filtering a paginated eloquent collection

Question

I am trying to filter a paginated eloquent collection, but whenever I use any of the collection methods, I lose the pagination.

$models = User::orderBy('first_name','asc')->paginate(20);

$models = $models->each(function($model) use ($filters) {
    if(!is_null($filters['type'])) {
        if($model->type == $filters['type'])
            return $model;
    }

    if(!is_null($filters['state_id'])) {
        if($model->profile->state_id == $filters['state_id'])
            return $model;
    }

    if(!is_null($filters['city_id'])) {
        if($model->profile->city_id == $filters['city_id'])
            return $model;
    }
});

return $models;

I am working with Laravel 4.2, is there any way to persist the pagination?

Answer 1

An answer to the titular question, which is possible in Laravel 5.2+:

How to filter the underlying collection of a Paginator without losing the Paginator object?

You can eject, modify and inject the collection as follows:

$someFilter = 5;
$collection = $paginator->getCollection();
$filteredCollection = $collection->filter(function($model) use ($someFilter) {
  return $model->id == $someFilter;
});
$paginator->setCollection($filteredCollection);

The Paginator is built on an underlying collection, but indeed when you use any of the inherited Collection methods they return the underlying collection and not the full Paginator object: collection methods return collections for chaining together collection calls.

Answer 2

Expanding on mininoz's answer with your specific case:

//Start with creating your object, which will be used to query the database

$queryUser = User::query();

//Add sorting

$queryUser->orderBy('first_name','asc');

//Add Conditions

if(!is_null($filters['type'])) {
    $queryUser->where('type','=',$filters['type']);
}

if(!is_null($filters['state_id'])) {
    $queryUser->whereHas('profile',function($q) use ($filters){
        return $q->where('state_id','=',$filters['state_id']);
    });
}

if(!is_null($filters['city_id'])) {
    $queryUser->whereHas('profile',function($q) use ($filters){
        return $q->where('city_id','=',$filters['city_id']);
    });
}

//Fetch list of results

$result = $queryUser->paginate(20);

By applying the proper conditions to your SQL query, you are limiting the amount of information that comes back to your PHP script, and hence speeding up the process.

Source: http://laravel.com/docs/4.2/eloquent#querying-relations