crawlSpider全站數據爬取

簡介:

CrawlSpider其實是Spider的一個子類，除了繼承到Spider的特性和功能外，還派生除了其自己獨有的更加強大的特性和功能。其中最顯著的功能就是”LinkExtractors鏈接提取器“。Spider是所有爬蟲的基類，其設計原則只是為了爬取start_url列表中網頁，而從爬取到的網頁中提取出的url進行繼續的爬取工作使用CrawlSpider更合適。

使用:

創建scrapy工程：scrapy startproject projectName

創建爬蟲文件：scrapy genspider -t crawl spiderName www.xxx.com    --此指令對比以前的指令多了 "-t crawl"，表示創建的爬蟲文件是基於CrawlSpider這個類的，而不再是Spider這個基類

爬蟲文件:

import scrapy
from scrapy.linkextractors import LinkExtractor
from scrapy.spiders import CrawlSpider, Rule


class ChoutidemoSpider(CrawlSpider):
    name = 'choutiDemo'
    #allowed_domains = ['www.chouti.com']
    start_urls = ['http://www.chouti.com/']

    rules = (
        Rule(LinkExtractor(allow=r'Items/'), callback='parse_item', follow=True),
    )

    def parse_item(self, response):
        i = {}
        #i['domain_id'] = response.xpath('//input[@id="sid"]/@value').extract()
        #i['name'] = response.xpath('//div[@id="name"]').extract()
        #i['description'] = response.xpath('//div[@id="description"]').extract()
        return i

  - 2，3行：導入CrawlSpider相關模塊

　　- 7行：表示該爬蟲程序是基於CrawlSpider類的

　　- 12，13，14行：表示為提取Link規則

　　- 16行：解析方法

　　CrawlSpider類和Spider類的最大不同是CrawlSpider多了一個rules屬性，其作用是定義”提取動作“。在rules中可以包含一個或多個Rule對象，在Rule對象中包含了LinkExtractor對象。

 LinkExtractor：鏈接提取器

LinkExtractor(

　　　　　　　  allow=r'Items/'，# 滿足括號中“正則表達式”的值會被提取，如果為空，則全部匹配。

　　　　　　　　 deny=xxx,  # 滿足正則表達式的則不會被提取。

 

　　　　　　　　 restrict_xpaths=xxx, # 滿足xpath表達式的值會被提取

　　　　　　　　 restrict_css=xxx, # 滿足css表達式的值會被提取

　　　　　　　　 deny_domains=xxx, # 不會被提取的鏈接的domains。　

　　  )
　　　　- 作用：提取response中符合規則的鏈接。

 Rule : 規則解析器。根據鏈接提取器中提取到的鏈接，根據指定規則提取解析器鏈接網頁中的內容。

 Rule(LinkExtractor(allow=r'Items/'), callback='parse_item', follow=True)

　　　　- 參數介紹：

　　　　　　參數1：指定鏈接提取器

　　　　　　參數2：指定規則解析器解析數據的規則（回調函數）

　　　　　　參數3：是否將鏈接提取器繼續作用到鏈接提取器提取出的鏈接網頁中。當callback為None,參數3的默認值為true。

CrawlSpider整體爬取流程：

a)爬蟲文件首先根據起始url，獲取該url的網頁內容
b)鏈接提取器會根據指定提取規則將步驟a中網頁內容中的鏈接進行提取
c)規則解析器會根據指定解析規則將鏈接提取器中提取到的鏈接中的網頁內容根據指定的規則進行解析
d)將解析數據封裝到item中，然后提交給管道進行持久化存儲

爬取糗事百科糗圖板塊的所有頁碼數據

爬蟲文件

mport scrapy
from scrapy.linkextractors import LinkExtractor
from scrapy.spiders import CrawlSpider, Rule
from qiubaiBycrawl.items import QiubaibycrawlItem
import re
class QiubaitestSpider(CrawlSpider):
    name = 'qiubaiTest'
    #起始url
    start_urls = ['http://www.qiushibaike.com/']

    #定義鏈接提取器，且指定其提取規則
    page_link = LinkExtractor(allow=r'/8hr/page/\d+/')
    
    rules = (
        #定義規則解析器，且指定解析規則通過callback回調函數
        Rule(page_link, callback='parse_item', follow=True),
    )

