Capturing input from usb device in Linux

Question

So, after searching a little bit... have found the following way to capture the input from my USB QR code scanner.

import sys
pipe = open('/dev/input/event3', 'r')
while 1:
        for character in pipe.read():
                print(character)

It works, but I still have 2 questions regarding the method above.

I'm on a Raspberry device with Debian Wheezy and a GUI, and can confirm Question 2 happening on a GUI... don't know yet the output on a system without GUI

1. Any better way of doing it?
2. The method above, when I click right the script cancels and outputs all the entries that have been scanned, at once. Why is that?

UPDATE

I think I have miss interpreted the result for the code above, as it finally it outputs ASCII characters, so I ended up doing the following:

sys.stdin = open('/dev/tty')
a = raw_input('Scan: ')

Answer 1

Question 1 really depends on your QR scanner. I think you are lucky this works like this, since much of the time, usb devices have complex protocols to communicate with hosts. For example, with a mouse, how would you differentiate between clicks and mouse movement? You need some kind of data format to exchange.

Question 2 is probably because your method blocks at pipe.read(), waiting for input. Somehow, only the right click ends the read() function and allows the print to work out