一、xpath提取数据

<bookstore>
<book category="Python 基础">
    <title lang="cn">cook book</title>
    <author>David Beazley</author>
    <year>2022</year>
    <price>53.20</price>
</book>
<book category="story book">
    <title lang="en">The Lord of the Rings</title>
    <author>J.R.R.托尔金</author>
    <year>2005</year>
    <price>29.99</price>
</book>
<book category="WEB">
    <title lang="en">Learning XML</title>
    <author>Erik T. Ray</author>
    <year>2013</year>
    <price>40.05</price>
</book>
</bookstore>

xpath（XML Path Language）是在HTML\XML中查找信息的语句，可在HTML\XML文档中对元素和属性进行遍历

在根结点下面的节点是并列的，如一个树结构，我们也可以像访问文件一样来获得这个元素

xpath插件的安装：

自备梯子（能直接找到国内的.crx插件也可以不挂梯子）
google浏览器搜索xpath_helper，进入谷歌应用商店下载得到一个.crx后缀的文件
打开浏览器的设置，找到拓展（拓展程序），进入开发者模式
直接下载得到的.crx文件用鼠标拖入浏览器，选择安装拓展
点击浏览器右上角拓展程序图标，可将xpath插件锁定

点击xpath图标，出现这个黑框代表xpath插件安装成功

xpath节点选取：

nodename ：选中该元素
/ ：元素间的层级过度
// ：匹配选择，可省略中间节点而不考虑位置
@ ：选取属性
text() ：选取文本

lxml模块：

lxml模块是Python的第三方库，配合path，利用etree.HTML，将获取的网页字符串转化成Element对象，Element对象通过xpath的方法调用，以列表形式返回数据，再进行数据提取

import requests
from lxml import etree

text = """
<bookstore>
<book category="Python 基础">
    <title lang="cn">cook book</title>
    <author>David Beazley</author>
    <year>2022</year>
    <price>53.20</price>
</book>
<book category="story book">
    <title lang="en">The Lord of the Rings</title>
    <author>J.R.R.托尔金</author>
    <year>2005</year>
    <price>29.99</price>
</book>
<book category="WEB">
    <title lang="en">Learning XML</title>
    <author>Erik T. Ray</author>
    <year>2013</year>
    <price>40.05</price>
</book>
</bookstore>
"""

html = etree.HTML(text)
print(type(html))   # <class 'lxml.etree._Element'>
html_str = etree.tostring(html).decode()
print(type(html_str))   # <class 'str'>

# 获取书名
book_name = html.xpath("/html/body/bookstore/book/title/text()")    # 绝对路径
print(book_name)    # ['cook book', 'The Lord of the Rings', 'Learning XML']
book_name = html.xpath("//title/text()")
print(book_name)    # ['cook book', 'The Lord of the Rings', 'Learning XML']

# 数据提取列表元素
for i in book_name:
    print(i, end="\t")
# cook book	The Lord of the Rings	Learning XML

# 获取作者
book_author = html.xpath("//author/text()")
print("\n", book_author)    # ['David Beazley', 'J.R.R.托尔金', 'Erik T. Ray']

# 获取参数
category = html.xpath("//book/@category")
print(category)     # ['Python 基础', 'story book', 'WEB']
lang = html.xpath("//book/title/@lang")
print(lang)         # ['cn', 'en', 'en']

book = html.xpath("//book")
for i in book:
    category = i.xpath("@category")[0]
    book_info = dict()
    book_info[category] = dict()
    book_info[category]['name'] = i.xpath("title/text()")[0]
    book_info[category]['author'] = i.xpath("author/text()")[0]
    book_info[category]['year'] = i.xpath("year/text()")[0]
    book_info[category]['price'] = i.xpath("price/text()")[0]
    print(book_info)

"""
{'Python 基础': {'name': 'cook book', 'author': 'David Beazley', 'year': '2022', 'price': '53.20'}}
{'story book': {'name': 'The Lord of the Rings', 'author': 'J.R.R.托尔金', 'year': '2005', 'price': '29.99'}}
{'WEB': {'name': 'Learning XML', 'author': 'Erik T. Ray', 'year': '2013', 'price': '40.05'}}
"""

