add_filter not working inside if function

Question

I want to edit the content before save to database for the first time only when add a new post, so i check the path if it's at the post-new.php i want to apply the filter, but it's not working. anyone know how to solve this ?

$pagePath = parse_url( $_SERVER['REQUEST_URI'] );
$pagePath = $pagePath['path'];
$pagePath = substr($pagePath, 1);

if($pagePath === 'wp-admin/post-new.php'){
    function my_filter_function_name( $content ) {
        return $content . 'text before save to db';
    }

    add_filter( 'content_save_pre', 'my_filter_function_name', 10, 1 );
}

Answer 1

No need to write this too much code.

$pagePath = parse_url( $_SERVER['REQUEST_URI'] );
$pagePath = $pagePath['path'];
$pagePath = substr($pagePath, 1);

you can easily get current page path by calling global variable $pagenow.

global $pagenow; // return 'post-new.php'

Instead of using content_save_pre filter you can do this same with wp_insert_post_data filter more easily. try out this.

add_filter( 'wp_insert_post_data', 'appendContent', 99, 2 );

function appendContent( $data, $postarr ) {  

       // Retrieve referer path of current page through wp_get_referer(). 
       $referer = basename( wp_get_referer() );  // post-new.php

       if ( ! wp_is_post_revision( $postarr['ID'] ) && $referer == 'post-new.php' ) {

             $data['post_content'] = $data['post_content'] . ' text before save to db';
        }
    return $data;
}

wp_insert_post_data is called by the wp_insert_post function prior to inserting into or updating the database.

Answer 2

I did not understand your logic to check if it is first time. If your logic is correct, if condition should be inside the filter function.

$pagePath = parse_url( $_SERVER['REQUEST_URI'] );
$pagePath = $pagePath['path'];
$pagePath = substr($pagePath, 1);


function my_filter_function_name( $content ) {
    if($pagePath === 'wp-admin/post-new.php')
    {
        return $content . 'text before save to db';
    }
}

add_filter( 'content_save_pre', 'my_filter_function_name', 10, 1 );