# 文件名：ThreadDownload.py
import threading
from urllib.request import *


class Download:
  def __init__(self, link, file_path, thread_num):
    # 下載路徑
    self.link = link
    # 保存位置
    self.file_path = file_path
    # 使用多少線程
    self.thread_num = thread_num
    # 初始化threads數(shù)組
    self.threads = []

  def download(self):
    req = Request(url=self.link, method='GET')
    req.add_header('Accept', '*/*')
    req.add_header('Charset', 'UTF-8')
    req.add_header('Connection', 'Keep-Alive')
    f = urlopen(req)
    # 獲取要下載的文件的大小
    self.file_size = int(dict(f.headers).get('Content-Length', 0))
    f.close()
    # 計(jì)算每個(gè)線程要下載的資源的大小
    current_part_size = self.file_size // self.thread_num + 1
    for i in range(self.thread_num):
      # 計(jì)算每個(gè)線程下載的開(kāi)始位置
      start_pos = i * current_part_size
      # 每個(gè)線程使用一個(gè)wb模式打開(kāi)的文件進(jìn)行下載
      t = open(self.file_path, 'wb')
      t.seek(start_pos, 0)
      # 創(chuàng)建下載線程
      td = ThreadDownload(self.link, start_pos, current_part_size, t)
      self.threads.append(td)
      td.start()

  # 獲下載的完成百分比
  def get_complete_rate(self):
    sum_size = 0
    for i in range(self.thread_num):
      sum_size += self.threads[i].length
    return sum_size / self.file_size

class ThreadDownload(threading.Thread):
  def __init__(self, link, start_pos, current_part_size, current_part):
    super().__init__() 
    # 下載路徑
    self.link = link
    # 當(dāng)前線程的下載位置
    self.start_pos = start_pos
    # 定義當(dāng)前線程負(fù)責(zé)下載的文件大小
    self.current_part_size = current_part_size
    # 當(dāng)前文件需要下載的文件快
    self.current_part = current_part
    # 定義該線程已經(jīng)下載的字節(jié)數(shù)
    self.length = 0
  
  def run(self):
    req = Request(url = self.link, method='GET')
    req.add_header('Accept', '*/*')
    req.add_header('Charset', 'UTF-8')
    req.add_header('Connection', 'Keep-Alive')

    f = urlopen(req)
    # 跳過(guò)self.start_pos個(gè)字節(jié)，表明該線程只負(fù)責(zé)下載自己負(fù)責(zé)的那部分內(nèi)容
    for i in range(self.start_pos):
      f.read(1)
    # 讀取網(wǎng)絡(luò)數(shù)據(jù)，并寫(xiě)入本地
    while self.length < self.current_part_size:
      data = f.read(1024)
      if data is None or len(data) <= 0:
        break
      self.current_part.write(data)
      # 累計(jì)該線程下載的總大小
      self.length += len(data)
    self.current_part.close()
    f.close()

#!/usr/bin/env python 
# -*- coding: utf-8 -*- 
# 文件名：thread_download-master.py

import sys
import time

from ThreadDownload import *


def show_process(dl):
  while dl.get_complete_rate() < 1:
    complete_rate = int(dl.get_complete_rate()*100) 
    print('\r' + '下載中···（已下載' + str(complete_rate) + '%）', end='', flush=True)
    time.sleep(0.01)


def main():
  try:  
    Link = input('[+]' + 'Link: ')
    file_path = input('[+]' + 'File Path: ')
    thread_number = input('[+]' + 'Thread Number: ')
    thread_number = int(thread_number)
    dl = Download(Link, file_path, thread_number)
    dl.download()
    print('\n開(kāi)始下載!')
    show_process(dl)
    print('\r' + '下載中···（已下載' + '100%)', end='', flush=True)
    print('\n下載完成!')
  except Exception:
      print('Parameter Setting Error')
      sys.exit(1)

if __name__=='__main__':
    main()