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python 实现的 ping 功能(web.py版)

发布时间:2012-04-14 22:20:30, 关注:+8154, 赞美:+6, 不爽:+425

原始出处: 591RMB

最近公司的网络不太给力,导致电话偶尔会出现咔咔的问题,我们的第一反应,查看服务器,得到的答案永远是ping值太大,通过回复同事都是网络不好,要稍等一会。

由此引申出一个问题:如果同事能够自己判断就好了,避免经常过来“搔扰”我们。

答案是:自动化的显示在后台,让同事查看即可。

根据以往对python的简单了解,Google一下ping的python实现,结合web.py,很简单的实现了功能,源码如下:

#coding:utf-8
"""
web.py + ping
www.591rmb.info
ex:
# nohup web_ping.py 9999 &
# curl http://192.168.1.36:9999/192.168.1.86
ping Code,Copy from the following website:
http://www.g-loaded.eu/2009/10/30/python-ping/
"""
import socket, select, time, web, urllib
import os, sys, socket, struct, select, time

urls = (
    '/(.*)', 'Ping'
)

app = web.application(urls, globals())

class Ping:
    def GET(self, ip):
        return verbose_ping(ip, 2, 1)

# From /usr/include/linux/icmp.h; your milage may vary.
ICMP_ECHO_REQUEST = 8 # Seems to be the same on Solaris.


def checksum(source_string):
    """
    I'm not too confident that this is right but testing seems
    to suggest that it gives the same answers as in_cksum in ping.c
    """
    sum = 0
    countTo = (len(source_string)/2)*2
    count = 0
    while count<countTo:
        thisVal = ord(source_string[count + 1])*256 + ord(source_string[count])
        sum = sum + thisVal
        sum = sum & 0xffffffff # Necessary?
        count = count + 2

    if countTo<len(source_string):
        sum = sum + ord(source_string[len(source_string) - 1])
        sum = sum & 0xffffffff # Necessary?

    sum = (sum >> 16)  +  (sum & 0xffff)
    sum = sum + (sum >> 16)
    answer = ~sum
    answer = answer & 0xffff

    # Swap bytes. Bugger me if I know why.
    answer = answer >> 8 | (answer << 8 & 0xff00)

    return answer


def receive_one_ping(my_socket, ID, timeout):
    """
    receive the ping from the socket.
    """
    timeLeft = timeout
    while True:
        startedSelect = time.time()
        whatReady = select.select([my_socket], [], [], timeLeft)
        howLongInSelect = (time.time() - startedSelect)
        if whatReady[0] == []: # Timeout
            return

        timeReceived = time.time()
        recPacket, addr = my_socket.recvfrom(1024)
        icmpHeader = recPacket[20:28]
        type, code, checksum, packetID, sequence = struct.unpack(
            "bbHHh", icmpHeader
        )
        if packetID == ID:
            bytesInDouble = struct.calcsize("d")
            timeSent = struct.unpack("d", recPacket[28:28 + bytesInDouble])[0]
            return timeReceived - timeSent

        timeLeft = timeLeft - howLongInSelect
        if timeLeft <= 0:
            return


def send_one_ping(my_socket, dest_addr, ID):
    """
    Send one ping to the given >dest_addr<.
    """
    dest_addr  =  socket.gethostbyname(dest_addr)

    # Header is type (8), code (8), checksum (16), id (16), sequence (16)
    my_checksum = 0

    # Make a dummy heder with a 0 checksum.
    header = struct.pack("bbHHh", ICMP_ECHO_REQUEST, 0, my_checksum, ID, 1)
    bytesInDouble = struct.calcsize("d")
    data = (192 - bytesInDouble) * "Q"
    data = struct.pack("d", time.time()) + data

    # Calculate the checksum on the data and the dummy header.
    my_checksum = checksum(header + data)

    # Now that we have the right checksum, we put that in. It's just easier
    # to make up a new header than to stuff it into the dummy.
    header = struct.pack(
        "bbHHh", ICMP_ECHO_REQUEST, 0, socket.htons(my_checksum), ID, 1
    )
    packet = header + data
    my_socket.sendto(packet, (dest_addr, 1)) # Don't know about the 1


def do_one(dest_addr, timeout):
    """
    Returns either the delay (in seconds) or none on timeout.
    """
    icmp = socket.getprotobyname("icmp")
    try:
        my_socket = socket.socket(socket.AF_INET, socket.SOCK_RAW, icmp)
    except socket.error, (errno, msg):
        if errno == 1:
            # Operation not permitted
            msg = msg + (
                " - Note that ICMP messages can only be sent from processes"
                " running as root."
            )
            raise socket.error(msg)
        raise # raise the original error

    my_ID = os.getpid() & 0xFFFF

    send_one_ping(my_socket, dest_addr, my_ID)
    delay = receive_one_ping(my_socket, my_ID, timeout)

    my_socket.close()
    return delay


def verbose_ping(dest_addr, timeout = 2, count = 4):
    """
    Send >count< ping to >dest_addr< with the given >timeout< and display
    the result.
    """
    result = ''
    for i in xrange(count):
        result = "ping " + dest_addr
        try:
            delay  =  do_one(dest_addr, timeout)
        except socket.gaierror, e:
            result += " failed. (socket error: '%s')" % e[1]
            break

        if delay  ==  None:
            result += " failed. (timeout within %ssec.)" % timeout
        else:
            delay  =  delay * 1000
            result += " => %dms" % delay
    return result



if __name__ == "__main__":
    def void(s): pass
    app.run()

 

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