How to use Library installed using composer in your custom module?

Question

I have installed the Authorize.net library in Magento using composer. Now, this library is available in the vendor directory but I don't have any idea how to use it in my custom module. The directory structure of Authorize.net in the vendor directory.

Answer 1

Namespace of that library should be available in the composer.json. I don't have Authorize.net, so below is an example from the Monolog:

"autoload": {
    "psr-4": {"Monolog\\": "src/Monolog"}
},

In this case you can use Logger class from src/Logger directory as: Monolog\Logger

Same should work for the Authorize.net