Do action only on certain front end pages?

Question

I am creating a plugin that allows users to insert certain code on their specified page or post of their choice. I have tried doing this:

function asdf() {

    $siteURL = get_site_url() . '/';
    $pages = get_pages();

     foreach ($pages as $page ) {

         $pageTitle = get_page_link( $page->ID );

       if ( $siteURL === $pageTitle ) {
          echo "this is the correct page" . "<br>";
       }

       else {
          echo "this is the wrong page". "<br>";
       }
    }
}

add_action('wp_head', 'asdf');

If you run this code, you will see that it treats all pages the same, and there would be no distinction in the results across different pages. However I am trying to get my function to treat each page uniquely, and give different results based on each page title.

Thanks in advance.

Answer 1

to test if you are on specific page, you just need to test the identifier like that :

add_action("wp_head", function () {

    $idPageToTest = 32867;


    if (    isset($GLOBALS["post"])
        &&  ($GLOBALS["post"]->ID === $idPageToTest)
    ) {
        echo "We are on page $idPageToTest.";
    }


}