communication.py

#!/usr/bin/python

import socket
import subprocess
import constants as c
import time


def send_broadcast_message(port, message):
    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    sock.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
    try:
        sock.sendto(message, ('192.168.178.255', port))
        string = "message: \'" + message + "\' sent"
        return string
    except socket.error:
        return "Error while sending!"
    finally:
        sock.close()

  
def send_x_broadcast_messages(port, message, x, time_between):
    for iteration in range(x):
        send_broadcast_message(port, message)
        time.sleep(time_between)   


def send_udp_unicast_message(address, port, message):
    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    try:
        sock.sendto(message, (address, port))
        return "Sent: " + str(message) + " to " + str(address) + " on port " + str(port)
    except socket.error as e:
        return "Error while sending : ", e
    finally:
        sock.close()


def init_receiver(address, port):
    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    sock.bind((address, port))
    return sock


def init_nonblocking_receiver(address, port):
    sock = init_receiver(address, port)
    sock.setblocking(0)
    return sock


def init_blocking_receiver(address, port, timeout):
    sock = init_receiver(address, port)
    sock.settimeout(timeout)
    return sock


def close_socket(sock):
    sock.close()


def receive_message(sock):
    data = ""
    addr = ""
    try:
        data, addr = sock.recvfrom(1024)
        # print "received message: " +  data + " at: %f" %time.time()
    except socket.error as e:
        # print e
        pass
    finally:
        return data, addr


def receive_message_list(sock):
    message_list = []
    cur_data, cur_addr = receive_message(sock)
    while cur_data != '':
        message_list.append((cur_data, get_id_from_ip(cur_addr)))
        cur_data, cur_addr = receive_message(sock)
    return message_list


def get_ip():
    ip = subprocess.check_output(['hostname', '-I'])
    return ip[:-2]


def get_id_from_ip(ip_addr):
    return int(ip_addr.split('.')[3])


def get_id():
    ip = get_ip()
    return get_id_from_ip(ip)
 

def string_to_command(data):
    strings = data.split(' ')
    command = strings[0]
    if len(strings) > 1:
        value = strings[1]
    else:
        value = ''
    if (command == c.COMMAND_SPEED or command == c.COMMAND_DIST) and value.isdigit():
        value = int(value)
    return command, value