shorten_dropbox_url.py

import time
import threading
import pyperclip
import bitly

# fill you auth
bitlyAPI = bitly.Api(login='', apikey='')

def get_short_url(url):
    return bitlyAPI.shorten(url, {'history':1})

def is_url_but_not_bitly(url):
    if url.startswith("https://www.dropbox.com/s/") and not "bit.ly" in url:
        return True
    return False

def print_to_stdout(clipboard_content):
    pyperclip.copy(get_short_url(clipboard_content))

# http://stackoverflow.com/questions/14685999/trigger-an-event-when-clipboard-content-changes
class ClipboardWatcher(threading.Thread):
    def __init__(self, predicate, callback, pause=5.):
        super(ClipboardWatcher, self).__init__()
        self._predicate = predicate
        self._callback = callback
        self._pause = 5
        self._stopping = False

    def run(self):
        recent_value = ""
        while not self._stopping:
            tmp_value = pyperclip.paste()
            if tmp_value != recent_value:
                recent_value = tmp_value
                if self._predicate(recent_value):
                    self._callback(recent_value)
            time.sleep(self._pause)

    def stop(self):
        self._stopping = True

def main():
    watcher = ClipboardWatcher(is_url_but_not_bitly, 
                               print_to_stdout,
                               5.) # up2u
    watcher.start()
    while True:
        try:
            time.sleep(10) # should be shorten
        except KeyboardInterrupt:
            watcher.stop()
            break


if __name__ == "__main__":
    main()