Wordpress- Cancel post saving process - wordpress

Question

I need to abort the post saving process when the post content contains a specific string and then display a message to the user.
I found a method to display the message but didn't find a way to refuse post saving.
So far here's what i've done
add_action( "pre_post_update", "checkPost");
function checkPost($post_ID) {
$post = get_post($post_ID);
$postContent = $post->post_content;
if ( wp_is_post_revision( $post_ID ) )
return;
if(preg_match("/bad string/", $postContent) == 1) {
//
// cancel post save
//
// then
add_filter("redirect_post_location", "my_redirect_post_location_filter", 99);
}
}
function my_redirect_post_location_filter($location) {
remove_filter('redirect_post_location', __FUNCTION__, 99);
$location = add_query_arg('message', 99, $location);
return $location;
}
add_filter('post_updated_messages', 'my_post_updated_messages_filter');
function my_post_updated_messages_filter($messages) {
$messages['post'][99] = 'Publish not allowed';
return $messages;
}

Answer 1

Hope this helps you to check post content
function to_err_is_human( $post_id ) {
// If this is just a revision, don't check
if ( wp_is_post_revision( $post_id ) )
return;
$post_content = wp_unslash(!empty($_REQUEST['content']) ? $_REQUEST['content'] : $post_data['content']);
if ($post_content=="abc")
{ add_filter("redirect_post_location", "my_redirect_post_location_filter", 99);}
}
add_action( 'save_post', 'to_err_is_human' );
function my_redirect_post_location_filter($location) {
remove_filter('redirect_post_location', __FUNCTION__, 99);
$location = add_query_arg('message', 99, $location);
return $location;
}
add_filter('post_updated_messages', 'my_post_updated_messages_filter');
function my_post_updated_messages_filter($messages) {
$messages['post'][99] = 'Publish not allowed';
return $messages;
}