How to retrieve a file (PDF) from a URL within SDK

Dear experts,

I'm calling an external web service in a customer extension for ByD. The response of this web service contains a URL to a PDF document.

Now the question would be how to read the PDF (base64 encoded) from that URL and store in ByD. Is there any get(URL) method available?

Any help is appreciated.

thanks in advance,

stephan