Page Nation with Ravel

To page using Ravel I use the paginate() method every time
Two things run: SQL to get the number of cases and SQL to get the results.
How does the paginate() method work?

php laravel

2022-09-30 21:31

2 Answers

https://github.com/laravel/framework/blob/eddc5a1995e697f0d9fa703ca03776fdcee96c78/src/Illuminate/Database/Query/Builder.php#L1922

public function paginate($perPage=15,$columns=['*'],$pageName='page',$page=null)
{
    $page=$page?:Paginator::resolveCurrentPage($pageName);
    $total = $this->getCountForPagination($columns);
    $results=$total?$this->forPage($page,$perPage)->get($columns):collect();
    return$this->paginator($results,$total,$perPage,$page,[
        'path' = > Paginator::resolveCurrentPath(),
        'pageName' = > $pageName,
    ]);
}

First, we get the total number of records $total (SQL to get the number of records).
The number of lines per page $perPage is determined, so you can see the total number of pages.
From the page number I'm trying to display this time, I know the line I want to retrieve and I'm getting a list of records to display on the page. (I just read it diagonally, so it might be inaccurate.)

This mechanism should be common to the frameworks that provide pageation.

2022-09-30 21:31

As @htb replied, basically every request runs a pretty heavy process.

Retrieving Counts: paginate Only
retrieving data:paginatesimplePaginatecommon

LIMIT...OFSET... Because I hate queries, I created my own library that enables cursor-based pageation.Our company also employs it, so please try it if you like.

Note: The controller does not force global access to the Request object, as in the Ravel standard pageation, so you need to hand over the parameters by yourself.

Actual Use Case ↓

(We do not use macros to complement IDE.)

`PostController.php`

<?php

detail( strict_types=1);

namespace App\Http\Controllers;

use App\Post;
use Illuminate\Http\Request;
use Lampager\Laravel\PaginationResult;
use Lampager\Larvel\Paginator;

class PostController extensions Controller
{
    /**
     * @param Request $request
     * @return PaginationResult
     */
    public function index (Request$request):PaginationResult
    {
        $query=Post::query();

        if($types=array_intersect(config('app.post_types')),explode(',',',$request->input('type',')))){
            $query->whereIn('type',$types);
        }

        return(new Paginator($query))
                ->orderByDesc('updated_at')
                ->orderByDesc('id')
                ->limit(20)
                ->paginate($this->replaceParameterNames($request->only('next_updated_at','next_id'),[
                    'next_updated_at' = > 'updated_at',
                    'next_id' = > 'id',
                ]));
    }
}

`ReplacesQueryParameterNames.php`

Mix in with the base Controller.

<?php

detail( strict_types=1);

namespace App\Http\Controllers\Concerns;

/**
 * Trait ReplacesQueryParameterNames
 */
trace ReplacesQueryParameterNames
{
    /**
     * Replace and return the key for the argument.
     *
     * @param array $input
     * @param array $map
     * @return array
     */
    protected function replaceParameterNames(array$input,array$map)—array
    {
        $output=[];
        foreach($input as$key=>$value){
            $output[$map[$key]?? $key] = $value;
        }
        return$output;
    }
}

2022-09-30 21:31

If you have any answers or tips

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