']['name'];