在使用laravel开发后端接口时，需要分页。但是paginate（）无法传递当前页面值，只能传一个展示条数；

查看paginator

Illuminate\Pagination;
class Paginator extends AbstractPaginator {}

可以看到继承AbstractPaginator

trait MyPage
{
    protected function page($data = [],$perPage = 10,$page = 1)
    {
        $offset = ($page * $perPage) - $perPage;
        $res = new LengthAwarePaginator(array_slice($data, $offset, $perPage, true), count($data), $perPage, $page);
        $res = $res->toArray();
        return [
            //使用array_values去掉索引数组key
            'data'=>array_values($res['data']),
            'total'=>$res['total']
        ];
    }
}

创建一个trait直接使用LengthAwarePaginator
可以传入

$perPage //展示条数
$page //页码

可以看到数据如下

array:2 [
  "data" => array:1 [
    0 => array:5 [
      "id" => 2
      "name" => "test"
    ]
  ]
  "total" => 2
]

此数据就可供前端使用了
在控制器中

class TestController extends Controller
{
    use MyPage;
    
    省略....
    public function index(Request $request){
    ...
    	$data = User::get()->toArray();
    	$res = $this->page($data,$perPage,$page);
    	...
    }

之后发现这么写挺蠢的，拿到数据再做分页，有问题;

所以更新

	use Illuminate\Database\Eloquent\Builder;
	//把分页应该放到查询里
    public function paginate(Builder $query, $page = 1, $perpage = 10, $load = ''){
        $skip = ($page - 1)*$perpage;
        $count = $query->count('*');
        $totalPage = $count == 0 ? 0 : (int)ceil($count / $perpage);
        if($load === ''){
            $list = $query->skip($skip)->take($perpage)->get()->toArray();
        }else{
            $list = $query->skip($skip)->take($perpage)->get()->load($load)->toArray();
        }
        return [
            'data'=>$list,
            'total'=>$count,
            'totalPage'=>$totalPage,
        ];
    }

控制器里的代码还是差不多

	public function list(Request $req){
		...
		$data = $this->paginate(User::select('*'),$req->page1,$req->perpage);
		...
	}

Laravel实现适用于API的分页查询

Laravel自带分页查询方法里有一些多余的数据，并不完美适用于我们用来做API的查询。本文旨在通过重写 paginate 解决分页查询针对API接口的的灵活性和适用性。

新建BaseModel.php文件,代码如下。

<?php

namespace App\Http\Model;

use Illuminate\Database\Eloquent\Model;
use Illuminate\Pagination\Paginator;

class BaseModel extends Model{
    public $timestamps = false;
    //重写分页方法，使其更加匹配API的规范
    //考虑到性能问题，通常$columns我们不以*号为值。可传入需要查询的字段替代。这里只做演示。无此要求
    public function paginate($perPage = null, $columns = ['*'], $page = null, $pageName = 'page'){
        $page = $page ?: Paginator::resolveCurrentPage($pageName);

        $perPage = $perPage ?: $this->model->getPerPage();

        $results = ($total = $this->toBase()->getCountForPagination())
            ? $this->forPage($page, $perPage)->get($columns)
            : $this->model->newCollection();
        $pages = ceil($total / $perPage);
        $result = ['total'=>$total,'current_page'=>$page,'page_size'=>$perPage,'pages'=>$pages,'list'=>$results];
        return $result;
    }
}

然后在业务模型继承此类即可，范例如下

<?php

namespace App\Http\Model;

class MsgBoard extends BaseModel{
    protected $table = 'msg_board';

    public function getMsgPageList($page,$pageSize){
        return $this->paginate($pageSize, ['*'], $page, 'page');
    }
}

然后在控制器当中屌用即可。范例如下

$page = $request->input('page',1);
$pageSize = $request->input('pageSize',12);
$msgList = $mMsgBoard->getMsgPageList($page,$pageSize);