Upload Image PHP rename file - php

Question

I am very much a beginner when it comes to PHP, however, I seemed to have my image uploader working the way I want to with the following code (sourced online). The only issue is I need to rename the files when the user uploads them to something unique like the user/date. I cannot seem to get it working when I alter this code.
I have spent some time searching here and the internet in general but I have struggled to find something that fits.
Please could someone offer me a fix or direct me in the right direction.
Thank You Stack Overflow,
class Uploader {
private $files = array();
private $extensions = array();
private $errors = array();
private $store_directory = "./attachment";
private $resize_image_library_instance = null;
public function __construct($files) {
if (is_array($files) === false) {
$files[] = $files;
}
$this->files = $files;
}
public function set_upload_to($store_directory) {
$this->store_directory = $store_directory;
}
public function set_valid_extensions($extensions, $case_sensitive = false) {
$this->extensions = $extensions;
$this->case_sensitive = $case_sensitive;
}
public function set_resize_image_library($resize_image_library_instance) {
$this->resize_image_library_instance = $resize_image_library_instance;
}
public function is_valid_extension() {
$total = count($this->files);
for($i=0; $i<$total; $i++) {
if (empty($this->files['name'][$i]) === false) {
$file_extension = $this->get_extension($this->files['name'][$i]);
if (in_array($file_extension, $this->extensions) === false) {
$this->errors['type'] = "extension";
$this->errors['file_name'] = $this->files['name'][$i];
$this->errors['file_extension'] = $file_extension;
return false;
}
}
}
return true;
}
public function run() {
$total = count($this->files);
for($i=0; $i<$total; $i++) {
if (empty($this->files['name'][$i]) === false) {
if (move_uploaded_file($this->files['tmp_name'][$i], $this->store_directory.'/'.$this->files['name'][$i]) == false) {
$this->errors['type'] = "run";
$this->errors['file_name'] = $this->files['name'][$i];
}
}
}
return empty($this->errors);
}
public function resize($scale_size = 200) {
$total = count($this->files);
for($i=0; $i<$total; $i++) {
$image = realpath($this->store_directory.'/'.$this->files['name'][$i]);
if (file_exists($image) === true && is_file($image) === true) {
$this->resize_image_library_instance->init($image);
$this->resize_image_library_instance->scale($scale_size);
if ($this->resize_image_library_instance->save($image) === false) {
$this->errors['type'] = "resize";
$this->errors['file_name'] = $image;
}
}
}
return empty($this->errors);
}
public function get_errors() {
return $this->errors;
}
//
private function get_extension($filename) {
$info = pathinfo($filename);
return $info['extension'];
}
private function get_filename($file) {
$info = pathinfo($file);
return $info['filename'];
}
}

Answer 1

To generate an unique name for the uploaded file and save it to server you can use the time(), mt_rand() and then the uploaded file's name together. Like this..
public static function generateUniqueFileName($fileName)
{
return time() . mt_rand(100, 100000) . $fileName;
}
And if you want to pre-pend the username as well then you can pass it to the method and concat it in the beginning.