python爬虫 登陆豆瓣 爬豆瓣电影短评

       这个爬虫的目的是爬取豆瓣电影短评和评分（从1星到5星），这些东西可以做情感分类。由于不登录的情况下只能看电影短评的前几页，所以要实现登陆豆瓣。
       登陆豆瓣的部分是在网上看的别人的代码，忘了从哪看的了。
# -*- coding: utf-8 -*-
from bs4 import BeautifulSoup
import re
from time import sleep
import random
import urllib
import requests

url = "https://douban.com/accounts/login"
formData = {
    "redir": "https://www.douban.com",
    "form_email": "**************",
    "form_password": "**************",
    "login": u'登录',
    'source': 'None',
}

headers = {"User-Agent": "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/50.0.2661.87 Safari/537.36",
           "Referer": "https://douban.com/accounts/login",
           "Host": "accounts.douban.com",
           "Connection": "Keep-Alive",
           "Content-Type": "application/x-www-form-urlencoded"
           }
s = requests.session()
# r_ = s.post(url, data=formData, headers=headers)
# a = r_.text
# soup_ = BeautifulSoup(a, "html.parser")
# captchaAddr = soup_.find('img', id='captcha_image')['src']
# reCaptchaID = r'<input type="hidden" name="captcha-id" value="(.*?)"/'
# captchaID = re.findall(reCaptchaID, a)
# urllib.urlretrieve(captchaAddr, "captcha.jpg")
#
# captcha = raw_input('please input the captcha:')
# formData['captcha-solution'] = captcha
# formData['captcha-id'] = captchaID
r_ = s.post(url, data=formData, headers=headers)
page_ = r_.text
# print page_
# co = r_.cookies
"""---------------------------------------------------------------------------------"""
number = 0

def process_h3(soup, fp):
    global number
    h3s = soup.findAll("h3")
    for i in h3s:
        aa = i.span.next_siblings
        bb = aa.next().next()
        number += 1
        if number % 100 == 0:
            print number
        if len(bb) == 4:
            fp.write(bb[2].attrs["class"][0][-2:-1])
            fp.write(" ")
            cc = i.next_siblings
            cc.next()
            dd = cc.next().get_text().strip()
            ee = dd.replace('\n', " ")
            fp.write(ee.encode("utf8"))
            # print ee.encode("utf8")
            fp.write('\n')

def find_next(soup):
    line = soup.findAll("a", {"class", "next"})
    if len(line) == 0:
        return None
    else:
        href = line[0].attrs["href"]
        return target + href

"""---------------------------------------------------------------------------------"""
target = "https://movie.douban.com/subject/25944714/comments"
"""------------------------------------------------------------------------   params"""
movie = s.get(target)  # , cookies=co)
page_movie = movie.text
# print page_movie
# print movie.status_code
soupMovie = BeautifulSoup(page_movie)
numb_ = soupMovie.findAll("ul", {"class": "fleft"})
print "total:", re.findall('(\d+)', numb_[0].text)[0]
movieName = soupMovie.find("title").get_text()[:-3]
print movieName
with open(movieName + ".txt", 'w') as fp:
    process_h3(soupMovie, fp)
    while True:
        inter = random.gauss(9, 2)
        time = inter if inter > 2.1 else 2.1
        sleep(time)
        next_ = find_next(soupMovie)
        if next_ is None:
            break
        try:
            soupMovie = BeautifulSoup(s.get(next_, timeout=10).text)
            process_h3(soupMovie, fp)
        except:
            sleep(100)
            try:
                soupMovie = BeautifulSoup(s.get(next_, timeout=10).text)
                process_h3(soupMovie, fp)
            except:
                break



          登陆豆瓣的时候刚开始不用验证码，登陆次数多了再登就需要验证码了，当需要验证码时，把以下代码的注释去掉，程序会将验证码图片下载下来，再提示你输入验证码，照图片上的验证码输入就可以了。

# r_ = s.post(url, data=formData, headers=headers)
# a = r_.text
# soup_ = BeautifulSoup(a, "html.parser")
# captchaAddr = soup_.find('img', id='captcha_image')['src']
# reCaptchaID = r'<input type="hidden" name="captcha-id" value="(.*?)"/'
# captchaID = re.findall(reCaptchaID, a)
# urllib.urlretrieve(captchaAddr, "captcha.jpg")

# captcha = raw_input('please input the captcha:')
# formData['captcha-solution'] = captcha
# formData['captcha-id'] = captchaID

            这个爬虫每次运行会爬取一部电影的所有影评，需要指定该电影短评的首页网址，如下面的代码所示。

"""---------------------------------------------------------------------------------"""
target = "https://movie.douban.com/subject/25944714/comments"
"""------------------------------------------------------------------------   params"""

            爬虫开始时会输出短评总数以及电影名称，每经过100条输出一次提示。结果保存在以电影名命名的txt文件中。（注：该爬虫忽略了只有评价内容而没有评分的短评）。
       从指定的第一页开始，程序每爬一页都会去找下一页的链接，接着去爬。其实不一定要从第一页开始，从任意页开始都行。每爬完一页，将等待一段时间，等待的时间长短服从均值为9，标准差为2的高斯分布，这是为了使爬虫行为更加没有规律。

       很多电影短评到最后几页无法访问，所以程序在连续两次无法访问之后就会停止。
       
       爬到的数据如下图所示：



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