使用Python3编写抓取网页和只抓网页图片的脚本

最基本的抓取网页内容的代码实现：

#!/usr/bin/env python 

from urllib import urlretrieve 

def firstNonBlank(lines):
  for eachLine in lines:
    if not eachLine.strip():
      continue
    else:
      return eachLine 

def firstLast(webpage):
  f = open(webpage)
  lines = f.readlines()
  f.close()
  print firstNonBlank(lines),
  lines.reverse()
  print firstNonBlank(lines), 

def download(url='http://www',process=firstLast):
  try:
    retval = urlretrieve(url)[0]
  except IOError:
    retval = None
  if retval:
    process(retval) 

if __name__ == '__main__':
  download()

利用urllib模块，来实现一个网页中针对图片的抓取功能：

import urllib.request
import socket
import re
import sys
import os
targetDir = r"C:\Users\elqstux\Desktop\pic"
def destFile(path):
  if not os.path.isdir(targetDir):
    os.mkdir(targetDir)
  pos = path.rindex('/')
  t = os.path.join(targetDir, path[pos+1:])
  return t 

if __name__ == "__main__":
  hostname = "http://www.douban.com"
  req = urllib.request.Request(hostname)
  webpage = urllib.request.urlopen(req)
  contentBytes = webpage.read()
  for link, t in set(re.findall(r'(http:[^\s]*?(jpg|png|gif))', str(contentBytes))):
    print(link)
    urllib.request.urlretrieve(link, destFile(link))

import urllib.request
import socket
import re
import sys
import os
targetDir = r"H:\pic"
def destFile(path):
  if not os.path.isdir(targetDir):
    os.mkdir(targetDir)
  pos = path.rindex('/')
  t = os.path.join(targetDir, path[pos+1:]) #会以/作为分隔
  return t 

if __name__ == "__main__":
  hostname = "http://www.douban.com/"
  req = urllib.request.Request(hostname)
  webpage = urllib.request.urlopen(req)
  contentBytes = webpage.read()
  match = re.findall(r'(http:[^\s]*?(jpg|png|gif))', str(contentBytes) )#r'(http:[^\s]*?(jpg|png|gif))'中包含两层圆括号，故有两个分组，
                             #上面会返回列表，括号中匹配的内容才会出现在列表中
  for picname, picType in match:
    print(picname)
    print(picType) 

'''''
输出：
http://img3.douban.com/pics/blank.gif
gif
http://img3.douban.com/icon/g111328-1.jpg
jpg
http://img3.douban.com/pics/blank.gif
gif
http://img3.douban.com/icon/g197523-19.jpg
jpg
http://img3.douban.com/pics/blank.gif
gif
...
'''