Append to PHP variable, but before '.jpg' / '.png' etc - php

Question

So I have created a basic code to upload images. The user uploads 2 images and when they are being processed/uploaded I have a small bit of code to make sure that file names aren't the same when they get uploaded to the server
if(file_exists($imgpath1)){
$imgpath1 = $imgpath1 . $random;
}
if(file_exists($imgpath2)){
$imgpath2 = $imgpath2 . $random;
}
Let's say $imgpath1 = "images/user/1.jpg" to begin with (before the PHP above is ran)
and $random is a random number generated at the start of the script, lets say $random = '255'.
The code works perfectly, and the images still display correctly, but it is adding the '255' ($random) directly to the end of the filepath, so $imgpath1 = "images/user/1.jpg255" after the code above has ran.
The file extension won't always be .jpg obviously, it could be .png, .bmp and so on...
How can I make the $random (255 in this instance) go before the ".jpg" in the filepath? I have tried researching on google but I can't seem to word it correctly to find any useful answers.
Thanks

Answer 1

You can try this code :
$filename = "file.jpg";
$append = "001";
function append_filename($filename, $append) {
preg_match ("#^(.*)\.(.+?)$#", $filename , $matches);
return $matches[1].$append.'.'.$matches[2];
}
echo append_filename($filename, $append);
It gives : file001.jpg
http://www.tehplayground.com/#JFiiRpjBX (Ctrl+ENTER for test)

Answer 2

You could do it like this:
This will extract the path and filename before the last period ($regs[1]) and the rest until the end of the string ($regs[2]).
if (preg_match('/^(.*)\.([^.].*)$/i', $imgpath1, $regs)) {
$myfilename = $regs[1] . $random . $regs[2];
} else
$myfilename = $imgpath1;
}
Works with file filenames like /path/subpath/filename.jpg or /path/subpath/filename.saved.jpg, etc.
What the Regex means:
# ^(.*)\.([^.].*)$
#
# Assert position at the beginning of the string «^»
# Match the regular expression below and capture its match into backreference number 1 «(.*)»
# Match any single character that is not a line break character «.*»
# Between zero and unlimited times, as many times as possible, giving back as needed (greedy) «*»
# Match the character “.” literally «\.»
# Match the regular expression below and capture its match into backreference number 2 «([^.].*)»
# Match any character that is NOT a “.” «[^.]»
# Match any single character that is not a line break character «.*»
# Between zero and unlimited times, as many times as possible, giving back as needed (greedy) «*»
# Assert position at the end of the string (or before the line break at the end of the string, if any) «$»

Answer 3

You can use pathinfo function to get the required aprts, and rebuild with the random part added:
if(file_exists($imgpath1)){
$pathinfo = pathinfo($imgpath1);
$imgpath1 = $pathinfo['dirname'] .'/' . $pathinfo['filename'] . $random . '.' . $pathinfo['extension'];
}
Though your $random variable will need to be a unique id, else you can still get collisions.
You will also need to filter out bad chars (people on different filesystems to your server etc). Often its just easier to replace the whole name with uniqid() . '.' . $pathinfo['extension'];