Assign Category to User (and set that category to their posts)

Hello there,

To achieve this, you’ll need to create a custom user profile field for selecting a category and then use that field to programmatically set the category of posts created by the user.

You can use the user_contactmethods hook to add a custom field to the user profile. Here’s how you can do that:

// Add custom user profile field
function add_user_category_field($user) {
$categories = get_categories();
$selected_category = get_user_meta($user->ID, 'user_category', true);
?>
<h3><?php _e("User Category", "blank"); ?></h3>
<table class="form-table">
<tr>
<th><label for="user_category"><?php _e("Category"); ?></label></th>
<td>
<select name="user_category" id="user_category">
<option value="">Select a category</option>
<?php foreach ($categories as $category) : ?>
<option value="<?php echo esc_attr($category->term_id); ?>" <?php selected($selected_category, $category->term_id); ?>>
<?php echo esc_html($category->name); ?>
</option>
<?php endforeach; ?>
</select>
<br /><span class="description"><?php _e("Select a category for this user."); ?></span>
</td>
</tr>
</table>
<?php
}
add_action('show_user_profile', 'add_user_category_field');
add_action('edit_user_profile', 'add_user_category_field');
// Save the custom user profile field
function save_user_category_field($user_id) {
if (!current_user_can('edit_user', $user_id)) {
return false;
}
update_user_meta($user_id, 'user_category', $_POST['user_category']);
}
add_action('personal_options_update', 'save_user_category_field');
add_action('edit_user_profile_update', 'save_user_category_field');

Next, you need to set the category of a post programmatically based on the user profile. You can use the save_post hook for this:

function set_post_category_based_on_user($post_id) {
// Check if it's a valid post and not an autosave
if (defined('DOING_AUTOSAVE') && DOING_AUTOSAVE) {
return;
}
// Check if it's a post and not a revision
if (get_post_type($post_id) != 'post') {
return;
}
// Get the user ID of the author
$author_id = get_post_field('post_author', $post_id);
// Get the category assigned to the user
$user_category = get_user_meta($author_id, 'user_category', true);
if ($user_category) {
// Set the post's category
wp_set_post_categories($post_id, array($user_category));
}
}
add_action('save_post', 'set_post_category_based_on_user');

You will need to add this code to your theme functions.php file or via Code Snippet plugin. Give it a try but beware, adding code like this can cause a fatal error on your site if something is off, make sure you can undo the code change if things go south.

Summary

1. Add a custom field to the user profile to select a category from existing categories.
2. Save the selected category when the user profile is updated.
3. Automatically set the category of new posts based on the user’s selected category when the post is saved.

This approach should provide a clean solution without relying on complex plugins.

Kind Regards.

Hi @wpmajestic , this is a fantastic answer, thank you very much! I adjusted the method

add_user_category_field

slightly to show empty categories as well:

	$args = array("hide_empty" => 0,
"type"      => "post",      
"orderby"   => "name",
"order"     => "ASC" );
$categories = get_categories($args);

Appreciate your answer, I bookmarked your website in case I need a good WP hosting 🙂