[php] How to rename uploaded file before saving it into a directory?

Below is the code I used in order to upload files into a directory. It works fine. My main question is:

move_uploaded_file() is the one that saves the uploaded file into the directory, and it is also my guess that move_uploaded_file() is the one that sets the name for it.

How could I change the name of my file to a random number?

I have tried to do so below:

$allowedExts = array("gif", "jpeg", "jpg", "png");
$temp = explode(".", $_FILES["file"]["name"]);
$extension = end($temp);
if ((($_FILES["file"]["type"] == "image/gif") || ($_FILES["file"]["type"] == "image/jpeg") || ($_FILES["file"]["type"] == "image/jpg") || ($_FILES["file"]["type"] == "image/pjpeg") || ($_FILES["file"]["type"] == "image/x-png") || ($_FILES["file"]["type"] == "image/png")) && ($_FILES["file"]["size"] < 100000) && in_array($extension, $allowedExts)) {
    if ($_FILES["file"]["error"] > 0) {
        echo "Return Code: " . $_FILES["file"]["error"] . "<br>";
    } else {

        $fileName = $temp[0] . "." . $temp[1];
        $temp[0] = rand(0, 3000); //Set to random number
        $fileName;

        if (file_exists("../img/imageDirectory/" . $_FILES["file"]["name"])) {
            echo $_FILES["file"]["name"] . " already exists. ";
        } else {
            move_uploaded_file($_FILES["file"]["tmp_name"], "../img/imageDirectory/" . $_FILES["file"]["name"]);
            echo "Stored in: " . "../img/imageDirectory/" . $_FILES["file"]["name"];
        }
    }
} else {
    echo "Invalid file";
}

I tried changing variables such as the $_FILES["file"]["name"] and replacing it with the $fileName; variable so that the new name can be stored.

You can Try this,

$newfilename= date('dmYHis').str_replace(" ", "", basename($_FILES["file"]["name"]));

move_uploaded_file($_FILES["file"]["tmp_name"], "../img/imageDirectory/" . $newfilename);

/* create new name file */
$filename   = uniqid() . "-" . time(); // 5dab1961e93a7-1571494241
$extension  = pathinfo( $_FILES["file"]["name"], PATHINFO_EXTENSION ); // jpg
$basename   = $filename . "." . $extension; // 5dab1961e93a7_1571494241.jpg

$source       = $_FILES["file"]["tmp_name"];
$destination  = "../img/imageDirectory/{$basename}";

/* move the file */
move_uploaded_file( $source, $destination );

echo "Stored in: {$destination}";

You guess correctly. Read the manual page for move_uploaded_file. Set the second parameter to whereever your want to save the file.

If it doesn't work, there is something wrong with your $fileName. Please post your most recent code.

The move_uploaded_file will return false if the file was not successfully moved you can put something into your code to alert you in a log if that happens, that should help you figure out why your having trouble renaming the file