二、爬虫爬取图片资源

注：本代码爬取的图片皆无任何商业目的，仅供爬虫技术学习使用

示例：王者荣耀全英雄皮肤图片

import requests
from lxml import etree
import re

url = "https://pvp.qq.com/web201605/herolist.shtml"
response = requests.get(url)

response.encoding = "gbk"
html = response.text
# print(html)

html = etree.HTML(html)
# li_list = html.xpath("/html/body/div[3]/div/div/div[2]/div[2]/ul")
li_list = html.xpath('//ul[@class="herolist clearfix"]/li/a')
# xpath_helper拿到的xpath是已经被前端渲染过了的，不一定可用
# 如果xpath拿到的xpath不能直接用，就通过标签和属性手动选择数据

print(len(li_list))     # 93，英雄数量
for i in li_list:
    href = i.xpath('./@href')[0]
    name = i.xpath('./img/@alt')[0]
    # print(href, name)
    pattern = r'herodetail/(\d*)\.shtml'
    id = re.search(pattern, href).group(1)
    # print(name, id)

    cnt = 1
    while True:
        try:
            url = f"https://game.gtimg.cn/images/yxzj/img201606/skin/hero-info/{id}/{id}-bigskin-{cnt}.jpg"
            resp = requests.get(url)
            if resp.status_code != 200:
                break
            with open(f"./skins/{name}{cnt}.jpg", "wb") as f:
                f.write(resp.content)
            cnt += 1
        except:
            print(Exception)
            break

三、爬虫爬取视频资源

注：本代码爬取的视频无任何商业目的，仅供爬虫技术学习使用

示例：B站李知恩视频

1. 对网页发送网络请求

import requests
from lxml import etree

url = "https://search.bilibili.com/all?" \
      "vt=16780856&keyword=李知恩&from_source=webtop_search&spm_id_from=333.1007&search_source=5"

response = requests.get(url)
print(response.text)

观察响应结果，请求发送成功，但是并未拿到想要的前端代码，提示需要验证码（登录）

登录信息在请求头里面，我们要获取请求头信息

2. 获取视频链接

import requests
from lxml import etree

url = "https://search.bilibili.com/all?" \
      "vt=16780856&keyword=李知恩&from_source=webtop_search&spm_id_from=333.1007&search_source=5"

header = {
    'user-agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/110.0.0.0 Safari/537.36',
    'referer': 'https://search.bilibili.com/all?keyword=%E6%9D%8E%E7%9F%A5%E6%81%A9&from_source=webtop_search&spm_id_from=333.1007&search_source=5',
    'cookie': "buvid3=EE26C87B-4D71-DDB1-E3EF-7C231D141FDE66254infoc; b_nut=1676099166; i-wanna-go-back=-1; _uuid=EEA6D79B-8E44-283C-4B1A-F63391023FC41071505infoc; buvid4=8BD6A57D-1756-0D2F-2D58-824CE069B0CF82025-023021115-3r0csnyFmYTJnqj7nA8pAw%3D%3D; DedeUserID=703170552; DedeUserID__ckMd5=921efa783160cc40; rpdid=|(YumR|Yk)|0J'uY~Y|mmklY; b_ut=5; nostalgia_conf=-1; header_theme_version=CLOSE; buvid_fp_plain=undefined; hit-dyn-v2=1; CURRENT_BLACKGAP=0; CURRENT_FNVAL=4048; CURRENT_QUALITY=116; LIVE_BUVID=AUTO5716781015889927; hit-new-style-dyn=1; CURRENT_PID=114c35b0-cd23-11ed-a99d-39a1565dc8a4; fingerprint=07652cefeee9b3af116a4e8892842b91; home_feed_column=5; FEED_LIVE_VERSION=V8; SESSDATA=4afb5a37%2C1696835970%2Cf0b52%2A42; bili_jct=00e8099da712cb9a9738ad46d90f6d21; sid=8tpyjca9; bp_video_offset_703170552=783637244587016200; is-2022-channel=1; buvid_fp=07652cefeee9b3af116a4e8892842b91; PVID=2; innersign=1; b_lsid=326DE875_18776328C0A"
}

response = requests.get(url, headers=header)
# print(response.text)

html = etree.HTML(response.text)
div_list = html.xpath('//*[@id="i_cecream"]/div/div[2]/div[2]/div/div/div/div[1]/div/div')
print(len(div_list))

for i in div_list:
    i_url = i.xpath('./div/div[2]/a/@href')[0]
    i_url = "https:" + i_url
    print(i_url)

