爬虫scrapy框架

Scrapt框架安装

# 下载过程
pip3 install scrapy
# mac本基本可以直接安装成功
# windows可能会出现错误
报错处理：

"""
报错：
     error: Microsoft Visual C++ 14.0 or greater is required. Get it with "Micros
oft C++ Build Tools": https://visualstudio.microsoft.com/visual-cpp-build-tools/

    ----------------------------------------
ERROR: Command errored out with exit status 1: 'C:ProgramDataAnaconda3python.
exe' -u -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'C:\Users\chun
_xiong\AppData\Local\Temp\pip-install-t2sgma8_\twisted\setup.py'"'"'; __fi
le__='"'"'C:\Users\chun_xiong\AppData\Local\Temp\pip-install-t2sgma8_\twi
sted\setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.r
ead().replace('"'"'
'"'"', '"'"'
'"'"');f.close();exec(compile(code, __file_
_, '"'"'exec'"'"'))' install --record 'C:Userschun_xiongAppDataLocalTemppi
p-record-tibwu8ifinstall-record.txt' --single-version-externally-managed --comp
ile --install-headers 'C:ProgramDataAnaconda3IncludeTwisted' Check the logs
for full command output.
"""
# 处理方法
1.pip3 install wheel
2.http://www.lfd.uci.edu/~gohlke/pythonlibs/#twisted  #根据解释器版本下载对应的依赖文件
3.利用pip报错确定上述下载文件的位置
    C:Users用户名
    pip3 install Twisted-20.3.0-cp38-cp38-win_amd64.whl
4.pip3 install pywin32
5.pip3 install scrapy
'''pip版本过低可能也会报错，根据报错命令更新pip即可'''

# 验证是否安装成功
scrapy

scrapt基本使用

# 命令行创建项目
    scrapy startproject 项目名字
例如：scrapy startproject papa

# 新建爬虫
    scrapy genspider 爬虫名 爬取的域名
例如：scrapy genspider cnblogs cnblogs.com

        -项目目录介绍
            -spiders
                -所有的爬虫程序
            -items.py
                -类似于django的model类
            -middlewares.py
                -中间件
            -pipelines.py
                -持久化相关(数据存储)
            -settings.py
                -配置文件(关注:爬虫协议)
            -scrapy.cfg
                -部署相关
        -运行爬虫
            -scrapy crawl 文件名 --nolog
            
        -爬取数据
        
        //*[@id="post_list"]/div[1]
        
https://www.cnblogs.com/xiaoyuanqujing/protected/articles/11805810.html

爬取博客园首页文章

cnblogs.py中代码
import scrapy

from scrapy import Request
class CnblogsSpider(scrapy.Spider):
    name = 'cnblogs'   #爬虫名，必须唯一
    allowed_domains = ['cnblogs.com']   #允许的域名，
    start_urls = ['https://www.cnblogs.com/']  #起始的url
    #深度优先，广度优先
    #爬虫去重：好多策略
    #爬虫起始入口 start_requests
    def parse_detail(self,response):
        print(len(response.text))


    def parse(self, response):
        # print('--------4444-------',response)
        # print(response.text)
        #混搭
        # from  bs4 import BeautifulSoup
        # soup=BeautifulSoup(response.text,"lxml")
        # soup.find(name='div')
        #解析
        div_list=response.css('.post_item')  #取出class为post_item的所有
        # print(len(div_list))
        #//a[contains(@class,"li")]
        # div_list=response.xpath('//div[contains(@class,"post_item")]')
        # div_list=response.xpath('//*[@id="post_list"]/div')
        # print(len(div_list))
        for div in div_list:
            #extract_first()表示取列表中的第一个
            url=div.css('.post_item_body a::attr(href)').extract_first()
            print(url)
            yield Request(url,callback=self.parse_detail)
        next_url=response.css('.pager a:last-child::attr(href)').extract_first()
        print('https://www.cnblogs.com'+next_url)
        yield Request('https://www.cnblogs.com'+next_url)

# 新增main.py

from scrapy.cmdline import execute

execute(['scrapy', 'crawl', 'cnblogs','--nolog'])