how to redirect non php extension url to php extension url htaccess?

Question

I have added .php extension to all my pages in wordpress through functions.php.

My Code -

<?php
// Do NOT include the opening PHP tag

// Add .PHP to page permalinks
add_action('init', 'ss_php_pages', -1);
function ss_php_pages() {
    global $wp_rewrite;
    
    if ( !strpos($wp_rewrite->get_page_permastruct(), '.php')){
            $wp_rewrite->page_structure = $wp_rewrite->page_structure . '.php';
    }
    
    $wp_rewrite->flush_rules();
}

// Remove slash from page permalinks
add_filter('user_trailingslashit', 'no_page_slash_on_ss',66,2);
function no_page_slash_on_ss($string, $type){
    global $wp_rewrite;
    
    if ($wp_rewrite->using_permalinks() && $wp_rewrite->use_trailing_slashes==true && $type == 'page'){
        return untrailingslashit($string);
    }else{
       return $string;
      }
}

Now I want to redirect my old link (example.com/demo) to new link (example.com/demo.php).. I have many pages there so I can't add redirection for each manually.

Additional information: I have added .php extension to my Wordpress pages (example.com/demo + .php). Now My Old Links (example.demo or example.com/anything) which were without .php, got 404 because I have added .php to them so they have modified. Now I want to redirect my all old links like example.com/demo to example.com/demo.php or example.com/xyz to example.com/xyz.php to not to loss traffic or getting broken link.

Answer 1

Could you please try following htaccess Rules. Make sure htaccess is present in root folder.

Make sure to clear your browser cache before testing your URLs.

RewriteEngine on
##User is using wordpress without this rule it was adding .php to home page too which was NOT needed, hence this rule is been added.
RewriteRule ^/?$ / [R=301,END]

##Major rules for links which are non php and should be served with php format files.
RewriteCond %{DOCUMENT_ROOT}/$1.php -f [NC]
RewriteCond %{REQUEST_URI} !\.php/?$ [NC]
RewriteRule ^(.*)/?$ $1.php [L,R=301]

For JS/CSS rewrite: You may need to use base tag to fix your js and other relative resources. If you are linking js files using a relative path then the file will obviously get a 404 because its looking for URL path. for example if the URL path is /file/ instead of file.html then your relative resources are loading from /file/ which is not a directory but rewritten html file. To fix this make your links absolute or use base tag. In the header of your webpage add this <base href="/"> so that your relative links can load from the correct location.