add_post_meta insert null value into Database

Question

l try this code :

add_post_meta($post_id, 'province', esc_attr($_POST['postProvince']), true);

checked : esc_attr($_POST['postProvince']

And it Contains Value

But add_post_meta insert null in database

it Happened only to province And city keys, other parameters insert into database correctly.

found problem area.

there is a plugin add this data to post (add_post_meta) and show into wp-admin Dashboard , method called by :

add_action( 'added_post_meta', 'ipc_add_to_post_meta', 10, 4 );

in plugin

when i try to use add_post_meta or update_post_meta insert null

wp version : 4.9.4

--------------- Update

problem is can not pass parameters using $_REQUEST And $_POST

Answer 1

Try update_post_meta function without esc_attr

<?php 
    update_post_meta($post_id, 'province', $_POST['postProvince'], true);
?>