pp/Library/app/Models/User.php

<?php

namespace App\Models;

use Cviebrock\EloquentSluggable\Sluggable;
use Illuminate\Foundation\Auth\User as Authenticatable;
use Illuminate\Notifications\Notifiable;
use Illuminate\Support\Facades\Storage;

class User extends Authenticatable
{
    use Notifiable, Sluggable;

    /**
     * The attributes that are mass assignable.
     *
     * @var array
     */
    protected $fillable = [
        'avatar', 'avatar_rating', 'user_verified_at', 'name', 'email', 'password',
    ];

    /**
     * The attributes that should be hidden for arrays.
     *
     * @var array
     */
    protected $hidden = [
        'password', 'remember_token',
    ];

    /**
     * The attributes that should be cast to native types.
     *
     * @var array
     */
    protected $casts = [
        'email_verified_at' => 'datetime',
    ];

    public function books()
    {
        return $this->hasMany(Book::class);
    }

    public function comments()
    {
        return $this->hasMany(Comment::class);
    }

    public function getRouteKeyName()
    {
        return 'slug';
    }

    public function sluggable()
    {
        return [
            'slug' => [
                'source' => 'name'
            ]
        ];
    }

    public function UserAvatar(){
        if(is_null($this->avatar)){
            $url = asset('images/default-avatar.jpg');
        }
        else {
            $url = url(Storage::url($this->avatar));
        }
        return $url;
    }
}