Php uploaded file unique name issue - php

Question

Well, I've a html Upload form which process by .php file (uploader.php). It's a multiple file uploaded code.
So when it's upload, all files are go to upload directory with their individual file name. Like: abc.jpg, abc2.jpg etc.
But If someone upload a file with same name then it's ovrwrite the existing file. So that I need a unique name for the uploaded file. Is there any way to rename the file with unique random name. Like: 12545454.jpge, 234324324.jpge, 323453253.jpg etc..
Php Code:
<?php
if (isset($_POST['Submit'])) {
$number_of_file_fields = 0;
$number_of_uploaded_files = 0;
$number_of_moved_files = 0;
$uploaded_files = array();
$upload_directory = dirname(__file__) . '/uploaded/'; //set upload directory
/**
* we get a $_FILES['images'] array ,
* we procee this array while iterating with simple for loop
* you can check this array by print_r($_FILES['images']);
*/
for ($i = 0; $i < count($_FILES['images']['name']); $i++) {
$number_of_file_fields++;
if ($_FILES['images']['name'][$i] != '') { //check if file field empty or not
$number_of_uploaded_files++;
$uploaded_files[] = $_FILES['images']['name'][$i];
if (move_uploaded_file($_FILES['images']['tmp_name'][$i], $upload_directory .
$_FILES['images']['name'][$i])) {
$number_of_moved_files++;
}
}
}
echo "Number of File fields created $number_of_file_fields.<br/> ";
echo "Number of files submitted $number_of_uploaded_files . <br/>";
echo "Number of successfully moved files $number_of_moved_files . <br/>";
echo "File Names are <br/>" . implode(',', $uploaded_files);
}
?>

Answer 1

Use uniqid() . It is made for this.

Answer 2

You can concat time(); and session_id() or uniqid() as suggested by wormhit is also very good idea against name of each file.
Use The below code:
<?php
$target_path = "images/";
$target_path = $target_path . basename( $_FILES['uploadedfile']['name']);
if(move_uploaded_file($_FILES['uploadedfile']['tmp_name'], $target_path)) {
echo "The file ". basename( $_FILES['uploadedfile']['name']).
" has been uploaded";
} else{
echo "There was an error uploading the file, please try again!";
}
//$upload_directory = ''.uniqid().'_'.dirname(__file__) . '/uploaded/'; //set upload directory
$uploaded_file="".$upload_directory ."/".uniqid()."_".$_FILES['images']['name'][$i]."";
if (move_uploaded_file($_FILES['images']['tmp_name'][$i],$uploaded_file)) {
$number_of_moved_files++;
}
?>
<?php
if (isset($_POST['Submit'])) {
$number_of_file_fields = 0;
$number_of_uploaded_files = 0;
$number_of_moved_files = 0;
$uploaded_files = array();
$upload_directory = dirname(__file__) . '/uploaded/'; //set upload directory
/**
* we get a $_FILES['images'] array ,
* we procee this array while iterating with simple for loop
* you can check this array by print_r($_FILES['images']);
*/
for ($i = 0; $i < count($_FILES['images']['name']); $i++) {
$number_of_file_fields++;
if ($_FILES['images']['name'][$i] != '') { //check if file field empty or not
$uploaded_file="".$upload_directory ."".uniqid()."_".$_FILES['images']['name'][$i]."";
$number_of_uploaded_files++;
$uploaded_files[] = $_FILES['images']['name'][$i];
if (move_uploaded_file($_FILES['images']['tmp_name'][$i],$uploaded_file)) {
$number_of_moved_files++;
}
}
}
echo "Number of File fields created $number_of_file_fields.<br/> ";
echo "Number of files submitted $number_of_uploaded_files . <br/>";
echo "Number of successfully moved files $number_of_moved_files . <br/>";
echo "File Names are <br/>" . implode(',', $uploaded_files);
}
?>

Answer 3

You can use this
$ext = pathinfo($file_name, PATHINFO_EXTENSION);
$newfilename = substr( sha1(uniqid (rand())), 0, 10). '.'.$ext;