Credit link that if removed stops site from working

Question

Im trying add a credit link to the footer of all the WP sites i make saying:

Designed by ...

While this is simple enough, i want to code it so that if this link is removed from the footer, the entire site shows an error or doesn't load up etc.

Any one have ideas?

Answer 1

While I believe the premise of this to be flawed and somewhat black-hat, it is a legit WP question albeit a futile exercise.

You can do something like the following:

add_action('template_redirect', 'foobar_explode_if_no_citation');
function foobar_explode_if_no_citation(){

    #Get the absolute server path to footer.php
    $footer_path = locate_template('footer.php');

    #Store the footer file contents in a var
    $footer_contents = file_get_contents($footer_path);

    #The required string
    $citation_string = 'Designed by Foo Bar';

    #Set off the nuclear bomb if there is an egregious offense
    if(!preg_match("/$citation_string/", $footer_contents))
        exit('All your websitez are belong to me. Make sure this string "Designed by Foo Bar" is included in footer.php');
}

I hope you get my tongue-in-cheek innuendoes regarding what a bad user experience this would be. :)

Caveat

As noted in the comments, there are innumerable ways to route this approach, and any approach for that matter. Anyone can easily reverse engineer any mechanism put in place.