You definitely could, and it would be much easier to write the HTTP client code on a Raspberry Pi than it is on the Arduino! If you look at the Arduino code (h

You definitely could, and it would be much easier to write the HTTP client code on a Raspberry Pi than it is on the Arduino! If you look at the Arduino code (https://github.com/freerange/printer/blob/master/printer.ino https://github.com/freerange/printer/blob/master/printer.ino), all it does is download a stream of bytes, doing some very rudimentary validation (Content-length), and then sending the bytes out on a serial port.