为集合分页，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，现在我不能在响应中使用分页，但我还需要向每个用户添加该值。有什么想法吗？

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

根据您的 post，User 有很多 AnswerHistory。你可以在他们之间建立关系。

因此 total_votes 和 total_time 通过 withCount:

$users = User::withCount('answerHistories AS total_votes')
     ->withCount(['answerHistories AS total_time' => function($query) {
           $query->select(DB::raw("SUM(answer_time)"));
     }])->paginate(10);

并且可以通过getCollection获取分页数据，修改里面的数据：

$users->getCollection()->transform(function ($data) {
    $data->total_time = gmdate('H:i:s', $data->total_time);
    return $data;
});

Answer 2

您可以自己创建分页，请查看此 Laravel 文档 https://laravel.com/docs/7.x/pagination#manually-creating-a-paginator。我会建议使用 LengthAwarePaginator 这是数组

的一些代码示例

    // creating pagination
    $offset = max(0, ($page - 1) * $perPage);
    $resultArray = array_slice($result, $offset, $perPage);
    $paginator = new LengthAwarePaginator($resultArray, count($result), $perPage, $page);
    $paginator->setPath(url()->current());
    $paginator->appends(['per_page' => $perPage]);

    return response()->json([
        'message' => 'Success',
        'data'    => $paginator
    ]);

但我认为你的案例有更好的 "good" 解决方案，你可以加载 AnswerHistory 与 hasMany Laravel 关系和 with 函数。

Answer 3

默认情况下 laravel 无法满足您的需求，但您可以做一些事情。

解决方法一可以先return分页器再修改集合

    $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;

解决方法二宏方式。如果您愿意，可以将 Collection 宏添加到服务提供者。这样你就可以在任何集合上调用 paginate() ：有关示例实施，请参阅 AppServiceProvider.php。

    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));

解决方法三子类方式。如果您想要一个不同于标准 Illuminate\Support\Collection 的 "pageable" 集合，请在您的应用程序中实现 Collection.php 的副本，并简单地替换您依赖项顶部的 use Illuminate\Support\Collection 语句use App\Support\Collection:

的文件

<?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,
            ]
        );
    }
}

你的代码会像这样

// 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);

为集合分页，Laravel

Paginate for a collection, Laravel

laravel

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