php replace url in string with totally new url

Question

I am currently working on a short url script to work with twitter.

Currently i am entering my desired tweet text into a textarea with a long url. So far i have the following which detects the url:

$regex = "/(http|https|ftp|ftps)\:\/\/[a-zA-Z0-9\-\.]+\.[a-zA-Z]{2,3}(\/\S*)?/";
if ( preg_match( $regex, $text, $url ) ) { // $url is now the array of urls
   echo $url[0];
}

When a tweet is entered it will look something like this:

hi here is our new product, check it out: www.mylongurl.com/this-is-a-very-long-url-and-needs-to-be-shorter

I am then generating some random characters to append on the end of a new url, so it will end up something like this: shorturl.com/ghs7sj.

When clicking, shorturl.com/ghs7sj it redirects you to www.mylongurl.com/this-is-aver-long-url-and-needs-to-be-shorter. This all works fine.

My question is the tweet text still contains the long url. Is there a way i can replace the long url with the short one? Do i need some new code? or can i adapt the above to also do this?

My desired outcome is this:

 hi here is our new product, check it out: shorturl.com/ghs7sj

This is based on wordpress so all information is currently stored in the posts and post_meta tables. Just a note that there will only ever be 1 url in the tweet.

Answer 1

Can you just use PHP's str_replace() function? Something like

str_replace($url, $short_url, $text);

Answer 2

You can do the replacement inside a callback function by using preg_replace_callback():

$regex = "/(http|https|ftp|ftps)\:\/\/[a-zA-Z0-9\-\.]+\.[a-zA-Z]{2,3}(\/\S*)?/";
$text = preg_replace_callback($regex, function($url) { 
    // do stuff with $url[0] here
    return make_short_url($url[0]);
}, $text);