get meta description , title and image from url like facebook link sharing

Why are you using regular expression for parsing the <meta> tags ?

PHP has an in-built function for parsing the meta information , it is called the get_meta_tags()

Illustration :

<?php
$tags = get_meta_tags('http://www.stackoverflow.com/');
echo "<pre>";
print_r($tags);

OUTPUT:

Array
(
    [twitter:card] => summary
    [twitter:domain] => stackoverflow.com
    [og:type] => website
    [og:image] => http://cdn.sstatic.net/stackoverflow/img/[email protected]?v=fde65a5a78c6
    [og:title] => Stack Overflow
    [og:description] => Q&A for professional and enthusiast programmers
    [og:url] => http://stackoverflow.com/
)

As you can see the title , image and description are being parsed which you really want.

I know the question is 1.5 years old. But if you are still looking for it, you can use https://urlmeta.org. Its a free API to extract URL meta.