20-爬虫之scrapy框架CrawlSpider07

CrawlSpider

是Spider的一个子类，Spider是爬虫文件中的爬虫父类
- 之类的功能一定是对于父类

作用：被作用于专业实现全站数据爬取
- 将一个页面下的所有页码对应的数据进行爬取
基本使用
- 创建一个爬虫工程：scrapy startproject proName
- 进入工程创建一个基于CrawlSpider的爬虫文件
  - scrapy genspider -t crawl spiderName www.xxx.com
- 执行工程：scrapy crawl spiderName

注意

一个链接提取器对应一个规则解析器（多个链接提取器和多个规则解析器）
在实现深度爬取的过程中，需要和scrapy.Request（）结合使用
link = LinkExtractor(allow=r’’)# allow是空follow是True那么我们就能取出全站所有链接

普通爬取

爬虫源码

import scrapy
from scrapy.linkextractors import LinkExtractor
from scrapy.spiders import CrawlSpider, Ruleclass TestSpider(CrawlSpider):name = 'test'#allowed_domains = ['www.xxx.com']start_urls = ['http://www.521609.com/daxuemeinv/']# 链接提取器：根据指定规则（allow参数）在页面中进行链接（url）提取# allow = "正则"：提取链接的规则link = LinkExtractor(allow=r'list8\d+\.html')# 实例化LinkExtractor对象# link = LinkExtractor(allow=r'')# allow是空follow是True那么我们就能取出全站所有链接rules = (# 是实例化一个Rule对象#规则解析器:接收链接提取器提取到的链接，对其发起请求，然后根据指定规则（callback）解析数据Rule(link, callback='parse_item', follow=True),)# follow = True# 将链接提取器，继续作用到链接 提取器提取到的页码所对应的页面中def parse_item(self, response):print(response)# 基于response实现数据解析

深度爬取

CrawlSpider实现深度爬取

通用方式：CrawlSpider + Spider实现深度爬取
创建一个爬虫工程：scrapy startproject proName
进入工程创建一个基于CrawlSpider的爬虫文件
- scrapy genspider -t crawl spiderName www.xxx.com
执行工程：scrapy crawl spiderName

settings.py

# Scrapy settings for sunPro project
#
# For simplicity, this file contains only settings considered important or
# commonly used. You can find more settings consulting the documentation:
#
#     https://docs.scrapy.org/en/latest/topics/settings.html
#     https://docs.scrapy.org/en/latest/topics/downloader-middleware.html
#     https://docs.scrapy.org/en/latest/topics/spider-middleware.htmlBOT_NAME = 'sunPro'SPIDER_MODULES = ['sunPro.spiders']
NEWSPIDER_MODULE = 'sunPro.spiders'# Crawl responsibly by identifying yourself (and your website) on the user-agent
USER_AGENT = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/81.0.4044.138 Safari/537.36"# Obey robots.txt rules
ROBOTSTXT_OBEY = False
LOG_LEVEL = "ERROR"
# Configure maximum concurrent requests performed by Scrapy (default: 16)
#CONCURRENT_REQUESTS = 32# Configure a delay for requests for the same website (default: 0)
# See https://docs.scrapy.org/en/latest/topics/settings.html#download-delay
# See also autothrottle settings and docs
#DOWNLOAD_DELAY = 3
# The download delay setting will honor only one of:
#CONCURRENT_REQUESTS_PER_DOMAIN = 16
#CONCURRENT_REQUESTS_PER_IP = 16# Disable cookies (enabled by default)
#COOKIES_ENABLED = False# Disable Telnet Console (enabled by default)
#TELNETCONSOLE_ENABLED = False# Override the default request headers:
#DEFAULT_REQUEST_HEADERS = {#   'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
#   'Accept-Language': 'en',
#}# Enable or disable spider middlewares
# See https://docs.scrapy.org/en/latest/topics/spider-middleware.html
#SPIDER_MIDDLEWARES = {#    'sunPro.middlewares.SunproSpiderMiddleware': 543,
#}# Enable or disable downloader middlewares
# See https://docs.scrapy.org/en/latest/topics/downloader-middleware.html
#DOWNLOADER_MIDDLEWARES = {#    'sunPro.middlewares.SunproDownloaderMiddleware': 543,
#}# Enable or disable extensions
# See https://docs.scrapy.org/en/latest/topics/extensions.html
#EXTENSIONS = {#    'scrapy.extensions.telnet.TelnetConsole': None,
#}# Configure item pipelines
# See https://docs.scrapy.org/en/latest/topics/item-pipeline.html
ITEM_PIPELINES = {'sunPro.pipelines.SunproPipeline': 300,
}# Enable and configure the AutoThrottle extension (disabled by default)
# See https://docs.scrapy.org/en/latest/topics/autothrottle.html
#AUTOTHROTTLE_ENABLED = True
# The initial download delay
#AUTOTHROTTLE_START_DELAY = 5
# The maximum download delay to be set in case of high latencies
#AUTOTHROTTLE_MAX_DELAY = 60
# The average number of requests Scrapy should be sending in parallel to
# each remote server
#AUTOTHROTTLE_TARGET_CONCURRENCY = 1.0
# Enable showing throttling stats for every response received:
#AUTOTHROTTLE_DEBUG = False# Enable and configure HTTP caching (disabled by default)
# See https://docs.scrapy.org/en/latest/topics/downloader-middleware.html#httpcache-middleware-settings
#HTTPCACHE_ENABLED = True
#HTTPCACHE_EXPIRATION_SECS = 0
#HTTPCACHE_DIR = 'httpcache'
#HTTPCACHE_IGNORE_HTTP_CODES = []
#HTTPCACHE_STORAGE = 'scrapy.extensions.httpcache.FilesystemCacheStorage'

