Laravel / Eloquent - hasManyThrough - belongsToMany

Question

I try to create a messenger where users are able to join threads and therefore I have four tables:

users
    id - integer
    name - string

threads
    id - integer
    name - string
    created_at - dateTime
    updated_at - dateTime

participants
    user_id - integer
    threads_id - integer
    created_at - dateTime
    updated_at - dateTime
    deleted_at - dateTime

messages
    id - integer
    user_id - integer
    thread_id - integer
    text - string
    created_at - dateTime
    updated_at - dateTime
    deleted_at - dateTime

The User has:

threads(){
    return $this->belongsToMany(
        Thread::class,
        'participants',
        'user_id',
        'thread_id'
    )
    ->withTimestamps()
    ->withPivot('thread_id', 'user_id', 'deleted_at')
    ->orderBy('created_at', 'desc');
}

Now I try to get a relationship to the messages, only the messages which are after joining the thread should be visible:

public function messagesThroughThreads()
{
    $relation = $this->hasManyThrough(
        Message::class,
        $this->threads(),
        'user_id',
        'thread_id',
        'id',
        'id'
    )
        ->orderBy('updated_at', 'desc');

    return $relation;
}

actually, this is not working like that and I get the Models via:

public function messagesThroughThreads(bool $show_deleted = false)
{
    $messages = collect([]);

    foreach ($this->threads as $thread){
        if($thread->pivot->deleted_at){
            $m = $thread->messages_model()->whereBetween('messages.created_at', [$thread->pivot->deleted_at, $thread->pivot->created_at])->get();
        }else{
            $m = $thread->messages_model()->where('messages.created_at', '>=', $thread->pivot->created_at)->get();
        }
        $messages = $messages->merge($m->toArray());
    }

    return $messages->unique();
}

Any Idea how I could get a relationship instance with the same conditions?

Answer 1

There's no (native) relationship to access the messages directly.

Depending on your data it might be faster to get all messages and then remove some of them:

class Thread
{
    public function messages()
    {
        return $this->hasMany(Message::class);
    }
}

public function messagesThroughThreads(bool $show_deleted = false)
{
    $this->load('threads.messages');

    foreach ($this->threads as $thread) {
          $m = $thread->messages->where('created_at', '<=', $thread->pivot->deleted_at)
             ->where('created_at', '>=', $thread->pivot->created_at);
    }

You would be working on collections, so methods like whereBetween() aren't available.

Answer 2

I created a HasManyThrough relationship with unlimited levels: Repository on GitHub

After the installation, you can use it like this:

class User extends Model {
    use \Staudenmeir\EloquentHasManyDeep\HasRelationships;

    public function messagesThroughThreads() {
        return $this->hasManyDeep(Message::class, ['participants', Thread::class])
            ->whereColumn('messages.created_at', '>=', 'participants.created_at')
            ->where(function($query) {
                $query->whereNull('participants.deleted_at')
                    ->orWhereColumn('messages.created_at', '<=', 'participants.deleted_at');
            })->orderByDesc('messages.updated_at');
    }
}