python爬虫学习--爬好看网视频

爬虫前的准备

python爬虫的三元素

数据抓取、数据解析、数据存储

使用到的python第三方库

json（不需要安装）、request（需要安装）

request安装的方法

爬虫步骤

网页分析

爬虫的第一步就是进行网页分析，找到找到要爬取的值

通过访问该链接，得到json格式如下：

json格式

外面用{}包起来，里面是键值对的形式
{"key":"value"}
存在嵌套现象
{"key":"{"key":"value"}"}

重点是在嵌套中爬取搭到value值

代码示例

爬好看视频网的代码示例：

import json
import requests
# 第一步：数据的抓取
# 定义一个变量，用于存取爬取到的数据
base_url ='https://haokan.baidu.com/web/video/feed?tab=yingshi_new&act=pcFeed&pd=pc&num=5&shuaxin_id=1623571294796'
# 反反爬
headers = {
     
    # User-Agent
    'user-agent':'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/89.0.4389.128 Safari/537.36',
    # Referer 用于判断你是从哪个页面跳过来的
    'referer':'https://haokan.baidu.com/?fr=pc_pz',
    # Cookie 用于判断是否你登录（如果没有登录，是没有cookie的）
    'cookie':'BIDUPSID=05FEFAC34AEB974EB63623DBB54F3765; PSTM=1590673047; __yjs_duid=1_223b526dd2e6b4ea4aa28b6a28e3398a1618362899184; BAIDUID=05FEFAC34AEB974EF3880088E7AC8536:SL=0:NR=10:FG=1; BAIDUID_BFESS=05FEFAC34AEB974EF3880088E7AC8536:SL=0:NR=10:FG=1; BDRCVFR[w-kNo__JL0t]=1jmUUpB1KcCmh7GmLNEmi4WUvY; delPer=0; PSINO=1; H_PS_PSSID=34099_31253_33848_33607_34094_26350; BA_HECTOR=a1aha4052hakah804b1gcbeil0q; BDORZ=B490B5EBF6F3CD402E515D22BCDA1598; BDRCVFR[fb3VbsUruOn]=rJZwba6_rOCfAF9pywd; BCLID=11157415508952475120; BDSFRCVID=YiuOJexroG38bzJevE5BMBPcTOqMFyTTDYLEJs2qYShnrsPVJeC6EG0PtoWQkz--EHtdogKKBmOTHgKF_2uxOjjg8UtVJeC6EG0Ptf8g0M5; H_BDCLCKID_SF=tR3aQ5rtKRTffjrnhPF3KhDfXP6-hnjy3bAO3tFa54QpHRcELl3j3M4LXtj8Lp3RymJJ2-39LPO2hpRjyxv4y4Ldj4oxJpOJaavIB-FEHl51fbbvbURvL4ug3-7MBM5dtjTO2bc_5KnlfMQ_bf--QfbQ0hOhqP-jBRIEoCvt-5rDHJTg5DTjhPrM3RjdWMT-MTryKK8yKtFhetQHjf5YLl8S3-nDWx58QNnRhlR2B-3iV-OxDUvnyxAZyxomtfQxtNRJWM3l2-FVKq5S5-OobUPULxc9LUvMW2cdot5yBbc8eIna5hjkbfJBQttjQn3hfIkj2CKLtCvsHJ7c-tI_-4_tbh_X5-RLfa50Ll7F54nKDp0Re-50y4LBQHoGWxjTKan9Ql6IMxbxsMTsQf65DR_40U7XbJJTQeQ-5KQN3KJmfb750tR0qDukyhOb2-biW2rL2Mbd5hvP_IoG2Mn8M4bb3qOpBtQmJeTxoUJ25DnJhhCGe4bK-TrXDauHtx5; BCLID_BFESS=11157415508952475120; BDSFRCVID_BFESS=YiuOJexroG38bzJevE5BMBPcTOqMFyTTDYLEJs2qYShnrsPVJeC6EG0PtoWQkz--EHtdogKKBmOTHgKF_2uxOjjg8UtVJeC6EG0Ptf8g0M5; H_BDCLCKID_SF_BFESS