爬虫框架scrapy

-mongodb
        -操作
    -scrapy
        -安装
            -pip3 install scrapy
                -先装Twisted
                -装pywin32
        -新建项目
            -scrapy startproject 项目名字
        -新建爬虫切换到你创建的项目下
            -scrapy genspider cnblogs www.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
            -settings.py
                -配置文件
            -scrapy.cfg
                -部署相关
        -运行爬虫
            -scrapy crawl cnblogs --nolog

创建好的项目spiders下的app

# -*- coding: utf-8 -*-
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)

添加main方法每次在黑窗口启动比较麻烦

from scrapy.cmdline import execute
# execute(['scrapy', 'crawl', 'cnblogs','--nolog'])
execute(['scrapy', 'crawl', 'cnblogs'])

这里不要禁用log,因为这是唯一的错误显示