从yum源下载软件包

以下是从163源下载openstack-ocata版软件包的脚本：

from html.parser import HTMLParser
from urllib import request
import urllib
import os,sys
import socket
class myparser(HTMLParser):
    '''找到a标签并把属性的值放到列表里'''
    def __init__(self):
        HTMLParser.__init__(self)
        self.links = []
    def handle_starttag(self, tag, attrs):
        if tag == 'a':
            if len(attrs) == 0:
                pass
            else:
                for (variable,value) in attrs:
#                    print(value)
                    if variable == 'href':
                        self.links.append(value)
def callbackfunc(blocknum, blocksize, totalsize):
    '''回调函数,打印下载进度
    @blocknum: 已经下载的数据块
    @blocksize: 数据块的大小
    @totalsize: 远程文件的大小
    '''
    percent = int(100.0 * blocknum * blocksize / totalsize)
    if totalsize > 505528:
        pass
    else:
        percent = 100
    sys.stdout.write('\r')
    sys.stdout.write(file_name + percent * '>' + str(percent) + '%')
    sys.stdout.flush()
def create_dir(root_tree,catalog):
    '''根据url的目录结构在本地穿件文件夹'''
    os.chdir(root_tree)
    try:
        os.makedirs(catalog)
    except FileExistsError as e:
        pass

def download_file(url,down_path):
    '''下载文件保存到相应的目录，并把下载失败的放在一个字典里'''
    global file_name
    global error_download
    file_name =  url.split('/')[-1]
    error_download = {}
    socket.setdefaulttimeout(30)
    try:
        request.urlretrieve(url,down_path,callbackfunc)
    except socket.gaierror as e:
        error_download[url] = down_path
        print('socket.gaierror' , url)
    except urllib.error.URLError as e:
        error_download[url] = down_path
        print('urllib.error.URLError',url)
    sys.stdout.write('\n')

def get_url_tree(url_tree):
    '''获取一个字典，链接：目录，并把文件夹创建及把文件下载'''
    url_tree_dict = {}
    level = 0
    for url in url_tree:
        response = request.urlopen(url)
        page = response.read().decode('utf-8')
        hp = myparser()
        hp.feed(page)
        hp.close()
        try:
            hp.links.remove("../")
        except ValueError as e:
            pass
        for file in hp.links:
            if '/' in file:
                create_dir(url_tree[url], file)
                url_tree_dict[url+file] = url_tree[url]+file
            else:
                download_file(url+file,url_tree[url]+file)
            if file.find('/') > 0:
                level += 1
    return url_tree_dict , level
url_tree = {"http://mirrors.163.com/centos/7/cloud/x86_64/openstack-ocata/":'/centos/7/cloud/x86_64/openstack-ocata/'}
try:
    os.makedirs('/centos/7/cloud/x86_64/openstack-ocata/')
except FileExistsError as e:
    pass

while True:
    url_tree,level = get_url_tree(url_tree)
    if level == 0:
        break
    print(url_tree,level)
for key in error_download:
    download_file(key,error_download[key])