How to get image extension

Question

In my pregame, user need to upload an image, and system will rename to a serial number.

After I rename it the extension of the file is missing (.jpg/.png)

How can I get get the file extension

upload.php

$nric=$_SESSION['nric'];
if(isset($_POST['upload']))
{
    $num=(rand(10,100));
    $serialNumber = "TM".$userID.$num.$nric[7].$nric[8];
    $_FILES['file']['name']=$serialNumber;
    $file=strtoupper($_FILES['file']['name']);
    $file_loc = $_FILES['file']['tmp_name'];
    $file_size = $_FILES['file']['size'];
$folder="uploads/";  

Answer 1

Use:

pathinfo($folder.$file,PATHINFO_EXTENSION)

With this code you can get the extension of the uploaded file.

Answer 2

If $_POST['upload'] is the original file name as I asked in the comments, then:

$ext = explode(".", $_POST['upload'])[1];
echo $ext; //gives jpg, gif or whatever the extension is

Answer 3

$nric=$_SESSION['nric'];
if(isset($_POST['upload'])) {
  $file = explode(".", $_FILES["file"]["name"]);
  $newfilename = "TM".$userID.$num.$nric[7].$nric[8] . '.' . end($file);
  move_uploaded_file($_FILES["file"]["tmp_name"], "../img/imageDirectory/" . $newfilename);
}

OR

//Create a function that takes care of the randomization
function randStrGen($len){
$result = "";
$chars = "abcdefghijklmnopqrstuvwxyz0123456789$11"; //Characters allowed to produce a random string
$charArray = str_split($chars);
for($i = 0; $i < $len; $i++){
    $randItem = array_rand($charArray);
    $result .= "".$charArray[$randItem];
}
return $result;
}

$rand = randStrGen(24); //The amount of random characters needed
$nric=$_SESSION['nric']; //Session variable
if(isset($_POST['upload'])) {
 $file = explode(".", $_FILES["file"]["name"]);
 $newfilename = $rand . '.' . end($file);
 move_uploaded_file($_FILES["file"]["tmp_name"], "../img/imageDirectory/" . $newfilename); // Change this to your server's image directory
}

OR BETTER STILL

if (isset($_POST['upload']))
{
$filename = $_FILES["file"]["name"];
$file_basename = substr($filename, 0, strripos($filename, '.')); // get file extension
$file_ext = substr($filename, strripos($filename, '.')); // get file name
$filesize = $_FILES["file"]["size"];
$allowed_file_types = array('.jpg','.png','.gif','.jpeg');  

if (in_array($file_ext,$allowed_file_types) && ($filesize < 200000))
{   
    // Rename file
    $newfilename = "TM" . md5($file_basename) . $userID. $num . $file_ext;
    if (file_exists("upload/" . $newfilename))
    {
        // file already exists error
        echo "You have already uploaded this file.";
    }
    else
    {       
        move_uploaded_file($_FILES["file"]["tmp_name"], "upload/" . $newfilename);
        echo "File uploaded successfully.";     
    }
}
elseif (empty($file_basename))
{   
    // file selection error
    echo "Please select a file to upload.";
} 
elseif ($filesize > 200000)
{   
    // file size error
    echo "The file you are trying to upload is too large.";
}
else
{
    // file type error
    echo "Only these file types are allowed for upload: " . implode(', ',$allowed_file_types);
    unlink($_FILES["file"]["tmp_name"]);
}
}

What you basically need is //Change $file $file = $_FILES['file']['name']; $file_basename = substr($filename, 0, strripos($file, '.')); // get file extension