laravel 模型观察器 observer 模型数据变化 触发观察器事件

1.生成观察器，会在Observers 文件夹下生成PurchaseOrderProductObserver观察器文件

    php artisan make:observer PurchaseOrderProductObserver -m  Models/PurchaseOrderProduct

    <?php

    namespace App\Observers;
    
    use App\Models\PurchaseOrderProduct;
    use App\Models\ShipmentProduct;
    use Illuminate\Support\Facades\Log;
    
    class PurchaseOrderProductObserver
    {
        /**
         * Handle the purchase order product "created" event.
         *
         * @param  \App\Models\PurchaseOrderProduct  $purchaseOrderProduct
         * @return void
         */
        public function created(PurchaseOrderProduct $purchaseOrderProduct)
        {
            //
        }
    
        /**
         * Handle the purchase order product "updated" event.
         *
         * @param  \App\Models\PurchaseOrderProduct  $purchaseOrderProduct
         * @return void
         */
        public function updated(PurchaseOrderProduct $purchaseOrderProduct)
        {
            //
            Log::info('observers', [$purchaseOrderProduct->price]);
            //isDirty 验证模型里某字段是否被改变
            if($purchaseOrderProduct->isDirty('price')){
                ShipmentProduct::where('purchase_order_product_id', '=', $purchaseOrderProduct->id)->update(array(
                    'supplier_price'=> $purchaseOrderProduct->price,
                ));
            } else {
                Log::info('observers', ['isDirty']);
            }
    
        }
    
        /**
         * Handle the purchase order product "deleted" event.
         *
         * @param  \App\Models\PurchaseOrderProduct  $purchaseOrderProduct
         * @return void
         */
        public function deleted(PurchaseOrderProduct $purchaseOrderProduct)
        {
            //
        }
    
        /**
         * Handle the purchase order product "restored" event.
         *
         * @param  \App\Models\PurchaseOrderProduct  $purchaseOrderProduct
         * @return void
         */
        public function restored(PurchaseOrderProduct $purchaseOrderProduct)
        {
            //
        }
    
        /**
         * Handle the purchase order product "force deleted" event.
         *
         * @param  \App\Models\PurchaseOrderProduct  $purchaseOrderProduct
         * @return void
         */
        public function forceDeleted(PurchaseOrderProduct $purchaseOrderProduct)
        {
            //
        }
    }

2.在Providers/AppServiceProvider 注册观察器

    <?php    
    namespace App\Providers;
    use App\Models\PurchaseOrderProduct;
    use App\Observers\PurchaseOrderProductObserver;
    use Illuminate\Support\Facades\DB;
    use Illuminate\Support\Facades\Schema;
    use Illuminate\Support\ServiceProvider;
    class AppServiceProvider extends ServiceProvider
    {
        /**
         * Register any application services.
         *
         * @return void
         */
        public function register()
        {
            //
            Schema::defaultStringLength(191);
            //左侧菜单
            view()->composer('erp.layout',function($view){
                $menus = \App\Models\Permission::with([
                    'childs'=>function($query){$query->with('icon')->orderBy('sort','desc');}
                    ,'icon'])->where('parent_id',0)->orderBy('sort','desc')->get();
                $view->with('menus',$menus);
            });
            // 如果要放入日志文件中
            DB::listen(
                function ($sql) {
                    foreach ($sql->bindings as $i => $binding) {
                        if ($binding instanceof \DateTime) {
                            $sql->bindings[$i] = $binding->format('\'Y-m-d H:i:s\'');
                        } else {
                            if (is_string($binding)) {
                                $sql->bindings[$i] = "'$binding'";
                            }
                        }
                    }
                    $query = str_replace(array('%', '?'), array('%%', '%s'), $sql->sql);
                    $query = vsprintf($query, $sql->bindings);
                    // Save the query to file
                    $logFile = fopen(
                        storage_path('logs' . DIRECTORY_SEPARATOR . date('Y-m-d') . '_query.log'),
                        'a+'
                    );
                    fwrite($logFile, date('Y-m-d H:i:s') . ': ' . $query . PHP_EOL);
                    fclose($logFile);
                }
            );
        }
        /**
         * Bootstrap any application services.
         *
         * @return void
         */
        public function boot()
        {
            //注入观察器
            PurchaseOrderProduct::observe(PurchaseOrderProductObserver::class);
        }
    }

3.两种方式 保存数据都可以触发 观察器的update 方法

    //第一种 update保存，必须加first    
    PurchaseOrderProduct::where('id', '=', 1)->first()->update(array(
                'label'=>'AAblocks1'
            ));
    //第二种 save保存
    $purchaseOrderProduct = PurchaseOrderProduct::find(1);
    $purchaseOrderProduct->label = 'AAblocks2';
    $purchaseOrderProduct->save();

4.laravel日志里可以看到打印的日志