对集合进行分页，Laravel

Question

我尝试从 foreach 向每个用户添加一些新值，但因为我使用 get，现在我无法在响应上使用分页，但我还需要将该值添加到每个用户。有任何想法吗？

public function statistics()
    {
        $users = User::select(['id', 'name'])->get();
        foreach ($users as $key => $user) {
            $history = AnswerHistory::where('user_id', '=', $user->id)->get();
            $user->total_votes = count($history);
            $user->total_time = gmdate("H:i:s", ($history->sum('answer_time')));
        }

        return response()->json($users);
    }

Answer 1

默认情况下，你想要的在 Laravel 中是不可能的，但是你可以做一些事情。

解决方案一，您可以先返回分页器，然后修改集合。

    $users = User::select(['id', 'name'])->paginate(4)->toArray();

    $users['data'] = array_map(function ($user) {
            $history = AnswerHistory::where('user_id', '=', $user->id)->get();
            $user->total_votes = count($history);
            $user->total_time = gmdate("H:i:s", ($history->sum('answer_time')));
        return $user;
    }, $users['data']);

    return  $users;

解决方案二宏观方式。如果您愿意，可以将集合宏添加到服务提供者。这样您就可以在任何集合上调用 paginate()：请参阅 AppServiceProvider.php 以获取示例实现。

    public function boot()
    {
        Collection::macro('paginate', function ($perPage, $total = null, $page = null, $pageName = 'page') {
            $page = $page ?: LengthAwarePaginator::resolveCurrentPage($pageName);

            return new LengthAwarePaginator(
                $this->forPage($page, $perPage),
                $total ?: $this->count(),
                $perPage,
                $page,
                [
                    'path' => LengthAwarePaginator::resolveCurrentPath(),
                    'pageName' => $pageName,
                ]
            );
        });
    }

然后你的代码就会像这样

        $users = User::select(['id', 'name'])->get();
        foreach ($users as $key => $user) {
            $history = AnswerHistory::where('user_id', '=', $user->id)->get();
            $user->total_votes = count($history);
            $user->total_time = gmdate("H:i:s", ($history->sum('answer_time')));
        }

        return response()->json($users->paginate(4));

解决方案三子类方式。如果您想要一个与标准不同的“可分页”集合Illuminate\Support\Collection，请在您的应用程序中实现一个副本依赖文件顶部的语句Collection.php替换：use Illuminate\Support\Collectionuse App\Support\Collection

<?php

namespace App\Support;

use Illuminate\Pagination\LengthAwarePaginator;
use Illuminate\Support\Collection as BaseCollection;

class Collection extends BaseCollection
{
    public function paginate($perPage, $total = null, $page = null, $pageName = 'page')
    {
        $page = $page ?: LengthAwarePaginator::resolveCurrentPage($pageName);

        return new LengthAwarePaginator(
            $this->forPage($page, $perPage),
            $total ?: $this->count(),
            $perPage,
            $page,
            [
                'path' => LengthAwarePaginator::resolveCurrentPath(),
                'pageName' => $pageName,
            ]
        );
    }
}

你的代码将是这样的

// use Illuminate\Support\Collection
use App\Support\Collection;

        $users = User::select(['id', 'name'])->get();
        foreach ($users as $key => $user) {
            $history = AnswerHistory::where('user_id', '=', $user->id)->get();
            $user->total_votes = count($history);
            $user->total_time = gmdate("H:i:s", ($history->sum('answer_time')));
        }

        return response()->json((new Collection($users))->paginate(4);