# Module actions in the header
← [To the overview of UI contributions](contributions.md)
`admin_extension.header` adds its own action to the right side of the header
module. This could be a command icon, a dropdown with a short list, or a button,
which opens a modal window.
Don't use header input instead of notifications: events that require attention
are added to the general [bell](notifications.md).
## 1. Description in `module.php`
```php
use App\Adminx\Todo\Topbar;
'header' => array(
'code' => 'quick_add',
'label' => 'Быстрое создание задачи',
'icon' => 'ti ti-list-check',
'template' => '@todo/topbar.twig',
'modal_template' => '@todo/modal.twig',
'provider' => array(Topbar::class, 'data'),
'permission' => 'view_todos',
'sort_order' => 20,
),
```
- `template` is included directly inside `.topbar-right`.
- `modal_template` is optional and is included at the end of ``, where the modal
the window is not limited by the size of the header.
- both templates receive the same `module_data` and `module_header`.
- contributions can be disabled by placing the module in the interface.
## 2. Provider
The header data provider runs on **every dashboard page**,
therefore there must be
cheap and take into account the current user:
```php
class Topbar
{
public static function data()
{
$userId = (int) Auth::id();
if ($userId < 1) {
return array('enabled' => false);
}
return array(
'enabled' => true,
'pending' => Model::pendingCount($userId),
'items' => Model::pending($userId, 5),
'can_manage' => Permission::check('manage_todos'),
);
}
}
```
Do not upload a complete list of entries. For badge you need `COUNT`, for dropdown -
small `LIMIT`. A single provider should not make external HTTP requests.
## 3. Button and dropdown
```twig
{% if module_data.enabled %}
{% endif %}
```
Use `btn-icon`, Tabler icon, `data-tooltip` and `aria-label`. Badge
limit the display to `99+` so that the number does not change the geometry of the header.
Dropdown opens general `Adminx.Dropdown`; custom click handler for
no regular opening required.
## 4. Modal action
`modal_template` is suitable for quickly creating a record. The form must have
server route with CSRF and recheck `manage_*`:
```twig
{% if module_data.can_manage %}
{% endif %}
```
The module's JavaScript submits the form via a common Ajax contract, shows Toast,
updates badge/dropdown and closes the window only after a successful response. Not
use `window.alert`, `confirm` or `prompt`.
## 5. Assets and several actions
Since the header is present on all pages, its CSS/JS is registered in
manifest, and not just the section controller. The ID and data attribute names must be
contain the module code so that several contributions do not conflict.
`header` can be a list of descriptions. Every action must have
unique `code`, `sort_order`, templates and minimum required rights.
## Check
- the action is not visible without `permission`;
- provider does not create N+1 and runs quickly on any page;
- dropdown is closed by a common mechanism and is not cut off;
- the modal window is accessible from the keyboard and closes after success;
- POST checks CSRF and entitlement regardless of button visibility;
- badge and long text do not move the rest of the header elements;
- turning off placement or module completely removes the contribution.