python 3.4

#!/usr/bin/env python
# coding=utf-8
import urllib
import urllib.request
import re
import time

from threading import *
from bs4 import BeautifulSoup

# 控制共享资源的访问数量
screenLock = Semaphore(value = 1)
# headers
headers = {
    'User-Agent':'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/51.0.2704.63 Safari/537.36'
}
main_url = 'http://www.symmz.com'
num = 1
# set 无序不重复元素集
pages = set()
pages.add(main_url)

# 防止jpg 重复
srces = set()

def downloadimg(url,depth):
    if depth != 0:
        print (depth)
        print (url) 
        req = urllib.request.Request(url, headers=headers)
        try:
            res_html = urllib.request.urlopen(req).read().decode('utf-8')
        except urllib.HTTPError:
            print ('异常～')
        # 创建 BeautifulSoup对象
        soup = BeautifulSoup(res_html,'html.parser')
        imgurllist = soup.find_all('img',{'src':re.compile(r'http://.+.jpg')})
        urllist = soup.find_all('a',{'href':re.compile(r'/.+?/.+?.html')})
        local_pash = './symmzImg01/'
        # 全局变量
        global num
        for item in imgurllist:
            print (" src:" + item['src'])
            url = item['src']
            if url not in srces:
                path = local_pash + str(num) + '.jpg'
                # 直接将远程文件下载到本地
                urllib.request.urlretrieve(url,path)
                # 将图片url 存到set中
                srces.add(url)
                num += 1
                # 锁
                screenLock.acquire()
                print (str(num) + '.jpg 已下载\n')
                screenLock.release()
            else:
                print('url 重复～'+url)
        # 深搜
        for url in urllist:
            if url not in pages:
                global main_url
                pattern = re.compile(r'http://')
                newurl = main_url + url['href']
                # 判断url 中是否有两个 http
                if(len(re.findall(pattern,newurl)) > 1):
                    newurl = url['href']
                print('newurl:'+newurl)
                downloadimg(newurl, depth-1)
                # 不要加入 重复url
                pages.add(url)
                time.sleep(1)
            else:
                return 

def start():
    downloadimg(main_url,3)
if __name__ == '__main__':
    start()