Laravel View Composer 为每个视图复制 SQL 查询

Question

我需要在大多数视图中访问一些数据（用户详细信息）。我做了什么：

我创建了 ComposerServiceProvider

<?php

namespace App\Providers;

use Illuminate\Support\ServiceProvider;

class ComposerServiceProvider extends ServiceProvider
{
    /**
     * Bootstrap the application services.
     *
     * @return void
     */
    public function boot()
    {
        view()->composer(
            ['includes.header','profile'],
            'App\Http\ViewComposers\CustomerComposer'
        );

    }

    /**
     * Register the application services.
     *
     * @return void
     */
    public function register()
    {
        //
    }
}

已创建 CustomerComposer class

<?php

namespace App\Http\ViewComposers;

use Illuminate\Support\Facades\Auth;
use Illuminate\View\View;
use Modules\Customers\Entities\CustomerDetail;

class CustomerComposer
{
    public $customer = [];

    /**
     * Bind data to the view.
     *
     * @param  View  $view
     * @return void
     */
    public function compose(View $view)
    {
        $user = Auth::guard('customer');

        $this->customer = CustomerDetail::where('user_id',$user->id())->first();

        $view->with( 'customer', $this->customer );
    }
}

一切正常，但当我查看调试栏时，它显示每个视图都执行了相同的查询，因此例如，如果我定义 ['includes.header'，'profile'] 相同的 SQL 将是如果 ['includes.header','profile','something_else'] 执行了两次，依此类推...

在这种情况下查询是

select * from `customer_details` where `user_id` = '1' limit 1
select * from `customer_details` where `user_id` = '1' limit 1

如果我在

中提供通配符

view()->composer(
            ['*'],
            'App\Http\ViewComposers\CustomerComposer'
        );

它将生成 23 个查询！我在这里错过了什么？

Answer 1

根据 https://laravel.com/docs/5.5/views#view-composers 处的手册：

"View composers are callbacks or class methods that are called when a view is rendered. If you have data that you want to be bound to a view each time that view is rendered, a view composer can help you organize that logic into a single location."

（强调我的）

在这种情况下：

    view()->composer(
        ['includes.header','profile'],
        'App\Http\ViewComposers\CustomerComposer'
    );

您正在附加 includes.header 视图和 profile 视图，我猜其中包括 includes.header 视图。因此，由于 composer 在渲染视图时执行，因此它将执行两次，一次在渲染 profile 视图时执行，另一次在渲染 includes.header 视图时执行。

Answer 2

好的，我想我找到了解决方案。在 ComposerServiceProvider class:

/**
* Register the application services.
*
* @return void
*/
public function register()
{
    $this->app->singleton(\App\Http\ViewComposers\CustomerComposer::class);
}

那个吧。

在 Laravel 文档中

Registering A Singleton

Sometimes, you may wish to bind something into the container that should only be resolved once, and the same instance should be returned on subsequent calls into the container:

Answer 3

您可以在此处使用配置来解决视图撰写的多次查询运行问题。例如显示下面的代码。

public 函数撰写（查看 $view） {

if(!Config::has('composeVars')) 
{
    Config::set('composeVars') = [
      'users' => User::all();  
    ];
}

$view->with('*', Config::get('composeVars'));

}

Laravel View Composer 为每个视图复制 SQL 查询

Laravel View Composer duplicating SQL queries for every view

php

mysql

laravel

laravel-5

blade