How to deploy relationship in pivot of three model in laravel?

I’m developing a role and permissions based on laravel framework.

I have 3 models :

Weblog
User
Permissions

This is pivot table

user_id , weblog_id , permission_id

Now, a user can have a weblog with permission id 1,2 and another weblog with permission 1,2,3,4

How can I deploy relationships? and how can I check user permissions when managing a weblog. (middleware and …)

Answer

With the fact that Permission are specific to Weblog

Say the pivot table is called permission_user_weblog

class User extends Model
{
    public function weblogs()
    {
        return $this->belongsToMany(Weblog::class, 'permission_user_weblog');
    }

    public function permissionsFor(int $weblogId)
    {
        $permissionIds = null;

        $this->weblogs()
            ->where('id', $weblogId)
            ->with('permissions')
            ->get()
            ->each(function($weblog) use(&$permissionIds) {
                $permissionIds = $weblog->permissions->pluck('id');             
            });

        return $permissionIds;
    }
}


class Weblog extends Model
{
    public function users()
    {
        return $this->belongsToMany(User::class, 'permission_user_weblog');
    }

    public function permissions()
    {
        return $this->belongsToMany(Permission::class, 'permission_user_weblog');
    }
}


class Permission extends Model
{
    public function weblogs()
    {
        return $this->belongsToMany(Weblog::class, 'permission_user_weblog');
    }
}

Then you can check anywhere for whether logged in user has specific permission for a specific weblog

public function update(Request $request, $weblogId)
{
    $user = auth()->user();
    $permissions = $user->permissionsFor($weblogId);

    //Check whether the logged in user has permission identified by id 1 or 4 for weblog
    $can = !! $permissions->intersect([1,4])->count();

    //Do rest of processing
}