爬虫代码没有改变每次爬取的数据不同？

Question

import pymongo
import requests
from lxml import etree
import time
import re

headers = {

    'User-Agent':'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/93.0.4577.82 Safari/537.36 Edg/93.0.961.52'
}

client = pymongo.MongoClient('localhost', 27017)  # 连接数据库
mydb = client['mydb']  # 创建库mydb
musictop = mydb['musictop250']  # 创建表
# 连接数据库

def get_url_music(url):
    """获取每个音乐的链接"""
    web_data = requests.get(url,headers=headers).content.decode()
    html = etree.HTML(web_data)
    selectors = html.xpath('//a[@class="nbg"]/@href')
    for selector in selectors:
        get_info(selector)

def get_info(url):
    """获取网页信息"""
    web_data = requests.get(url,headers=headers).content.decode()
    html = etree.HTML(web_data)
    songs = html.xpath('//*[@id="wrapper"]/h1/span/text()')[0]
    singers = re.findall(' 表演者:.*?<a href=".*?">(.*?)</a>',web_data,re.S)
    styles = re.findall('<span class="pl">流派:</span>&nbsp;(.*?)<br />',web_data,re.S)
    publish_time = re.findall(' <span class="pl">发行时间:</span>&nbsp;(.*?)<br />',web_data,re.S)
    rates = html.xpath('//*[@id="interest_sectl"]/div/div[2]/strong/text()'[0])
    if len(styles)==0:
        styles='未知'
    else:
        styles=styles[0].strip()
    if len(publish_time)==0:
            publish_time='未知'
    else:
        publish_time=publish_time[0].strip()
    if len(singers)==0:
        singers='未知'
    else:
        singers=singers[0].strip()
    print(songs,singers,publish_time,rates)
    data = {
        'song':songs,
        'singer':singers,
        'style':styles,
        'publish_time':publish_time,
        'rate':rates
        }
    musictop.insert_one(data)


if __name__ == '__main__':
    urls = ['https://music.douban.com/top250?start={}'.format(str(i)) for i in range(0, 250, 25)]
    for url in urls:
        get_url_music(url)
        time.sleep(2)

疑惑的问题

1. 每次运行的结果不一样
2. 有时候出现错误有时候没有错误
3. 有时候数据打印的时候都没打印完全就结束进程了

我都感觉是不是我电脑出问题了，希望大家能够帮我解决，谢谢

Answer 1

你应该发一发有什么错误，最佳250音乐，这本来就是可能变得，同时网络不好的时候，睡眠2秒是不够的，加上异常处理部分