3. 下载第三方包you-get

pip install you-get

4. 用操作系统调用you-get包下载视频资源

import requests
from lxml import etree
import sys
import os
from you_get import common as you_get
import time
import ffmpy

url = "https://search.bilibili.com/all?keyword=%E6%9D%8E%E7%9F%A5%E6%81%A9&from_source=webtop_search&spm_id_from=333.1007&search_source=5"
header = {
    'user-agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/110.0.0.0 Safari/537.36',
    'referer': 'https://search.bilibili.com/all?keyword=%E6%9D%8E%E7%9F%A5%E6%81%A9&from_source=webtop_search&spm_id_from=333.1007&search_source=5',
    'cookie': "buvid3=EE26C87B-4D71-DDB1-E3EF-7C231D141FDE66254infoc; b_nut=1676099166; i-wanna-go-back=-1; _uuid=EEA6D79B-8E44-283C-4B1A-F63391023FC41071505infoc; buvid4=8BD6A57D-1756-0D2F-2D58-824CE069B0CF82025-023021115-3r0csnyFmYTJnqj7nA8pAw%3D%3D; DedeUserID=703170552; DedeUserID__ckMd5=921efa783160cc40; rpdid=|(YumR|Yk)|0J'uY~Y|mmklY; b_ut=5; nostalgia_conf=-1; header_theme_version=CLOSE; buvid_fp_plain=undefined; hit-dyn-v2=1; CURRENT_BLACKGAP=0; CURRENT_FNVAL=4048; CURRENT_QUALITY=116; LIVE_BUVID=AUTO5716781015889927; hit-new-style-dyn=1; CURRENT_PID=114c35b0-cd23-11ed-a99d-39a1565dc8a4; fingerprint=07652cefeee9b3af116a4e8892842b91; home_feed_column=5; FEED_LIVE_VERSION=V8; SESSDATA=4afb5a37%2C1696835970%2Cf0b52%2A42; bili_jct=00e8099da712cb9a9738ad46d90f6d21; sid=8tpyjca9; bp_video_offset_703170552=783637244587016200; is-2022-channel=1; buvid_fp=07652cefeee9b3af116a4e8892842b91; PVID=2; b_lsid=D3D108210E_1877853C1F0; innersign=0"
}

response = requests.get(url, headers=header)
# print(response.text)

html = etree.HTML(response.text)
div_list = html.xpath('//*[@id="i_cecream"]/div/div[2]/div[2]/div/div/div/div[1]/div/div')
print(len(div_list))

path = "iu_video/"

for i in div_list[:5]:
    v_url = i.xpath('.//a/@href')[0]
    v_url = "https:" + v_url
    # print(v_url)
    # v_title = i.xpath('./div/div[2]/a/div/div[1]/picture/img/@alt')
    v_title = (i.xpath('.//a/div/div[1]/picture//@alt')[0])
    print(v_url, v_title)
    try:
        # sys.argv = ['you-get', '-o', path, v_url]
        # you_get.main()
        os.system(f'you-get -o {path} {v_url}')
        print(v_url, "下载成功")
    except:
        print(Exception)
        print(v_url, v_title, "下载失败")
    else:
        time.sleep(2)

爬取到的资源包括XML类型文件和FLV类型文件，XML类型文件是弹幕文件，FLY类型文件是视频文件，特定播放器可以直接播放，我们也可以将其转换为mp4文件

四、FLV文件转码为MP4文件

安装ffmpy资源包，找到ffmgep.exe将视频文件转码为mp4文件

pip install ffmpy

import ffmpy
import os

folder_path = "./iu_video/"
for filename in os.listdir(folder_path):
    try:
        if ".flv" in filename:
            filename = folder_path + filename
            sink_file = filename[:-3] + "mp4"
            ff = ffmpy.FFmpeg(
                executable="C:\\Program Files (x86)\\Common Files\DVDVideoSoft\\lib\\ffmpeg.exe",
                inputs={filename: None},
                outputs={sink_file: None}
            )
            ff.run()
            print(filename, "转码成功")
    except:
        print(Exception)
        print(filename, "转码失败")