Only replace own website url in text with HTML links

When user post a comment, i strip all the html tags in the comment before insert into my database because i do not want them to post external links(SPAM) in the comment. But i only want to strip external links, i want to display my own website URL as normal clickable links. How to detect the URL is my own website's URL and make it clickable as usual?

Example in the comment: Blah... blah... blah... http://my_website_url.com Blah... blah... blah... Blah... blah... blah... Blah... blah... blah... Blah... blah... blah... Blah... blah... blah...http://external_links.com Blah... blah... blah... Blah... blah... blah...

As above example, i want ONLY http://my_website_url.com become clickable link before insert into my database. (http://my_website_url.com to < a href="http://my_website_url.com" >http://my_website_url.com< /a > )

Also, not only detect the main URL:http://my_website_url.com, but also:

-http://www.my_website_url.com

-www.my_website_url.com

-my_website_url.com

-http://my_website_url.com/blah/blah/blah

-http://www.my_website_url.com/blah/blah/blah

-www.my_website_url.com/blah/blah/blah

-my_website_url.com/blah/blah/blah

or any URLs that from my website:http://www.my_website_url.com/xxx/xxx/xxx/xxx

If could, please post exactly php codes to let me copy and paste into my file because i have little knowledge with php only. Thanks guys.

 

Use preg_replace_callback() along with parse_url() (with the host option for comparison), refer to the documentation pages for notes/comments on usage.