How to get tag slugs of a new discussion?

aley

When creating a new discussion, I would like to catch the slugs of the attached tags using the DiscussionWillBeSaved event.

Normally I do this, which returns the expected result on an existing discussion

public function whenDiscussionWillBeSaved(DiscussionWillBeSaved $event)
{
       foreach($event->discussion->tags->all() as $tag) {
           $tags[] = $tag->slug;
       }
}

clarkwinkelmann

aley what is your issue ?

It seems the event is correctly triggered when a new discussion is created https://github.com/flarum/core/blob/v0.1.0-beta.7/src/Core/Command/StartDiscussionHandler.php#L73

You can know if the discussion already exists by reading $event->discussion->exists

There's also a DiscussionWasStarted event available (I believe that one is triggered after the save).

aley

clarkwinkelmann the event is triggered correctly, true, but I can't fetch the tags. As I see, the tag ids are passed via $event->data. So I probably have to collect the ids and fetch the tag slugs from the database.

I don't like to use DiscussionWasStarted since I perform some checks on the content before the discussion gets saved.

clarkwinkelmann

aley oh right.

Actually, tags are only persisted to the database at the same time as the discussion is saved, see https://github.com/flarum/flarum-ext-tags/blob/f40a053f8a5196e6aa354c20d011364982f7dc4a/src/Listener/SaveTagsToDatabase.php#L119

So to access the tags you need to either read the raw request data (which might not have been validated properly by the tags extension at this point) or read it after the save. You could use a second event (but I understand this might be impractical) or register an "after save" method with $discussion->afterSave().

I suppose if you need to validate something while knowing the list of tags you will have to read the incoming request data. Keep in mind that any value and any format might be passed and not yet be validated by the tags listener.

You could also change the priority of your listener to make sure it runs before or after the tags extension.

aley

Alright, thanks a lot!