Laravel Polymorphic Relations Has Many Through

Question

I have a Subscriber model

// Subscriber Model  id user_id subscribable_id subscribable_type  public function user() {     return $this->belongsTo('App\User'); }  public function subscribable() {     return $this->morphTo(); } 

And a Topic model

// Topic Model  public function subscribers() {     return $this->morphMany('App\Subscriber', 'subscribable'); } 

And I want to get all users through Subscriber model, to notify them like

Notification::send($topic->users, new Notification($topic));

// Topic Model   public function users() {     return $this->hasManyThrough('App\User', 'App\Subscriber'); } 

Any ideas?

Answer 1

// Topic Model  public function users() {     return $this->hasManyThrough('App\User', 'App\Subscriber', 'subscribable_id')         ->where(             'subscribable_type',              array_search(static::class, Relation::morphMap()) ?: static::class         ); } 

Polymorphic hasManyThrough relationships are the same as any others, but with an added constraint on the subscribable_type, which can be retrieved from the Relation::morphMap() array, or by using the class name directly.

Answer 2

In addition to Matt's approach, the following code also could be another solution:

//Topic Model public function users() {     return $this->belongsToMany(User::class, 'subscribers', 'subscribale_id', 'user_id')         ->where('subscribale_type', static::class); } 

In this way Subscriber treated as a pivot table and second argument is table name for pivot.

The third argument is the foreign key name of the model on which you are defining the relationship, while the fourth argument is the foreign key name of the model that you are joining to. Read more here.

Consider the where clause after belongsToMany to filter only the current model.