Advanced Custom Fields ACF dynamically set default value #wordpress

functions.php

<?php
add_filter('acf/load_field/name=field_name', function($field) {
     
    // variant 1
    $field['default_value'] = 'FOO';

    // variant 2 (does not work anymore)
    // use get_post_meta instead of get_field to avoid conflicts
    global $post;
    if( get_post_meta($post->ID, 'field_name', true) == '' ) {
        $field['value'] = 'FOO';
    }

    // if field should be disabled
    $field['disabled'] = 1;
    
    return $field; 
    
});

Does this work?

function lf_get_price($post_id) {
    return 42;
}

add_filter('acf/load_field/name=precio_lifehuni', function($lf_field) {
    global $post;
    $lf_field['default_value'] = lf_get_price($post->ID);
    return $lf_field;
});

Does this work?

function lf_get_price($post_id) {
    return 42;
}

add_filter('acf/load_field/name=precio_lifehuni', function($lf_field) {
    global $post;
    $lf_field['default_value'] = lf_get_price($post->ID);
    return $lf_field;
});

That worked. What you discovered?

This portion of your code simply returns nothing.

    $var_id = get_field('id_producto_lifehuni', $post_id);
    $ch_lf = curl_init('https://app.milifehuni.com/public/ws/get_price/'.$var_id);
    curl_setopt($ch_lf, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch_lf, CURLOPT_HEADER, 0);
    $lf_data = curl_exec($ch_lf);
    curl_close($ch_lf);
    return $lf_data;

This has nothing to do with ACF / default values, you have to check, why curl doesn't return anything.

This portion of your code simply returns nothing.

    $var_id = get_field('id_producto_lifehuni', $post_id);
    $ch_lf = curl_init('https://app.milifehuni.com/public/ws/get_price/'.$var_id);
    curl_setopt($ch_lf, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch_lf, CURLOPT_HEADER, 0);
    $lf_data = curl_exec($ch_lf);
    curl_close($ch_lf);
    return $lf_data;

This has nothing to do with ACF / default values, you have to check, why curl doesn't return anything.

Yeah, doing some testing here aswell it looks like the curl its not running when its called or its data is not being captured. Have no idea how, why or what to do.

Got it to work, actually your update to the post helped me a lot. But the Disabled, didnt work. Thank you so much, you relieved me 3 days of full stress... Now the problem is that it takes time to load the pages.

<?php
add_filter('acf/load_value/name=precio_lifehuni', function($field) {
    global $post;
    $var_id = get_post_meta($post->ID, 'id_producto_lifehuni', true);
    $ch_lf = curl_init('https://app.milifehuni.com/public/ws/get_price/'.$var_id);
    curl_setopt($ch_lf, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch_lf, CURLOPT_HEADER, 0);
    $lf_data = curl_exec($ch_lf);
    curl_close($ch_lf);
    return $lf_data;
    get_post_meta($post->ID, 'precio_lifehuni', true);
    $field['default_value'] = $lf_data;
    $field['disabled'] = 1;
    return $field; 
});

For the ones who are looking for a solution:

<?php
add_filter('acf/load_field/name=field_name', function($field) {
     
    // variant 1
    $field['default_value'] = 'FOO';

    // variant 2 (does work with most recent ACF plugin)

    if( get_post_meta($post->ID, 'field_name', true) == '' ) {
        $field['value'] = 'FOO';
    }
    
    return $field; 
    
});

This code works when you remove global $post;.

Most probably you are already setting this, so it will give a Cannot Modify Header Information – Headers Already Sent error. That error will not show the text you would like to fetch.