The Basics

php artisan nova:resource Post

/**
 * The model the resource corresponds to.
 *
 * @var string
 */
public static $model = 'App\Models\Post';

use App\Nova\User;
use App\Nova\Post;

/**
 * Register the application's Nova resources.
 *
 * @return void
 */
protected function resources()
{
    Nova::resourcesIn(app_path('Nova'));

    Nova::resources([
        User::class,
        Post::class,
    ]);
}

/**
 * Indicates if the resource should be displayed in the sidebar.
 *
 * @var bool
 */
public static $displayInNavigation = false;

use Illuminate\Http\Request;

/**
 * Get the menu that should represent the resource.
 *
 * @param  \Illuminate\Http\Request  $request
 * @return \Laravel\Nova\Menu\MenuItem
 */
public function menu(Request $request)
{
    return parent::menu($request)->withBadge(function () {
        return static::$model::count();
    });
}

/**
 * The logical group associated with the resource.
 *
 * @var string
 */
public static $group = 'Admin';

/**
 * The visual style used for the table. Available options are 'tight' and 'default'.
 *
 * @var string
 */
public static $tableStyle = 'tight';

/**
 * Whether to show borders for each column on the X-axis.
 *
 * @var bool
 */
public static $showColumnBorders = true;

/**
 * The click action to use when clicking on the resource in the table.
 *
 * Can be one of: 'detail' (default), 'edit', 'select', 'preview', or 'ignore'.
 *
 * @var string
 */
public static $clickAction = 'edit';

/**
 * The relationships that should be eager loaded on index queries.
 *
 * @var array
 */
public static $with = ['user'];

/**
 * Return a replicated resource.
 *
 * @return static
 *
 * @throws \InvalidArgumentException
 */
public function replicate()
{
    return tap(parent::replicate(), function ($resource) {
        $model = $resource->model();

        $model->name = 'Duplicate of '.$model->name;
    });
}

namespace App\Observers;

use App\Models\Post;
use Laravel\Nova\Http\Requests\NovaRequest;
use Laravel\Nova\Nova;

class PostObserver
{
    /**
     * Handle the creation of a new Post.
     *
     * @param  \App\Models\Post  $model
     * @return void
     */
    public function creating(Post $model): void
    {
        Nova::whenServing(function (NovaRequest $request) use ($model) {
            $model->parent_id = $request->input('fromResourceId');
        });
    }
}

namespace App\Providers;

use App\Models\User;
use App\Observers\UserObserver;
use Illuminate\Support\ServiceProvider;

class AppServiceProvider extends ServiceProvider
{
    /**
     * Bootstrap any application services.
     *
     * @return void
     */
    public function boot()
    {
        parent::boot();

        User::observe(UserObserver::class);
    }

    /**
     * Register the service provider.
     *
     * @return void
     */
    public function register()
    {
        //
    }
}

use App\Models\User;
use Laravel\Nova\Observable;
use App\Observers\UserObserver;

/**
 * Bootstrap any application services.
 *
 * @return void
 */
public function boot()
{
    parent::boot();

    Observable::make(User::class, UserObserver::class);
}

namespace App\Observers;

use App\Models\User;
use Illuminate\Http\Request;
use Laravel\Nova\Http\Requests\NovaRequest;
use Laravel\Nova\Nova;

class UserObserver
{
    /**
     * Handle the User "created" event.
     *
     * @param  \App\Models\User  $user
     * @return void
     */
    public function created(User $user)
    {
        Nova::whenServing(function (NovaRequest $request) use ($user) {
            // Only invoked during Nova requests...
        }, function (Request $request) use ($user) {
            // Invoked for non-Nova requests...
        });

        // Always invoked...
    }
}

use App\Models\User;
use App\Nova\Resource;
use Illuminate\Database\Eloquent\Model;
use Laravel\Nova\Http\Requests\NovaRequest;

class User extends Resource
{
    /**
     * Register a callback to be called after the resource is created.
     *
     * @param  \Laravel\Nova\Http\Requests\NovaRequest  $request
     * @param  \Illuminate\Database\Eloquent\Model  $model
     * @return void
     */
    public static function afterCreate(NovaRequest $request, Model $model)
    {
        $model->sendEmailVerificationNotification();
    }
}

/**
 * Indicates whether Nova should check for modifications between viewing and updating a resource.
 *
 * @var bool
 */
public static $trafficCop = false;

/**
 * Indicates whether Nova should check for modifications between viewing and updating a resource.
 *
 * @param  \Illuminate\Http\Request  $request
 * @return  bool
*/
public static function trafficCop(Request $request)
{
    return static::$trafficCop;
}

/**
 * Indicates whether the resource should automatically poll for new resources.
 *
 * @var bool
 */
public static $polling = true;

/**
 * The interval at which Nova should poll for new resources.
 *
 * @var int
 */
public static $pollingInterval = 5;

/**
 * Indicates whether to show the polling toggle button inside Nova.
 *
 * @var bool
 */
public static $showPollingToggle = true;

use Laravel\Nova\URL;

return URL::remote('https://nova.laravel.com');

/**
 * Return the location to redirect the user after creation.
 *
 * @param  \Laravel\Nova\Http\Requests\NovaRequest  $request
 * @param  \Laravel\Nova\Resource  $resource
 * @return \Laravel\Nova\URL|string
 */
public static function redirectAfterCreate(NovaRequest $request, $resource)
{
    return '/resources/'.static::uriKey().'/'.$resource->getKey();
}

/**
 * Return the location to redirect the user after update.
 *
 * @param  \Laravel\Nova\Http\Requests\NovaRequest  $request
 * @param  \Laravel\Nova\Resource  $resource
 * @return \Laravel\Nova\URL|string
 */
public static function redirectAfterUpdate(NovaRequest $request, $resource)
{
    return '/resources/'.static::uriKey().'/'.$resource->getKey();
}

/**
 * Return the location to redirect the user after deletion.
 *
 * @param  \Laravel\Nova\Http\Requests\NovaRequest  $request
 * @return \Laravel\Nova\URL|string|null
 */
public static function redirectAfterDelete(NovaRequest $request)
{
    return null;
}

'pagination' => 'links',

/**
 * The pagination per-page options configured for this resource.
 *
 * @return array
 */
public static $perPageOptions = [50, 100, 150];

/**
 * The pagination per-page options configured for this resource.
 *
 * @return array
 */
public static function perPageOptions()
{
    return [50, 100, 150];
}

/**
 * The number of resources to show per page via relationships.
 *
 * @var int
 */
public static $perPageViaRelationship = 10;

use Laravel\Nova\Actions\ExportAsCsv;
use Laravel\Nova\Http\Requests\NovaRequest;

/**
 * Get the actions available for the resource.
 *
 * @param  \Laravel\Nova\Http\Requests\NovaRequest  $request
 * @return array
 */
public function actions(NovaRequest $request)
{
    return [
        ExportAsCsv::make(),
    ];
}

return [
    ExportAsCsv::make()->nameable(),
];

return [
    ExportAsCsv::make()->withFormat(function ($model) {
        return [
            'ID' => $model->getKey(),
            'Name' => $model->name,
            'Email Address' => $model->email,
        ];
    }),
];

/**
 * The debounce amount (in seconds) to use when searching this resource.
 *
 * @var float
 */
public static $debounce = 0.5; // 0.5 seconds