=tR3aQ5rtKRTffjrnhPF3KhDfXP6-hnjy3bAO3tFa54QpHRcELl3j3M4LXtj8Lp3RymJJ2-39LPO2hpRjyxv4y4Ldj4oxJpOJaavIB-FEHl51fbbvbURvL4ug3-7MBM5dtjTO2bc_5KnlfMQ_bf--QfbQ0hOhqP-jBRIEoCvt-5rDHJTg5DTjhPrM3RjdWMT-MTryKK8yKtFhetQHjf5YLl8S3-nDWx58QNnRhlR2B-3iV-OxDUvnyxAZyxomtfQxtNRJWM3l2-FVKq5S5-OobUPULxc9LUvMW2cdot5yBbc8eIna5hjkbfJBQttjQn3hfIkj2CKLtCvsHJ7c-tI_-4_tbh_X5-RLfa50Ll7F54nKDp0Re-50y4LBQHoGWxjTKan9Ql6IMxbxsMTsQf65DR_40U7XbJJTQeQ-5KQN3KJmfb750tR0qDukyhOb2-biW2rL2Mbd5hvP_IoG2Mn8M4bb3qOpBtQmJeTxoUJ25DnJhhCGe4bK-TrXDauHtx5; BDUSS=EgtYkpkdHRPRmNHSE9hTUlXdzZSTEo2N1FvUzFFd1JrTXVzYXV6N0VYQU9UZTFnRUFBQUFBJCQAAAAAAQAAAAEAAAAP3ewBc25vd2xpZmVzcwAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA7AxWAOwMVga; BDUSS_BFESS=EgtYkpkdHRPRmNHSE9hTUlXdzZSTEo2N1FvUzFFd1JrTXVzYXV6N0VYQU9UZTFnRUFBQUFBJCQAAAAAAQAAAAEAAAAP3ewBc25vd2xpZmVzcwAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA7AxWAOwMVga; Hm_lvt_4aadd610dfd2f5972f1efee2653a2bc5=1623571282,1623571295,1623572498; Hm_lpvt_4aadd610dfd2f5972f1efee2653a2bc5=1623572498; ab_sr=1.0.1_N2JmMjdkMDQ4YjhmOTZjNzY0MWFhZDU4ODU0ZDQ2NzgzZDAxODZmMWVkNGNmYWNjYTIxMjY0NGYzMWU5ZDA0MDZlNmVmODBlOWJkZGE3M2M1YTllYzA1MGVkMTQ2OTRkMDYwMTI2OThmYTJmMDEyZjk0ZjY0MjY4YjhlNmE3ZTUxNDU2MDMzNGIyNzQ2ZmFkZDM4ODVmYmQ5ZTcxNTFkMg==; reptileData=%7B%22data%22%3A%22b63c3c44ce7bc20eda633b56a7a8001dd67cef3dba2333c93cda863c2fdf2fb5d9e24be71639bdeb4dc0343566aef2c9e23a0318e7b5031322b35e380f87464fbd2c17a9a1ced8623fca3edcebaffd6a6b0b671f5faf3dfe9a56f8c9f7e0c6550289a890ebc252822d02af6411c79d729c53e4334fa15b6100077783e37fade1%22%2C%22key_id%22%3A%2230%22%2C%22sign%22%3A%22f18c8fe9%22%7D'
}


# 第二步：取出数据
# 使用request的get 请求，把数据拿出来
response = requests.get(base_url,headers=headers) # 第一次请求
print(response.status_code) # 打印出来的结果是200，否则爬取数据失败

# 把爬到的数据用json格式显示
data = response.text # 文本格式（json）
print(data) # 打印出来的结果与Request URL中链接结果的json数据相同


# 第三步：json格式的数据解析
# json.loads -- 将json编码的字符串转换为一个python数据结构
# json.dump -- 将python数据结构转换为json
json_data = json.loads(data)
print(json_data)
# 有顺序的放入嵌套结构中的key值
json_list = json_data['data']['response']['videos']
print(json_list)

