文章目錄

• 一. CrawlSpider
• 二. CrawlSpider案例
• • 1. 目錄結構
  • 2. wxapp_spider.py
  • 3. items.py
  • 4. pipelines.py
  • 5. settings.py
  • 6. start.py
• 三. 重點總結

一. CrawlSpider

現實情況下，我們需要對滿足某個特定條件的url進行爬取，這時候就可以通過CrawlSpider完成。

CrawlSpider繼承自Spider，只不過在之前的基礎上增加了新的功能，可以定義爬取的url規則，Scrapy碰到滿足條件的url都進行爬取，而不用手動的yield Request。

二. CrawlSpider案例

1. 目錄結構

2. wxapp_spider.py

# -*- coding: utf-8 -*- import scrapy from scrapy.linkextractors import LinkExtractor from scrapy.spiders import CrawlSpider, Rule from wxapp.items import WxappItemclass WxappSpiderSpider(CrawlSpider):name = 'wxapp_spider'allowed_domains = ['wxapp-union.com']start_urls = ['http://www.wxapp-union.com/portal.php?mod=list&catid=1&page=1']rules = (Rule(LinkExtractor(allow=r'.+mod=list&catid=1&page=\d'), follow=True),Rule(LinkExtractor(allow=r'.+article-.+\.html'), callback='parse_detail', follow=False))def parse_detail(self, response):title = response.xpath("//h1[@class='ph']/text()").get()# print(title)author_p = response.xpath(".//p[@class='authors']")author = author_p.xpath("./a/text()").get()pub_time = author_p.xpath("./span/text()").get()# print('author:%s/pub_time:%s'%(author,pub_time))article_content = response.xpath(".//td[@id='article_content']//text()").getall()content = "".join(article_content).strip()# print(content)# print('-'*30)item = WxappItem(title=title,author=author,pub_time=pub_time,content=content)yield item

3. items.py

# -*- coding: utf-8 -*-# Define here the models for your scraped items # # See documentation in: # https://docs.scrapy.org/en/latest/topics/items.htmlimport scrapyclass WxappItem(scrapy.Item):# define the fields for your item here like:title = scrapy.Field()author = scrapy.Field()pub_time = scrapy.Field()content = scrapy.Field()

4. pipelines.py

# -*- coding: utf-8 -*-# 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 from scrapy.exporters import JsonLinesItemExporterclass WxappPipeline(object):def __init__(self):self.fp = open('wxjc.json','wb')self.exporter = JsonLinesItemExporter(self.fp,ensure_ascii=False,encoding='utf-8')def process_item(self, item, spider):self.exporter.export_item(item)return itemdef close_spider(self,spider):self.fp.close()

5. settings.py

# -*- coding: utf-8 -*-# Scrapy settings for wxapp 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 = 'wxapp'SPIDER_MODULES = ['wxapp.spiders'] NEWSPIDER_MODULE = 'wxapp.spiders'# Crawl responsibly by identifying yourself (and your website) on the user-agent #USER_AGENT = 'wxapp (+http://www.yourdomain.com)'# Obey robots.txt rules ROBOTSTXT_OBEY = False# 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 = 1 # 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','User-Agent':'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/73.0.3683.75 Safari/537.36' }# Enable or disable spider middlewares # See https://docs.scrapy.org/en/latest/topics/spider-middleware.html #SPIDER_MIDDLEWARES = { # 'wxapp.middlewares.WxappSpiderMiddleware': 543, #}# Enable or disable downloader middlewares # See https://docs.scrapy.org/en/latest/topics/downloader-middleware.html #DOWNLOADER_MIDDLEWARES = { # 'wxapp.middlewares.WxappDownloaderMiddleware': 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 = {'wxapp.pipelines.WxappPipeline': 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'

6. start.py

from scrapy import cmdlinecmdline.execute("scrapy crawl wxapp_spider".split())

三. 重點總結

總結

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