看到网上也有开源的代码，这不，我拿来进行了二次重写，呵呵，上代码：
代码如下:
#encoding: utf-8
import socket
from hashlib import sha1
from random import randint
from struct import unpack, pack
from socket import inet_aton, inet_ntoa
from bisect import bisect_left
from threading import Timer
from time import sleep
import MySQLdb
from datetime import *
import time
from bencode import bencode, bdecode
BOOTSTRAP_NODES = [
("router.bittorrent.com", 6881),
("dht.transmissionbt.com", 6881),
("router.utorrent.com", 6881)
]
TID_LENGTH = 4
KRPC_TIMEOUT = 10
REBORN_TIME = 5 * 60
K = 8
def entropy(bytes):
s = ""
for i in range(bytes):
s += chr(randint(0, 255))
return s
def random_id():
hash = sha1()
hash.update( entropy(20) )
return hash.digest()
def decode_nodes(nodes):
n = []
length = len(nodes)
if (length % 26) != 0:
return n
for i in range(0, length, 26):
nid = nodes[i:i+20]
ip = inet_ntoa(nodes[i+20:i+24])
port = unpack("!H", nodes[i+24:i+26])[0]
n.append( (nid, ip, port) )
return n
def encode_nodes(nodes):
strings = []
for node in nodes:
s = "%s%s%s" % (node.nid, inet_aton(node.ip), pack("!H", node.port))
strings.append(s)
return "".join(strings)
def intify(hstr):
return long(hstr.encode('hex'), 16)
def timer(t, f):
Timer(t, f).start()
class BucketFull(Exception):
pass
class KRPC(object):
def __init__(self):
self.types = {
"r": self.response_received,
"q": self.query_received
}
self.actions = {
"ping": self.ping_received,
"find_node": self.find_node_received,
"get_peers": self.get_peers_received,
"announce_peer": self.announce_peer_received,
}
self.socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
self.socket.bind(("0.0.0.0", self.port))
def response_received(self, msg, address):
self.find_node_handler(msg)
def query_received(self, msg, address):
try:
self.actions[msg["q"]](msg, address)
except KeyError:
pass
def send_krpc(self, msg, address):
try:
self.socket.sendto(bencode(msg), address)
except:
pass
class Client(KRPC):
def __init__(self, table):
self.table = table
timer(KRPC_TIMEOUT, self.timeout)
timer(REBORN_TIME, self.reborn)
KRPC.__init__(self)
def find_node(self, address, nid=None):
nid = self.get_neighbor(nid) if nid else self.table.nid
tid = entropy(TID_LENGTH)
msg = {
"t": tid,
"y": "q",
"q": "find_node",
"a": {"id": nid, "target": random_id()}
}
self.send_krpc(msg, address)
def find_node_handler(self, msg):
try:
nodes = decode_nodes(msg["r"]["nodes"])
for node in nodes:
(nid, ip, port) = node
if len(nid) != 20: continue
if nid == self.table.nid: continue
self.find_node( (ip, port), nid )
except KeyError:
pass
def joinDHT(self):
for address in BOOTSTRAP_NODES:
self.find_node(address)
def timeout(self):
if len( self.table.buckets ) < 2:
self.joinDHT()
timer(KRPC_TIMEOUT, self.timeout)
def reborn(self):
self.table.nid = random_id()
self.table.buckets = [ KBucket(0, 2**160) ]
timer(REBORN_TIME, self.reborn)
def start(self):
self.joinDHT()
while True:
try:
(data, address) = self.socket.recvfrom(65536)
msg = bdecode(data)
self.types[msg["y"]](msg, address)
except Exception:
pass
def get_neighbor(self, target):
return target[:10]+random_id()[10:]
class Server(Client):
def __init__(self, master, table, port):
self.table = table
self.master = master
self.port = port
Client.__init__(self, table)
def ping_received(self, msg, address):
try:
nid = msg["a"]["id"]
msg = {
"t": msg["t"],
"y": "r",
"r": {"id": self.get_neighbor(nid)}
}
self.send_krpc(msg, address)
self.find_node(address, nid)
except KeyError:
pass
def find_node_received(self, msg, address):
try:
target = msg["a"]["target"]
neighbors = self.table.get_neighbors(target)
nid = msg["a"]["id"]
msg = {
"t": msg["t"],
"y": "r",
"r": {
"id": self.get_neighbor(target),
"nodes": encode_nodes(neighbors)
}
}
self.table.append(KNode(nid, *address))
self.send_krpc(msg, address)
self.find_node(address, nid)
except KeyError:
pass
def get_peers_received(self, msg, address):
try:
infohash = msg["a"]["info_hash"]
neighbors = self.table.get_neighbors(infohash)
nid = msg["a"]["id"]
msg = {
"t": msg["t"],
"y": "r",
"r": {
"id": self.get_neighbor(infohash),
"nodes": encode_nodes(neighbors)
}
}
self.table.append(KNode(nid, *address))
self.send_krpc(msg, address)
self.master.log(infohash)
self.find_node(address, nid)
except KeyError:
pass
def announce_peer_received(self, msg, address):
try:
infohash = msg["a"]["info_hash"]
nid = msg["a"]["id"]
msg = {
"t": msg["t"],
"y": "r",
"r": {"id": self.get_neighbor(infohash)}
}
self.table.append(KNode(nid, *address))
self.send_krpc(msg, address)
self.master.log(infohash)
self.find_node(address, nid)
except KeyError:
pass
class KTable(object):
def __init__(self, nid):
self.nid = nid
self.buckets = [ KBucket(0, 2**160) ]
def append(self, node):
index = self.bucket_index(node.nid)
try:
bucket = self.buckets[index]
bucket.append(node)
except IndexError:
return
except BucketFull:
if not bucket.in_range(self.nid): return
self.split_bucket(index)
self.append(node)
def get_neighbors(self, target):
nodes = []
if len(self.buckets) == 0: return nodes
if len(target) != 20 : return nodes
index = self.bucket_index(target)
try:
nodes = self.buckets[index].nodes
min = index - 1
max = index + 1
while len(nodes) < K and ((min >= 0) or (max < len(self.buckets))):
if min >= 0:
nodes.extend(self.buckets[min].nodes)
if max < len(self.buckets):
nodes.extend(self.buckets[max].nodes)
min -= 1
max += 1
num = intify(target)
nodes.sort(lambda a, b, num=num: cmp(num^intify(a.nid), num^intify(b.nid)))
return nodes[:K]
except IndexError:
return nodes
def bucket_index(self, target):
return bisect_left(self.buckets, intify(target))
def split_bucket(self, index):
old = self.buckets[index]
point = old.max - (old.max - old.min)/2
new = KBucket(point, old.max)
old.max = point
self.buckets.insert(index + 1, new)
for node in old.nodes[:]:
if new.in_range(node.nid):
new.append(node)
old.remove(node)
def __iter__(self):
for bucket in self.buckets:
yield bucket
class KBucket(object):
__slots__ = ("min", "max", "nodes")
def __init__(self, min, max):
self.min = min
self.max = max
self.nodes = []
def append(self, node):
if node in self:
self.remove(node)
self.nodes.append(node)
else:
if len(self) < K:
self.nodes.append(node)
else:
raise BucketFull
def remove(self, node):
self.nodes.remove(node)
def in_range(self, target):
return self.min