PHP Overwrite Uploaded Image - php

Question

I am trying some file upload code which I Googled.
Now Issue is when I try to upload image and if its already in folder then its over write and issues come. I Try Code From here and here as well but I face some error.
Here is my code. Can I do in this code that its upload file with some extra name which stop over write of existing file??
if(isset($_REQUEST['main']))
{
$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")) && ($_FILES["file"]["size"] < 20000) && in_array($extension, $allowedExts)) {*/
if ($_FILES["file"]["error"] > 0) {
echo "Return Code: " . $_FILES["file"]["error"] . "<br>";
} else {
if (file_exists("upload/" . $_FILES["file"]["name"])) {
echo $_FILES["file"]["name"] . " already exists. ";
} else {
if( move_uploaded_file($_FILES["file"]["tmp_name"], "../img/catalog/" . $_FILES["file"]["name"]) ){
$filepath = "img/catalog/" . $_FILES["file"]["name"];
}else{
echo $_FILES["file"]["name"]." unable to store";
}
}
/*}
} else {
echo "Invalid file";
}*/
}
$main = $_REQUEST['main'];
$sql="INSERT INTO image VALUES ('', '$filepath', '$main')";
if (!mysqli_query($con,$sql)) {
die('Error: ' . mysqli_error($con));
}
echo "1 record added";
}

Answer 1

You can check if the file exists using file_exists.
If it exist, add some extra characters to the file name. Then you can save it.
Here is a function that generates random characters :
function randomString($length) {
$str="";
$chars = "subinsblogabcdefghijklmanopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
$size = strlen($chars);
for($i = 0;$i < $length;$i++) {
$str .= $chars[rand(0,$size-1)];
}
return $str;
}
Replace the code :
if( move_uploaded_file($_FILES["file"]["tmp_name"], "../img/catalog/" . $_FILES["file"]["name"]) ){
$filepath = "img/catalog/" . $_FILES["file"]["name"];
}else{
echo $_FILES["file"]["name"]." unable to store";
}
with :
$newLocation = "../img/catalog/" . $_FILES["file"]["name"];
if(file_exists($newLocation)){
$newLocation .= randomString(10); // We append 10 new characters
}
if( move_uploaded_file($_FILES["file"]["tmp_name"], $newLocation) ){
$filepath = str_replace("../img", "img", $newLocation); // make File Path starting with img/
}else{
echo $_FILES["file"]["name"]." unable to store";
}
The above code will check if the file exists. If yes, then a string of 10 random characters is appended to the file name and stored in the destination folder.

Answer 2

You didnt mention your problem but I think you have missed a point in your
if else
part. write it like this :
if (file_exists("upload/" . $_FILES["file"]["name"])) {
echo $_FILES["file"]["name"] . " already exists. ";
$_FILES["file"]["name"] = $_FILES["file"]["name"].$your_new_number;
}
if( move_uploaded_file($_FILES["file"]["tmp_name"], "../img/catalog/" . $_FILES["file"]["name"]) ){
$filepath = "img/catalog/" . $_FILES["file"]["name"];
}else{
echo $_FILES["file"]["name"]." unable to store";
}
}