python マルチスレッドファイルをダウンロードコードメモ
注意内容：
1.ファイルサイズ： response headerから取得。例“Content-Length:911”はサイズ911バイト
2.タスク分割：request headerに“Range: bytes=300-400”を追加,rangeは「0,size-1」
3.ダウンロードファイルの集約：各スレッドでダウンロードしたファイルは一時ファイルとして保存。
すべてのスレッドが完了したら、一時ファイルを順番に最終一つのファイルに書き込む
サンプルコード
#!/usr/bin/python
# -*- coding: utf-8 -*-
# filename: paxel.py
# FROM: https://arkgame.com/full/
# Jay modified it a little and save for further potential usage.
"’It is a multi-thread downloading tool
It was developed following axel.
Author: volans
E-mail: volansw [at] gmail.com
"’
import sys
import os
import time
import urllib
from threading import Thread
# in case you want to use http_proxy
local_proxies = {'http’: 'http://XXX.XXX.XXX.XXX: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://XXX.com/apple_V3.1.1.dmg’
output = 'download.file’
paxel(url, output, blocks=4, proxies={})