app.py

import socket
import os
import sys
import argparse
import pyqrcode
import netifaces

downloads_dir = None

def render_qr_code(addr):
    """Generates a QR Code for the IP address and 
    displays it on the terminal.
    """
    url = pyqrcode.create(str(addr))
    url.svg("addr.svg", scale=8)
    url.eps("addr.eps", scale=2)
    print(url.terminal(quiet_zone=1))

def create_downloads_folder(path=None):
    """Creates the folder where to save the recieved files.
    If nothing is provided, `~/Downloads` is used by default.
    """
    if not path:
        path = os.path.join(os.environ['HOME'], 'Downloads')
    if not os.path.exists(path):
        os.makedirs(path)
    return path

def human(data):
    """Decodes byte string into human readable format
    """
    return data.decode("utf-8")

def run(port=None):
    """Opens up a socket connection on the port requested.
    If no value of port is supplied, port 9000 is used.
    """
    if not port:
        port = 9000
    host = get_ip()
    print('Scan the QR Code to connect :)')
    render_qr_code("{}:{}".format(host, port))
    try:
        connect_and_recv(host, port)
    except KeyboardInterrupt:
        print("Server stopped !")
    except Exception as e:
        print("Error: {}".format(e))

def get_ip():
    """Returns the IP address .
    """
    return str(netifaces.ifaddresses("en0")[netifaces.AF_INET][0]['addr'])

def connect_and_recv(host, port):
    """Starts a socket server and waits 
    for connection and recieve files.
    """
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    try:
        s.bind((host, port))
        s.listen(1)
    except Exception:
        s.close()
    while 1:
        # Accept a connection.
        conn, addr = s.accept()
        try:
            filename = str(conn.recv(1024).decode('utf-8')).rstrip('\n')
            print("Receiving : ", filename)
        except Exception as e:
            print("Something went wrong ! Could not recv filename !")

        try:
            receive_file(conn, filename)
        except Exception as e:
            print("Something went wrong ! Could not recv file !")
        # Close the connection.
        conn.close()

def receive_file(conn, filename):
    """Recieves  a file byte by byte over
    the connection.
    """
    f = open(os.path.join(downloads_dir, filename), 'wb')
    data = conn.recv(1024)
    while data:
        f.write(data)
        data = conn.recv(1024)
    f.close()
    print("File received successfully ! \n")


if __name__ == "__main__":
    art = """
           _        _____                  
     /\   (_)      |  __ \                 
    /  \   _ _ __  | |  | |_ __ ___  _ __  
   / /\ \ | | '__| | |  | | '__/ _ \| '_ \ 
  / ____ \| | |    | |__| | | | (_) | |_) |
 /_/    \_\_|_|    |_____/|_|  \___/| .__/ 
                                    | |    
                                    |_|    
    """
    print("\033[93m {}\033[00m" .format(art))
    parser = argparse.ArgumentParser()
    parser.add_argument('-p', type=int, help='The port number where to listen.')
    parser.add_argument('--dir', help='The directory where to save received files.')
    args = parser.parse_args()
    downloads_dir = create_downloads_folder(args.dir)
    print("Received files will be stored at {}".format(downloads_dir))
    run(args.p)