Save e-mail attachment as a Case document

Hello,

We would like to have a functionnality allowing to save an e-mail attachment to a Case without leaving sugarcrm interface. Right now the only way to do this is manually by downloading the file and then upload it as a document.

What is the best way to implement this ? Using the API ? (https://support.sugarcrm.com/Documentation/Sugar_Developer/Sugar_Developer_Guide_7.9/Integration/Web_Services/v10/Exampl… )

Attachment in mail :

Goal (link attachment as a document to the case):

Thank you for your help