Control Panel Edit Pages

Modules and plugins can add new edit pages to the control panel, for editing models or elements.

First, decide on the URL patterns that the edit page should be accessed by, such as my-plugin/events/new when creating a new event, and my-plugin/events/X for editing an existing one.

Register two URL rules via craft\web\UrlManager::EVENT_REGISTER_CP_URL_RULES (opens new window) from your module/plugin’s init() method:

use craft\events\RegisterUrlRulesEvent;
use craft\web\Urlmanager;
use yii\base\Event;

Event::on(
    UrlManager::class,
    UrlManager::EVENT_REGISTER_CP_URL_RULES,
    function(RegisterUrlRulesEvent $event) {
        $event->rules['my-plugin/events/new'] = 'my-plugin/events/edit';
        $event->rules['my-plugin/events/<eventId:\d+>'] = 'my-plugin/events/edit';
    }
);

Now create a new form page template that contains the edit form, such as templates/events/_edit.twig.

The model being edited will be available to the template as a predefined variable (e.g. event). The template can refer to that model when passing current field values and validation errors to the form inputs.

{% extends '_layouts/cp' %}
{% import '_includes/forms' as forms %}

{% set title = 'Edit Event'|t('my-plugin') %}
{% set fullPageForm = true %}

{% block content %}
    {# Have the form submit to a my-plugin/events/save controller action #}
    {{ actionInput('my-plugin/events/save') }}
    
    {# Have the save action redirect to /my-plugin/events afterward #}
    {{ redirectInput('my-plugin/events') }}

    {{ forms.textField({
      label: 'Event Name'|t('plugin-handle'),
      instructions: 'The name of the event'|t('plugin-handle'),
      id: 'name',
      name: 'name',
      value: event.name,
      required: true,
      errors: event.getErrors('name'),
    }) }}
    
    {{ forms.dateField({
      label: 'Start Date'|t('plugin-handle'),
      instructions: 'The start date of the event.'|t('plugin-handle'),
      id: 'start-date',
      name: 'startDate',
      value: event.startDate,
      required: true,
      errors: event.getErrors('startDate'),
    }) }}
    
    {{ forms.dateField({
      label: 'End Date'|t('plugin-handle'),
      instructions: 'The end date of the event.'|t('plugin-handle'),
      id: 'end-date',
      name: 'endDate',
      value: event.endDate,
      required: true,
      errors: event.getErrors('endDate'),
    }) }}
{% endblock %}

Once the template is ready, create controller actions for displaying the edit page, and handling form submissions.

use mynamespace\models\Event;
use Craft;
use craft\helpers\DateTimeHelper;
use yii\web\BadRequestHttpException;
use yii\web\Response;

public function actionEdit(?int $eventId = null, ?Event $event = null): Response
{
    // Ensure the user has permission to save events
    $this->requirePermission('edit-events');

    if (!$event) {
        // Are we editing an existing event?
        if ($eventId) {
            $event = MyPlugin::getInstance()->events->getEventById($eventId);
            if (!$event) {
                throw new BadRequestHttpException("Invalid event ID: $eventId");
            }
        } else {
            // We're creating a new event
            $event = new Event();
        }
    }
    
    return $this->renderTemplate('plugin-handle/events/_edit', [
        'event' => $event,
    ]);
}

public function actionSave(): ?Response
{
    // Ensure the user has permission to save events
    $this->requirePermission('edit-events');

    $eventId = $this->request->getBodyParam('eventId');
    
    if ($eventId) {
        $event = MyPlugin::getInstance()->events->getEventById($eventId);
        if (!$event) {
            throw new BadRequestHttpException("Invalid event ID: $eventId");
        }
    } else {
        $event = new Event();
    }
    
    // Populate the event with the form data
    $event->name = $this->request->getBodyParam('name');
    $event->startDate = DateTimeHelper::toDateTime($this->request->getBodyParam('startDate'));
    $event->endDate = DateTimeHelper::toDateTime($this->request->getBodyParam('endDate'));
    
    // Try to save it
    if (!MyPlugin::getInstance()->events->saveEvent($event)) {
        if ($this->request->acceptsJson) {
            return $this->asJson(['errors' => $event->getErrors()]);
        }

        $this->setFailFlash(Craft::t('plugin-handle', 'Couldn’t save event.'));
        
        // Send the event back to the edit action
        Craft::$app->urlManager->setRouteParams([
            'event' => $event,
        ]);
        return null;
    }
    
    if ($this->request->acceptsJson) {
        return $this->asJson(['success' => true]);
    }
    
    $this->setSuccessFlash(Craft::t('plugin-handle', 'Event saved.'));
    $this->redirectToPostedUrl($event);
}

On the surface, these look like two distinct actions—one for showing the edit page, and another for handling form submissions.

But there’s one scenario where both of these actions will get run, one after the other: when there are validation errors on save.

If the saveEvent() method returns false (presumably due to validation errors), our save action registers the model as a route param called event, by passing it to craft\web\UrlManager::setRouteParams() (opens new window). Then the action will return null, which tells Craft it should continue routing the request as if it was never routed to our save action to begin with.

The next stop in the routing will be our edit action, per the URL rules we’ve registered. This time, our (invalid) model will be passed to its $event argument, so the action won’t need to fetch/create an event based on the $eventId. It will pass the model to the edit template, complete with validation errors.

See Model Operation Methods for a blueprint of how the service’s saveEvent() method might work.