python爬蟲實現(xiàn)自動登錄與驗證碼識別的方法

#coding:utf-8
import sys
import time
import urllib
import shutil
import pytesser
import requests

from lxml import etree

config = {'gid': 1}

def parse(s, html, idx):
 result = {}

 tree = etree.HTML(html)
 try:
 result['lt'] = tree.xpath('//input[@name="lt"]/@value')[0]
 result['execution'] = tree.xpath('//input[@name="execution"]/@value')[0]
 result['path'] = tree.xpath('//form[@id="fm1"]/@action')[0]
 except IndexError, e:
 return None

 valimg = None
 valimgs = tree.xpath('//img[@id="yanzheng"]/@src')
 if len(valimgs) > 0:
 valimg = valimgs[0]

 validateCode = None
 if valimg:
 fname = 'img/' + str(idx) + '_' + str(config['gid']) + '.jpg'
 config['gid'] = config['gid'] + 1
 ri = s.get("https://passport.csdn.net" + valimg)
 with open(fname, 'wb') as f:
  for chk in ri:
  f.write(chk)
  f.close()
 validateCode = pytesser.image_file_to_string(fname)
 validateCode = validateCode.strip()
 validateCode = validateCode.replace(' ', '')
 validateCode = validateCode.replace('\n', '')
 result['validateCode'] = validateCode

 return result

def login(usr, pwd, idx):
 s = requests.Session()

 r = s.get('https://passport.csdn.net/account/login',
 headers={'User-Agent': 'Mozilla/5.0 (Windows NT 6.1; WOW64; rv:41.0) Gecko/20100101 Firefox/41.0', 'Host': 'passport.csdn.net', })

 while True:
 res = parse(s, r.text, idx)
 if res == None:
  return False
 url = 'https://passport.csdn.net' + res['path']
 form = {'username': usr, 'password':pwd, '_eventId':'submit', 'execution':res['execution'], 'lt':res['lt'],}
 if res.has_key('validateCode'):
  form['validateCode'] = res['validateCode']
 s.headers.update({
  'User-Agent': 'Mozilla/5.0 (Windows NT 6.1; WOW64; rv:41.0) Gecko/20100101 Firefox/41.0',
  'Accept-Language': 'zh-CN,zh;q=0.8,en-US;q=0.6,en;q=0.4',
  'Content-Type': 'application/x-www-form-urlencoded',
  'Host': 'passport.csdn.net',
  'Origin': 'https://passport.csdn.net',
  'Referer': 'https://passport.csdn.net/account/login',
  'Upgrade-Insecure-Requests': 1,
  })
 r = s.post(url, data=form)

 tree = etree.HTML(r.text)
 err_strs = tree.xpath('//span[@id="error-message"]/text()')
 if len(err_strs) == 0:
  return True
 err_str = err_strs[0]
 print err_str
 err = err_str.encode('utf8')

 validate_code_err = '驗證碼錯誤'
 usr_pass_err = '帳戶名或登錄密碼不正確，請重新輸入'
 try_later_err = '登錄失敗連續(xù)超過5次，請10分鐘后再試'

 if err[:5] == validate_code_err[:5]:
  pass
 elif err[:5] == usr_pass_err[:5]:
  return False
 elif err[:5] == try_later_err[:5]:
  return False
 else:
  return True

if __name__ == '__main__':
 main(sys.argv[1], sys.argv[2], 0)