items.py

# Define here the models for your scraped items
#
# See documentation in:
# https://docs.scrapy.org/en/latest/topics/items.htmlimport scrapyclass SunproItem(scrapy.Item):title = scrapy.Field()status = scrapy.Field()class SunProItemDetail(scrapy.Item):content = scrapy.Field()

pipelines.py

# Define your item pipelines here
#
# Don't forget to add your pipeline to the ITEM_PIPELINES setting
# See: https://docs.scrapy.org/en/latest/topics/item-pipeline.html# useful for handling different item types with a single interface
from itemadapter import ItemAdapterclass SunproPipeline:def process_item(self, item, spider):if item.__class__.__name__=='SunproItem':title = item['title']status = item['status']print(title+":"+status)else:content = item['content']print(content)return item

sun.py 爬虫源文件

此方法进行数据爬取，，持久化存储目前无法将title和content进行一一匹配，我们需要手动发起请求

import scrapy
from scrapy.linkextractors import LinkExtractor
from scrapy.spiders import CrawlSpider, Rule
from sunPro.items import SunproItem,SunProItemDetailclass TestSpider(CrawlSpider):name = 'sun'#allowed_domains = ['www.xxx.com']start_urls = ['http://wz.sun0769.com/political/index/politicsNewest?id=1&page=1']# 链接提取器：根据指定规则（allow参数）在页面中进行链接（url）提取# allow = "正则"：提取链接的规则link = LinkExtractor(allow=r'id=1&page=\d+')# 实例化LinkExtractor对象link_detail = LinkExtractor(allow=r'dindex\?id=\d+') #详情页url# link = LinkExtractor(allow=r'')# allow是空follow是True那么我们就能取出全站所有链接rules = (# 是实例化一个Rule对象#规则解析器:接收链接提取器提取到的链接，对其发起请求，然后根据指定规则（callback）解析数据Rule(link, callback='parse_item', follow=True),Rule(link_detail, callback='parse_detail'),)# follow = True# 将链接提取器，继续作用到链接 提取器提取到的页码所对应的页面中#标题&状态def parse_item(self, response):li_list = response.xpath('/html/body/div[2]/div[3]/ul[2]/li')for li in li_list:title = li.xpath('./span[3]/a/text()').extract_first()status = li.xpath('./span[2]/text()').extract_first()item = SunproItem()item['title']=titleitem['status'] =statusyield item# 实现深度爬取：爬取详情页中的数据# 1，对详情页的url进行捕获# 2，对详情页的url发起请求获取数据def parse_detail(self,response):content = response.xpath('/html/body/div[3]/div[2]/div[2]/div[2]/pre/text()').extract_first()item = SunProItemDetail()item['content']=contentyield item# 爬虫文件会向管道提交两个不同形式的item，管道会接受到两个不同形式的item。#我们需要在管道中判断接收到item到底是哪一个#此方法进行数据爬取，，持久化存储目前无法将title和content进行一一匹配，我们需要手动发起请求

CrawlSpider+Spider全站深度爬取

items.py

# Define here the models for your scraped items
#
# See documentation in:
# https://docs.scrapy.org/en/latest/topics/items.htmlimport scrapyclass SunproItem(scrapy.Item):title = scrapy.Field()status = scrapy.Field()content = scrapy.Field()

pipelines.py

# Define your item pipelines here
#
# Don't forget to add your pipeline to the ITEM_PIPELINES setting
# See: https://docs.scrapy.org/en/latest/topics/item-pipeline.html# useful for handling different item types with a single interface
from itemadapter import ItemAdapterclass SunproPipeline:def process_item(self, item, spider):print(item)return item

sun.py 爬虫源文件

import scrapy
from scrapy.linkextractors import LinkExtractor
from scrapy.spiders import CrawlSpider, Rule
from sunPro.items import SunproItemclass TestSpider(CrawlSpider):name = 'sun'#allowed_domains = ['www.xxx.com']start_urls = ['http://wz.sun0769.com/political/index/politicsNewest?id=1&page=1']# 链接提取器：根据指定规则（allow参数）在页面中进行链接（url）提取# allow = "正则"：提取链接的规则link = LinkExtractor(allow=r'id=1&page=\d+')# 实例化LinkExtractor对象#link_detail = LinkExtractor(allow=r'dindex\?id=\d+') #详情页urlrules = (# 是实例化一个Rule对象#规则解析器:接收链接提取器提取到的链接，对其发起请求，然后根据指定规则（callback）解析数据Rule(link, callback='parse_item', follow=True),# Rule(link_detail, callback='parse_detail'),)# #follow = True# 将链接提取器，继续作用到链接 提取器提取到的页码所对应的页面中#标题&状态def parse_item(self, response):li_list = response.xpath('/html/body/div[2]/div[3]/ul[2]/li')for li in li_list:title = li.xpath('./span[3]/a/text()').extract_first()status = li.xpath('./span[2]/text()').extract_first()detail_url ="http://wz.sun0769.com" + li.xpath('./span[3]/a/@href').extract_first()#详情页urlitem = SunproItem()item['title'] = titleitem['status'] = statusyield scrapy.Request(url=detail_url,callback=self.parse_detail,meta={'item':item})def parse_detail(sele,response):content = response.xpath('/html/body/div[3]/div[2]/div[2]/div[2]/pre/text()').extract_first()item = response.meta['item']item['content'] = contentyield item

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20-爬虫之scrapy框架CrawlSpider07

CrawlSpider

注意

普通爬取

爬虫源码

深度爬取

settings.py

items.py

pipelines.py

sun.py 爬虫源文件

CrawlSpider+Spider全站深度爬取

items.py

pipelines.py

sun.py 爬虫源文件

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