爬取https://movie.douban.com/subject/1305690/所有短评的代码

以下是使用Python和BeautifulSoup库爬取豆瓣电影《肖申克的救赎》(https://movie.douban.com/subject/1305690/)所有短评的代码：

import requests
from bs4 import BeautifulSoup

url = 'https://movie.douban.com/subject/1305690/comments?start=0&limit=20&sort=new_score&status=P'

headers = {
    'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.3'}

comments = []

while True:
    response = requests.get(url, headers=headers)
    soup = BeautifulSoup(response.text, 'html.parser')
    comment_div_list = soup.find_all('div', class_='comment')
    for comment_div in comment_div_list:
        comment = comment_div.find('span', class_='short').text.strip()
        comments.append(comment)
    next_page = soup.find('a', class_='next')
    if next_page:
        url = 'https://movie.douban.com' + next_page['href']
    else:
        break

print(comments)

注：以上代码可能会触发豆瓣的反爬虫机制，建议使用代理或者加入适当的延时等策略来规避反爬虫机制。另外，爬虫行为需要遵守相关法律法规和网站的Robots协议。