1.[代码][Python]代码

Python语言: Python实现多线程下载

#!/usr/bin/python

# -*- coding: utf-8 -*-

# filename: paxel.py

'''It is a multi-thread downloading tool

It was developed follow axel.

Author: volans

E-mail: volansw [at] gmail.com

'''

import sys

import os

import time

import urllib

from threading import Thread

local_proxies = {'http': 'http://131.139.58.200:8080'}

class AxelPython(Thread, urllib.FancyURLopener):

'''Multi-thread downloading class.

run() is a vitural method of Thread.

'''

def __init__(self, threadname, url, filename, ranges=0, proxies={}):

Thread.__init__(self, name=threadname)

urllib.FancyURLopener.__init__(self, proxies)

self.name = threadname

self.url = url

self.filename = filename

self.ranges = ranges

self.downloaded = 0

def run(self):

'''vertual function in Thread'''

try:

self.downloaded = os.path.getsize( self.filename )

except OSError:

#print 'never downloaded'

self.downloaded = 0

# rebuild start poind

self.startpoint = self.ranges[0] + self.downloaded

# This part is completed

if self.startpoint >= self.ranges[1]:

print 'Part %s has been downloaded over.' % self.filename

return

self.oneTimeSize = 16384 #16kByte/time

print 'task %s will download from %d to %d' % (self.name, self.startpoint, self.ranges[1])

self.addheader("Range", "bytes=%d-%d" % (self.startpoint, self.ranges[1]))

self.urlhandle = self.open( self.url )

data = self.urlhandle.read( self.oneTimeSize )

while data:

filehandle = open( self.filename, 'ab+' )

filehandle.write( data )

filehandle.close()

self.downloaded += len( data )

#print "%s" % (self.name)

#progress = u'\r...'

data = self.urlhandle.read( self.oneTimeSize )

def GetUrlFileSize(url, proxies={}):

urlHandler = urllib.urlopen( url, proxies=proxies )

headers = urlHandler.info().headers

length = 0

for header in headers:

if header.find('Length') != -1:

length = header.split(':')[-1].strip()

length = int(length)

return length

def SpliteBlocks(totalsize, blocknumber):

blocksize = totalsize/blocknumber

ranges = []

for i in range(0, blocknumber-1):

ranges.append((i*blocksize, i*blocksize +blocksize - 1))

ranges.append(( blocksize*(blocknumber-1), totalsize -1 ))

return ranges

def islive(tasks):

for task in tasks:

if task.isAlive():

return True

return False

def paxel(url, output, blocks=6, proxies=local_proxies):

''' paxel

'''

size = GetUrlFileSize( url, proxies )

ranges = SpliteBlocks( size, blocks )

threadname = [ "thread_%d" % i for i in range(0, blocks) ]

filename = [ "tmpfile_%d" % i for i in range(0, blocks) ]

tasks = []

for i in range(0,blocks):

task = AxelPython( threadname[i], url, filename[i], ranges[i] )

task.setDaemon( True )

task.start()

tasks.append( task )

time.sleep( 2 )

while islive(tasks):

downloaded = sum( [task.downloaded for task in tasks] )

process = downloaded/float(size)*100

show = u'\rFilesize:%d Downloaded:%d Completed:%.2f%%' % (size, downloaded, process)

sys.stdout.write(show)

sys.stdout.flush()

time.sleep( 0.5 )

filehandle = open( output, 'wb+' )

for i in filename:

f = open( i, 'rb' )

filehandle.write( f.read() )

f.close()

try:

os.remove(i)

pass

except:

pass

filehandle.close()

if __name__ == '__main__':

url = "http://www.pygtk.org/dist/pygtk2-tut.pdf"

output = 'pygtk2.pdf'

paxel( url, output, blocks=4, proxies={} )