方法Illuminate \ Database \ Query \ Builder :: filter不存在 [英] Method Illuminate\Database\Query\Builder::filter does not exist

问题描述

我正在按照一个教程编写两个用于过滤论坛应用程序中的线程的类.我在此在线得到此错误
$ threads = Thread :: latest()-> filter($ filters); (在threadscontroller中)

I am following a tutorial to write 2 classes for filtering threads in a forum application.I got this error in line
$threads = Thread::latest()->filter($filters); (in threadscontroller)

方法Illuminate \ Database \ Query \ Builder :: filter不存在.

Method Illuminate\Database\Query\Builder::filter does not exist.

带有索引方法的ThreadsController:

ThreadsController with index method:

<?php

namespace App\Http\Controllers;

use App\Thread;
use App\Channel;
use App\Filters\ThreadFilters;

use Illuminate\Http\Request;

class ThreadsController extends Controller
{

    public function __construct(){

        $this->middleware('auth')->only('store','create');

    }
    /**
     * Display a listing of the resource.
     *
     * @return \Illuminate\Http\Response
     */
    public function index(Channel $channel,ThreadFilters $filters)  
    {

$threads = Thread::latest()->filter($filters);  

if($channel->exist){
    $threads->where('channel_id',$channel->id);
}

$threads = $threads->get();

return view('threads.index',compact('threads'));



    }

这是抽象类Filters:

This is the abstract class Filters:

<?php

namespace App\Filters;
use Illuminate\Http\Request;

abstract class Filters{

protected $request;
protected $builder;

protected $filters = [];

    public function __construct(Request $request){
        $this->request = $request;



    }

    public function apply($builder){
        $this->builder = $builder;

        foreach($this->getFilters() as $filter=>$value){   //filter by,value yunus mesela.
if(method_exist($this,$filter)){    
    $this->$filter($value);  
}

        }

        return $this->builder;

    }


    public function getFilters(){

        return $this->request->intersect($this->filters); 
    } 

}

这里ThreadFilters.php扩展了过滤器类:

Here ThreadFilters.php which extends filters class:

<?php

namespace App\Filters;

use App\User;

use Illuminate\Http\Request;


class ThreadFilters extends Filters
{
protected $filters =['by'];        

protected function by($username){
    $user = User::where('name',$username)->firstorFail();

    return $this->builder->where('user_id',$user->id);



}

}

如果我对所有内容都进行了最新更改，则会收到以下错误消息: 类型错误:传递给Illuminate \ Support \ Collection :: filter()的参数1必须是可调用的或为null，已给定对象，在

If i change latest to all,i get this error: Type error: Argument 1 passed to Illuminate\Support\Collection::filter() must be callable or null, object given, called in

还有谁能解释我在这些课程中$ builder在做什么?

Also can anyone explain me what is $builder doing in those classes ?

推荐答案

latest()是修饰符快捷方式，等效于orderBy('created_at', 'desc').它所做的只是向查询添加ORDER BY约束.

latest() is a modifier shortcut, equivalent to orderBy('created_at', 'desc'). All it does is add the ORDER BY constraint to the query.

filter()是Collection类上的方法.该方法在查询生成器中不存在，因此，您将收到找不到方法"错误.

filter() is a method on the Collection class. That method does not exist in the query builder, hence the "method not found" error you're receiving.

似乎没有将过滤器类与结果Collection一起使用.而是，它向您的原始查询添加条件.尝试像这样实现它:

It does not appear that your filter class should be used with the resulting Collection. Rather, it adds conditionals to your original query. Try implementing it like this:

// Remove the filters() method here.
$threads = Thread::latest();  

if ($channel->exist) {
    $threads->where('channel_id', $channel->id);
}

// Pass your query builder instance to the Filters' apply() method.
$filters->apply($threads);

// Perform the query and fetch results.
$threads = $threads->get();

此外，对于将来的问题，包括您正在尝试/遵循的教程，可以为那些帮助您的人提供有益的背景. :)

Also, for future questions, including the tutorial you're attempting/following can provide beneficial context to those helping you. :)

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