导览
1.Scrapy install
2.Scrapy 项目创建
3.Scrapy 自定义爬虫类
4.Scrapy 处理逻辑
5.Scrapy 扩展
1. Scrapy install
准备知识
pip 包管理Python 安装XpathCssWindows安装 Scrapy
$>- pip install scrapy
Linux安装 Scrapy
$>- apt-get install python-scrapy
2. Scrapy 项目创建
在开始爬取之前，必须创建一个新的Scrapy项目。进入自定义的项目目录中，运行下列命令：
$>- scrapy startproject mySpider
其中， mySpider 为项目名称，可以看到将会创建一个 mySpider 文件夹，使用命令查看目录结构
$>- tree mySpider
3. Scrapy 自定义爬虫类
通过Scrapy的Spider基础模版顺便建立一个基础的爬虫。（也可以不用Scrapy命令建立基础爬虫，）
$>- scrapy genspider gzrbSpider
scrapy genspider是一个命令，也是scrapy最常用的几个命令之一。至此，一个最基本的爬虫项目已经建立完毕了.
文件描述：
命令描述：
4. Scrapy 处理逻辑
文件 \spiders\gzrbSpider.py
import scrapyfrom mySpider.items import MySpiderItemclass gzrbSpider(scrapy.Spider):name = "gzrbSpider"allowed_domains = ["/"]start_urls = ('',)def parse(self, response):subSelector = response.xpath('.//div[@class="mt35"]//ul[@class="news-list"]')items = []for sub in subSelector:item = MySpiderItem()item['newName'] = sub.xpath('./li/a/text()').extract()items.append(item)return items
文件 Item.py
# Define here the models for your scraped items## See documentation in:# /en/latest/topics/items.htmlimport scrapyclass MySpiderItem(scrapy.Item):# define the fields for your item here like:# name = scrapy.Field()newName = scrapy.Field()
文件 Setting.py
# Scrapy settings for mySpider project## For simplicity, this file contains only settings considered important or# commonly used. You can find more settings consulting the documentation:##/en/latest/topics/settings.html#/en/latest/topics/downloader-middleware.html#/en/latest/topics/spider-middleware.htmlBOT_NAME = 'mySpider'SPIDER_MODULES = ['mySpider.spiders']NEWSPIDER_MODULE = 'mySpider.spiders'# Crawl responsibly by identifying yourself (and your website) on the user-agent#USER_AGENT = 'mySpider(+)'# Obey robots.txt rulesROBOTSTXT_OBEY = True# Configure maximum concurrent requests performed by Scrapy (default: 16)#CONCURRENT_REQUESTS = 32# Configure a delay for requests for the same website (default: 0)# See /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 /en/latest/topics/spider-middleware.html#SPIDER_MIDDLEWARES = {# 'mySpider.middlewares.mySpiderSpiderMiddleware': 543,#}# Enable or disable downloader middlewares# See /en/latest/topics/downloader-middleware.html#DOWNLOADER_MIDDLEWARES = {# 'mySpider.middlewares.mySpiderDownloaderMiddleware': 543,#}# Enable or disable extensions# See /en/latest/topics/extensions.html#EXTENSIONS = {# 'scrapy.extensions.telnet.TelnetConsole': None,#}# Configure item pipelines# See /en/latest/topics/item-pipeline.htmlITEM_PIPELINES = {'mySpider.pipelines.mySpiderPipeline': 300,}# Enable and configure the AutoThrottle extension (disabled by default)# See /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 /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'
文件 pipelines.py
# Define your item pipelines here## Don't forget to add your pipeline to the ITEM_PIPELINES setting# See: /en/latest/topics/item-pipeline.html# useful for handling different item types with a single interfacefrom itemadapter import ItemAdapterimport time# class mySpiderPipeline:#def process_item(self, item, spider):# return itemclass MySpiderPipeline(object):def process_item(self, item, spider):now = time.strftime('%Y-%m-%d', time.localtime())fileName = 'gzrb' + now + '.txt'for it in item['newName ']:with open(fileName,encoding='utf-8',mode = 'a') as fp:# fp.write(item['newName '][0].encode('utf8') + '\n\n')fp.write(it + '\n\n')return item
本文代码结果展示：
5. Scrapy 扩展
Xpath:
Css:
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