Disable Contact Form 7 plugin except for certain pages.

disable-cf7.php

<?php
/*
Plugin Name: Disable CF7 plugin
Plugin URI: http://www.damiencarbery.com
Description: Disable Contact Form 7 plugin except for certain pages.
Author: Damien Carbery
Version: $Revision: $

$Id: $
*/


add_filter( 'option_active_plugins', 'disable_plugins_per_page' );


function disable_plugins_per_page( $plugin_list ) {
    // Quit immediately if in admin area.
    if ( is_admin() ) {
        return $plugin_list;
    }

    $disable_plugins = array (
      // Plugin Name => Urls *not* to disable on.
      'contact-form-7/wp-contact-form-7.php' => array( '/wp-json/contact-form-7/', '/contact-us/', '/contact-us-fr/', '/kontakt/' ), // /wp-json url needed to send messages
      'advanced-custom-fields-pro/acf.php' => array( '/page-one/', '/page-two/', '/page-three/' ),
    );

    $plugins_to_disable = array();
    foreach ( $plugin_list as $plugin ) {
        if (true == array_key_exists( $plugin, $disable_plugins ) ) {
            //error_log( "Found $plugin in list of active plugins." );
            if ( false === array_search( $_SERVER['REQUEST_URI'], $disable_plugins[ $plugin ] ) ) {
                //error_log( "Disable $plugin on ".$_SERVER['REQUEST_URI']."." );
                $plugins_to_disable[] = $plugin;
            }
        }
    }

    // If there are plugins to disable then remove them from the list,
    // otherwise return the original list.
    if ( count( $plugins_to_disable ) ) {
        $new_list = array_diff( $plugin_list, $plugins_to_disable );

        return $new_list;
    }
    else {
        return $plugin_list;
    }
}