I want to use Checkout SDK with Yii2 but since this library does not support PSR-4 standards (namespaces) I am having trouble to integrate it. How can I use this library for my purpose?
EDIT
As suggested I tried to use class as
$sale = new \Twocheckout_Sale();
but still I am unable to make it work.
When the class does not have namespace it means it's in the root namespace.
Option 1:
use Twocheckout;
...
Twocheckout::format('json');
Option 2:
\Twocheckout::format('json');
For example, PHPExcel extension also doesn't have namespaces, similar question was answered on official forum.
Related questions:
Importing class without namespace to namespaced class
How to use "root" namespace of php?
Official PHP documentation:
http://php.net/manual/en/language.namespaces.fallback.php
Update:
But PHPExcel has own autoloader, while 2Checkout does not. All classes are included by requiring one main abstract class. It's even mentioned in official readme:
require_once("/path/to/2checkout-php/lib/Twocheckout.php");
So you need to manually include it before using library classes. It can be done with help of alias to avoid writing full path.
use Yii;
...
$path = Yii::getAlias("@vendor/2checkout/2checkout-php/lib/Twocheckout.php");
require_once($path);
$sale = new \Twocheckout_Sale();
For usage in one place it's OK, but if it will be used in many places of application, it's better to require it in entry script index.php:
require(__DIR__ . '/../../vendor/autoload.php');
require(__DIR__ . '/../../vendor/2checkout/2checkout-php/lib/Twocheckout.php');
require(__DIR__ . '/../../vendor/yiisoft/yii2/Yii.php');
require(__DIR__ . '/../../common/config/bootstrap.php');
require(__DIR__ . '/../config/bootstrap.php');
I also recommend to read tips in official documentatiton about using downloaded libraries, there are more options you can use depending on the specific library.