laravel中消息通知功能

以laravel5.5为例子，这个功能laravel自带的有：

1.生成表文件的migration文件，再migrate一下在数据库里生成表.命令为:php artisan notifications:table    ||    php artisan migrate

2.在user表里增加一个notification_count 字段可以为null,

3.因为没有这个类，所以要生成个通知类：php artisan make:notification TopicReplied

4.类内注入$reply实例：

<?php

namespace App\Notifications;

use Illuminate\Bus\Queueable;
use Illuminate\Notifications\Notification;
use Illuminate\Contracts\Queue\ShouldQueue;
use Illuminate\Notifications\Messages\MailMessage;
use App\Models\Reply;

class TopicReplied extends Notification
{
    use Queueable;

    public $reply;

    public function __construct(Reply $reply)
    {
        // 注入回复实体，方便 toDatabase 方法中的使用
        $this->reply = $reply;
    }

    public function via($notifiable)
    {
        // 开启通知的频道
        return ['database'];
    }

    public function toDatabase($notifiable)
    {
        $topic = $this->reply->topic;
        $link =  $topic->link(['#reply' . $this->reply->id]);

        // 存入数据库里的数据
        return [
            'reply_id' => $this->reply->id,
            'reply_content' => $this->reply->content,
            'user_id' => $this->reply->user->id,
            'user_name' => $this->reply->user->name,
            'user_avatar' => $this->reply->user->avatar,
            'topic_link' => $link,
            'topic_id' => $topic->id,
            'topic_title' => $topic->title,
        ];
    }
}

　　4.触发通知 ：在人家刚回复保存时触 发；

use App\Notifications\TopicReplied;

class ReplyObserver
{
    public function created(Reply $reply)
    {
        $topic = $reply->topic;
        $topic->increment('reply_count', 1);

        // 通知作者话题被回复了
        $topic->user->notify(new TopicReplied($reply));
    }

}

　　5.当有多个通知时，自动给用户里的通知数量+1

use Auth;

class User extends Authenticatable
{
    use Notifiable {
        notify as protected laravelNotify;
    }
    public function notify($instance)
    {
        // 如果要通知的人是当前用户，就不必通知了！
        if ($this->id == Auth::id()) {
            return;
        }
        $this->increment('notification_count');
        $this->laravelNotify($instance);
    }
}