# 使用for循环，将每一个值分别打印出来
for data in json_list:
    # 预处理
    # 视频名称
    video_title = data['title'] + '.mp4'
    # 视频链接
    video_url= data['play_url']
    print(video_title,video_url)
    print("正在下载：",video_title)
    # 第二次请求
    video_data = requests.get(video_url,headers=headers).content # content返回的是二进制的值
    # 保存视频到本地
    with open(r'./视频/' + video_title,'wb') as f:
        f.write(video_data)
        print("下载完成！\n")

运行后的结果

代码解析

通过把json数据转为python数据结构，从而找到值，根据嵌套结构把值取出来

由图可知，有三层嵌套结构
所以有代码：

# 第三步：json格式的数据解析
# json.loads -- 将json编码的字符串转换为一个python数据结构
# json.dump -- 将python数据结构转换为json
json_data = json.loads(data)
print(json_data)
# 有顺序的放入嵌套结构中的key值
json_list = json_data['data']['response']['videos']

使用for循环去遍历每一个视频的值（视频名称、视频链接）

# 使用for循环，将每一个值分别打印出来
for data in json_list:
    # 预处理
    video_title = data['title'] + '.mp4'
    video_url= data['play_url']

打印结果

点击链接可以在浏览器中播放视频

反反爬

有一些网站有反爬机制，这时候我们就会用到反爬机制

1. 找到cookie、User-Agent、Referer的值
   

2. 反反爬的代码

# 反反爬
headers = {
     
    # User-Agent的值 -- 是一种向访问网站提供你所使用的浏览器类型、操作系统及版本、CPU 类型、浏览器渲染引擎、浏览器语言、浏览器插件等信息的标识。UA字符串在每次浏览器 HTTP 请求时发送到服务器！
    'user-agent':'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/89.0.4389.128 Safari/537.36',
    # Referer的值 -- 用于判断你是从哪个页面跳过来的
    'referer':'https://haokan.baidu.com/?fr=pc_pz',
    # Cookie的值 --  用于判断是否你登录（如果没有登录，是没有cookie的）
    'cookie':'BIDUPSID=05FEFAC34AEB974EB63623DBB54F3765; PSTM=1590673047; __yjs_duid=1_223b526dd2e6b4ea4aa28b6a28e3398a1618362899184; BAIDUID=05FEFAC34AEB974EF3880088E7AC8536:SL=0:NR=10:FG=1; BAIDUID_BFESS=05FEFAC34AEB974EF3880088E7AC8536:SL=0:NR=10:FG=1; BDRCVFR[w-kNo__JL0t]=1jmUUpB1KcCmh7GmLNEmi4WUvY; delPer=0; PSINO=1; H_PS_PSSID=34099_31253_33848_33607_34094_26350; BA_HECTOR=a1aha4052hakah804b1gcbeil0q; BDORZ=B490B5EBF6F3CD402E515D22BCDA1598; BDRCVFR[fb3VbsUruOn]=rJZwba6_rOCfAF9pywd; BCLID=11157415508952475120; BDSFRCVID=YiuOJexroG38bzJevE5BMBPcTOqMFyTTDYLEJs2qYShnrsPVJeC6EG0PtoWQkz--EHtdogKKBmOTHgKF_2uxOjjg8UtVJeC6EG0Ptf8g0M5; H_BDCLCKID_SF=tR3aQ5rtKRTffjrnhPF3KhDfXP6-hnjy3bAO3tFa54QpHRcELl3j3M4LXtj8Lp3RymJJ2-39LPO2hpRjyxv4y4Ldj4oxJpOJaavIB-FEHl51fbbvbURvL4ug3-7MBM5dtjTO2bc_5KnlfMQ_bf--QfbQ0hOhqP-jBRIEoCvt-5rDHJTg5DTjhPrM3RjdWMT-MTryKK8yKtFhetQHjf5YLl8S3-nDWx58QNnRhlR2B-3iV-OxDUvnyxAZyxomtfQxtNRJWM3l2-FVKq5S5-OobUPULxc9LUvMW2cdot5yBbc8eIna5hjkbfJBQttjQn3hfIkj2CKLtCvsHJ7c-tI_-4_tbh_X5-RLfa50Ll7F54nKDp0Re-50y4LBQHoGWxjTKan9Ql6IMxbxsMTsQf65DR_40U7XbJJTQeQ-5KQN3KJmfb750tR0qDukyhOb2-biW2rL2Mbd5hvP_IoG2Mn8M4bb3qOpBtQmJeTxoUJ25DnJhhCGe4bK-TrXDauHtx5; BCLID_BFESS=11157415508952475120; BDSFRCVID_BFESS=YiuOJexroG38bzJevE5BMBPcTOqMFyTTDYLEJs2qYShnrsPVJeC6EG0PtoWQkz--EHtdogKKBmOTHgKF_2uxOjjg8UtVJeC6EG0Ptf8g0M5; H_BDCLCKID_SF_BFESS=tR3aQ5rtKRTffjrnhPF3KhDfXP6-hnjy3bAO3tFa54QpHRcELl3j3M4LXtj8Lp3RymJJ2-39LPO2hpRjyxv4y4Ldj4oxJpOJaavIB-FEHl51fbbvbURvL4ug3-7MBM5dtjTO2bc_5KnlfMQ_bf--QfbQ0hOhqP-jBRIEoCvt-5rDHJTg5DTjhPrM3RjdWMT-MTryKK8yKtFhetQHjf5YLl8S3-nDWx58QNnRhlR2B-3iV-OxDUvnyxAZyxomtfQxtNRJWM3l2-FVKq5S5-OobUPULxc9LUvMW2cdot5yBbc8eIna5hjkbfJBQttjQn3hfIkj2CKLtCvsHJ7c-tI_-4_tbh_X5-RLfa50Ll7F54nKDp0Re-50y4LBQHoGWxjTKan9Ql6IMxbxsMTsQf65DR_40U7XbJJTQeQ-5KQN3KJmfb750tR0qDukyhOb2-biW2rL2Mbd5hvP_IoG2Mn8M4bb3qOpBtQmJeTxoUJ25DnJhhCGe4bK-TrXDauHtx5; BDUSS=EgtYkpkdHRPRmNHSE9hTUlXdzZSTEo2N1FvUzFFd1JrTXVzYXV6N0VYQU9UZTFnRUFBQUFBJCQAAAAAAQAAAAEAAAAP3ewBc25vd2xpZmVzcwAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA7AxWAOwMVga; BDUSS_BFESS=EgtYkpkdHRPRmNHSE9hTUlXdzZSTEo2N1FvUzFFd1JrTXVzYXV6N0VYQU9UZTFnRUFBQUFBJCQAAAAAAQAAAAEAAAAP3ewBc25vd2xpZmVzcwAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA7AxWAOwMVga; Hm_lvt_4aadd610dfd2f5972f1efee2653a2bc5=1623571282,1623571295,1623572498; Hm_lpvt_4aadd610dfd2f5972f1efee2653a2bc5=1623572498; ab_sr=1.0.1_N2JmMjdkMDQ4YjhmOTZjNzY0MWFhZDU4ODU0ZDQ2NzgzZDAxODZmMWVkNGNmYWNjYTIxMjY0NGYzMWU5ZDA0MDZlNmVmODBlOWJkZGE3M2M1YTllYzA1MGVkMTQ2OTRkMDYwMTI2OThmYTJmMDEyZjk0ZjY0MjY4YjhlNmE3ZTUxNDU2MDMzNGIyNzQ2ZmFkZDM4ODVmYmQ5ZTcxNTFkMg==; reptileData=%7B%22data%22%3A%22b63c3c44ce7bc20eda633b56a7a8001dd67cef3dba2333c93cda863c2fdf2fb5d9e24be71639bdeb4dc0343566aef2c9e23a0318e7b5031322b35e380f87464fbd2c17a9a1ced8623fca3edcebaffd6a6b0b671f5faf3dfe9a56f8c9f7e0c6550289a890ebc252822d02af6411c79d729c53e4334fa15b6100077783e37fade1%22%2C%22key_id%22%3A%2230%22%2C%22sign%22%3A%22f18c8fe9%22%7D'
}