update-product.php

<?php
public function updateProduct($productId ) {
	$api = $this->api;
	$payload = $api->request()->post(); 

	$product = new ProductObject( (int) $productId );
	if(!Validate::isLoadedObject($product)) {
		$api->response->setStatus(404);
		return $api->response([
			'success' => false,
			'message' => 'Product was not found'
		]);
	}

	if (ArrayUtils::has($payload, 'name')) {
		$name = ArrayUtils::get($payload, 'name');
		if ( !Validate::isGenericName($name) ) {
			return $api->response([
				'success' => false,
				'message' => 'Enter a valid product name'
			]);
		}

		$product->name = $name;
	}

	if (ArrayUtils::has($payload, 'description')) {
		$description = ArrayUtils::get($payload, 'description');
		if (!Validate::isCleanHtml($description)) {
			return $api->response([
				'success' => false,
				'message' => 'Enter a valid description of the product'
			]);
		}

		$product->description = $description;
	}

	if (ArrayUtils::has($payload, 'description')) {
		$price = ArrayUtils::get($payload, 'price');
		if (!Validate::isPrice($price)) {
			return $api->response([
				'success' => false,
				'message' => 'Enter a valid price of the product'
			]);
		}

		$product->price = $price;
	}

	if (ArrayUtils::has($payload, 'category_id')) {
		$category_id = ArrayUtils::get($payload, 'category_id');
		if(!Validate::isInt($category_id)) {
			return $api->response([
				'success' => false,
				'message' => 'Enter a valid category ID of the product'
			]);
		}

		$category = new CategoryObject( (int) $category_id );
		if (!Validate::isLoadedObject($category)) {
			return $api->response([
				'success' => false,
				'message' => 'The category ID (' . $category_id . ') does not exist'
			]);
		}

		$product->category_id = $category->id;
	}

	return $api->response([
		'success' => false,
		'message' => 'Unable to update product'
	]);

	$ok = $product->save();
	// or product->update()

	if (!$ok) {
		return $api->response([
			'success' => false,
			'message' => 'Unable to update product'
		]);
	}

	return $api->response([
		'success' => true,
		'message' => 'Product updated successfully'
	]);
}