Magento – Get product collection in Magento2 root file

Inject class \Magento\Framework\Stdlib\DateTime\DateTime $stdlibDateTime
For example your collection have field from_date and to_date

    // init current time now
    $currentTime = $this->stdlibDateTime->date();

    // Filter datetime
    $collections = $this->getResourceCollection()
        ->addFieldToFilter('from_date', ['lteq' => $currentTime])
        ->addFieldToFilter('to_date', ['gteq' => $currentTime])
        ->setOrder('sort_order', 'ASC')
        ->getData();

The authentic and recommended way to fetch product collection is to use API interface

Magento\Catalog\Api\ProductRepositoryInterface

method

getList(\Magento\Framework\Api\SearchCriteriaInterface $searchCriteria)

for this you need to build the search criteria first

Your class should include below classes -

use Magento\Catalog\Api\ProductRepositoryInterface;
use Magento\Framework\Api\SearchCriteriaBuilder;
use Magento\Catalog\Model\Product\Type;
use Magento\Catalog\Model\Product\Visibility;
use Magento\Catalog\Model\Product\Attribute\Source\Status;

Class constructor should be -

/** @var ProductRepositoryInterface  */
protected $productRepository;

/** @var SearchCriteriaBuilder  */
protected $searchCriteriaBuilder;

/** @var Visibility  */
protected $productVisibility;

/** @var Status  */
protected $productStatus;

/**
 * Edit constructor.
 * @param ProductRepositoryInterface $productRepositoryInterface
 * @param SearchCriteriaBuilder $searchCriteriaBuilder
 * @param Visibility $visibility
 * @param Status $status
 */
public function __construct(
    ProductRepositoryInterface $productRepositoryInterface,
    SearchCriteriaBuilder $searchCriteriaBuilder,
    Visibility $visibility,
    Status $status
) {
    $this->productRepository = $productRepositoryInterface;
    $this->searchCriteriaBuilder = $searchCriteriaBuilder;
    $this->productVisibility = $visibility;
    $this->productStatus = $status;
}

Get list method should be -

/**
 * @return array
 */
public function getProductList()
{
    $searchCriteriaBuilder = $this->searchCriteriaBuilder
        ->addFilter('type_id', Type::TYPE_SIMPLE, 'eq')
        ->addFilter('status', $this->productStatus->getVisibleStatusIds(), 'in')
        ->addFilter('visibility', $this->productVisibility->getVisibleInCatalogIds(), 'in')
        ->create();

    $productList = $this->productRepository->getList($searchCriteriaBuilder);
    //echo $productList->getTotalCount();
    $items = $productList->getItems();

    return $items;
}