Edit .htaccess on plugin deactivate

Question

1. I am trying to add rewrite rules in .htaccess during plugin activation. How can I edit/roll-back rewrite rules in .htaccess on plugin deactivation?

   function add_to_htaccess( $rules ) {
       $content = <<<EOD
       \nAddOutputFilterByType DEFLATE text/plain
       AddOutputFilterByType DEFLATE text/html
       AddOutputFilterByType DEFLATE text/xml
       AddOutputFilterByType DEFLATE text/css
       AddOutputFilterByType DEFLATE application/xml
       AddOutputFilterByType DEFLATE application/xhtml+xml
       AddOutputFilterByType DEFLATE application/rss+xml
       AddOutputFilterByType DEFLATE application/javascript
       AddOutputFilterByType DEFLATE application/x-javascript
       AddOutputFilterByType DEFLATE application/x-httpd-php
       AddOutputFilterByType DEFLATE application/x-httpd-fastphp
       AddOutputFilterByType DEFLATE image/svg+xml
       SetOutputFilter DEFLATE\n\n
       EOD;
       return $content . $rules;
   }
   add_filter('mod_rewrite_rules', 'add_to_htaccess');
   
   function myplugin_enable_flush_rules() {
       global $wp_rewrite;
       $wp_rewrite->flush_rules();
   }
   register_activation_hook( __FILE__, 'myplugin_enable_flush_rules' );
   

2. The above function adds rewrite rules with in default WordPress rules lies between # BEGIN WordPress and # END WordPress. What could I do to add it separately (at the bottom of .htaccess ?)

Answer 1

I have managed to do this at my own. Below is the function I have added.

function myplugin_deactivate() {
    // This will remove the rewrite rules
    remove_filter('mod_rewrite_rules', 'add_to_htaccess');

    global $wp_rewrite;

    // Flush the rewrite rules
    $wp_rewrite->flush_rules();
}
register_deactivation_hook( __FILE__, 'myplugin_deactivate' );