66.热门话题

TDD 构建 Laravel 论坛笔记 /

本系列文章为laracasts.com 的系列视频教程——Let's Build A Forum with Laravel and TDD 的学习笔记。若喜欢该系列视频，可去该网站订阅后下载该系列视频， 支持正版 ；

视频源码地址：github.com/laracasts/Lets-Build-a-...；

本项目为一个 forum（论坛）项目，与本站的第二本实战教程《Laravel 教程 - Web 开发实战进阶》类似，可互相参照。

本节说明

对应视频教程第 66 小节：Trending Threads With Redis

本节内容

本节我们使用 Redis 来开发热门话题功能。首先我们安装 Redis：

$ composer require predis/predis

接着我们更改话题列表视图：
forum\resources\views\threads\index.blade.php

@extends('layouts.app')

@section('content')
    <div class="container">
        <div class="row">
            <div class="col-md-8">
                @include ('threads._list')

                {{ $threads->render() }}
            </div>

            <div class="col-md-4">
                <div class="panel panel-default">
                    <div class="panel-heading">
                        Trending Threads
                    </div>

                    <div class="panel-body">
                        something here.
                    </div>
                </div>
            </div>
        </div>
    </div>
@endsection

刷新页面：
file
接下来新建测试：
forum\tests\Feature\TrendingThreadsTest.php

<?php

namespace Tests\Feature;

use Illuminate\Support\Facades\Redis;
use Tests\TestCase;
use Illuminate\Foundation\Testing\DatabaseMigrations;

class TrendingThreadsTest extends TestCase
{
    use DatabaseMigrations;

    public function setUp()
    {
        parent::setUp();

        Redis::del('trending_threads');
    }

    /** @test */
    public function it_increments_a_thread_score_each_time_it_is_read()
    {
         $this->assertEmpty(Redis::zrevrange('trending_threads',0,-1));

        $thread = create('App\Thread');

        $this->call('GET',$thread->path());

        $trending = Redis::zrevrange('trending_threads',0,-1);

        $this->assertCount(1,$trending);

        $this->assertEquals($thread->title,json_decode($trending[0])->title);
    }
}

由于我们使用了 Redis 系统，所以我们在运行测试之前需要清除缓存。我们建立了第一个测试：当未访问话题详情页面时，缓存为空；当访问了话题详情页面，缓存中会存在一条记录，同时，该记录的title键对应的值即为该话题的值。我们接下来修改控制器，访问详情页时存入缓存：
forum\app\Http\Controllers\ThreadsController.php

<?php

namespace App\Http\Controllers;

use Illuminate\Support\Facades\Redis;
.
.
class ThreadsController extends Controller
{
    .
    .
    public function show($channel,Thread $thread)
    {
        if(auth()->check()){
            auth()->user()->read($thread);
        }

        Redis::zincrby('trending_threads',1,json_encode([
            'title' => $thread->title,
            'path' => $thread->path()
        ]));

        return view('threads.show',compact('thread'));
    }
    .
    .
}

运行测试：
file
接下来我们在页面显示热门话题。首先我们在控制器中取出分数最高的 5 个话题：
forum\app\Http\Controllers\ThreadsController.php

    .
    .
    public function index(Channel $channel,ThreadsFilters $filters)
    {
        $threads = $this->getThreads($channel, $filters);

        if(request()->wantsJson()){
            return $threads;
        }

        $trending = array_map('json_decode',Redis::zrevrange('trending_threads',0,4));

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

然后我们再显示在话题列表页：
forum\resources\views\threads\index.blade.php

    .
    .
    <div class="col-md-4">
                @if(count($trending))
                    <div class="panel panel-default">
                        <div class="panel-heading">
                            Trending Threads
                        </div>

                        <div class="panel-body">
                            <ul class="list-group">
                                @foreach($trending as $thread)
                                    <li class="list-group-item">
                                        <a href="{{ url($thread->path) }}">
                                            {{ $thread->title }}
                                        </a>
                                    </li>
                                @endforeach
                            </ul>
                        </div>
                    </div>
                @endif
            </div>
    .
    .

查看效果：
file