一、创建模型

创建点赞模型

php artisan make:model Vote -m

修改生成的 database/migrations/create_votes_table.php

public function up()
{
    Schema::create('votes', function (Blueprint $table) {
        $table->increments('id');
        $table->unsignedInteger('user_id')->index();
        $table->unsignedInteger('answer_id')->index();
        $table->timestamps();
    });
}

执行数据迁移

php artisan migrate

修改 app/User.php

public function votes()
{
    return $this->belongsToMany(Answer::class, 'votes')->withTimestamps();
}

public function voteFor($answer)
{
    return $this->votes()->toggle($answer);
}

public function hasVotedFor($answer)
{
    return !! $this->votes()->where('answer_id', $answer)->count();
}

修改 app/Repositories/AnswerRepository.php

public function byId($id)
{
    return Answer::find($id);
}

二、创建控制

php artisan make:controller VotesController

修改 app/Http/Controllers/VotesController.php

namespace App\Http\Controllers;

use App\Repositories\AnswerRepository;
use Auth;
use Illuminate\Http\Request;

class VotesController extends Controller
{
    protected $answer;

    public function __construct(AnswerRepository $answer)
    {
        $this->answer = $answer;
    }

    public function index(Request $request)
    {
        if(user('api')->hasVotedFor($request->get('answer'))){
            $voted = true;
        }else{
            $voted = false;
        }
        return response()->json(['voted'=>$voted]);
    }

    public function vote()
    {
        $answer = $this->answer->byId(request('answer'));
        $userToVote = user('api')->voteFor(request('answer'));
        if(count($userToVote['attached']) > 0){
            $answer->increment('votes_count');
            $voted = true;
        }else{
            $answer->decrement('votes_count');
            $voted = false;
        }
        return response()->json(['voted'=>$voted]);
    }
}

修改 routes/api.php

Route::post('/answer/voter', 'VotesController@index')->middleware('auth:api');
Route::post('/answer/vote', 'VotesController@vote')->middleware('auth:api');

三、创建视图

新建 resources/assets/js/components/UserVoteButton.vue

注册组件：修改 resources/assets/js/app.js

Vue.component('user-vote-button', require('./components/UserVoteButton.vue'));

执行 gulp

gulp

修改 resources/views/questions/show.blade.php

访问：http://127.0.0.1:8000/questions/id，id 为问题 ID 

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