    #自定義規則解析器的解析規則函數
    def parse_item(self, response):
        div_list = response.xpath('//div[@id="content-left"]/div')
        
        for div in div_list:
            #定義item
            item = QiubaibycrawlItem()
            #根據xpath表達式提取糗百中段子的作者
            item['author'] = div.xpath('./div/a[2]/h2/text()').extract_first().strip('\n')
            #根據xpath表達式提取糗百中段子的內容
            item['content'] = div.xpath('.//div[@class="content"]/span/text()').extract_first().strip('\n')

            yield item #將item提交至管道

item文件

import scrapy


class QiubaibycrawlItem(scrapy.Item):
    # define the fields for your item here like:
    # name = scrapy.Field()
    author = scrapy.Field() #作者
    content = scrapy.Field() #內容

管道文件

class QiubaibycrawlPipeline(object):
    
    def __init__(self):
        self.fp = None
        
    def open_spider(self,spider):
        print('開始爬蟲')
        self.fp = open('./data.txt','w')
        
    def process_item(self, item, spider):
        #將爬蟲文件提交的item寫入文件進行持久化存儲
        self.fp.write(item['author']+':'+item['content']+'\n')
        return item
    
    def close_spider(self,spider):
        print('結束爬蟲')
        self.fp.close()

 爬取boss

爬蟲文件

import scrapy
from scrapy.linkextractors import LinkExtractor
from scrapy.spiders import CrawlSpider, Rule
from bossPro.items import DetailItem,FirstItem
#爬取的是崗位名稱（首頁）和崗位描述(詳情頁)
class BossSpider(CrawlSpider):
    name = 'boss'
    # allowed_domains = ['www.xxx.com']
    start_urls = ['https://www.zhipin.com/c101010100/?query=python%E5%BC%80%E5%8F%91&page=1&ka=page-prev']
    #獲取所有的頁碼連接
    link = LinkExtractor(allow=r'page=\d+')
    link_detail = LinkExtractor(allow=r'/job_detail/.*?html')
    #/job_detail/f2a47b2f40c53bd41XJ93Nm_GVQ~.html
    #/job_detail/47dc9803e93701581XN80ty7GFI~.html
    rules = (
        Rule(link, callback='parse_item', follow=True),
        Rule(link_detail, callback='parse_detail'),
    )
    #將頁碼連接對應的頁面數據中的崗位名稱進行解析
    def parse_item(self, response):
        li_list = response.xpath('//div[@class="job-list"]/ul/li')
        for li in li_list:
            item = FirstItem()
            job_title = li.xpath('.//div[@class="job-title"]/text()').extract_first()
            item['job_title'] = job_title
            # print(job_title)

            yield item
    def parse_detail(self,response):
        job_desc = response.xpath('//*[@id="main"]/div[3]/div/div[2]/div[2]/div[1]/div//text()').extract()
        item = DetailItem()
        job_desc = ''.join(job_desc)
        item['job_desc'] = job_desc

        yield item

items文件

# Define here the models for your scraped items
#
# See documentation in:
# https://doc.scrapy.org/en/latest/topics/items.html

import scrapy


class DetailItem(scrapy.Item):
    # define the fields for your item here like:
    job_desc = scrapy.Field()
class FirstItem(scrapy.Item):
    # define the fields for your item here like:
    job_title = scrapy.Field()

管道文件

# Define your item pipelines here
#
# Don't forget to add your pipeline to the ITEM_PIPELINES setting
# See: https://doc.scrapy.org/en/latest/topics/item-pipeline.html


class BossproPipeline(object):
    f1,f2 = None,None
    def open_spider(self,spider):
        self.f1 = open('a.txt','w',encoding='utf-8')
        self.f2 = open('b.txt', 'w', encoding='utf-8')
    def process_item(self, item, spider):

        #item在同一時刻只可以接收到某一個指定item對象
        if item.__class__.__name__ == 'FirstItem':
            job_title = item['job_title']
            self.f1.write(job_title+'\n')
        else:
            job_desc = item['job_desc']
            self.f2.write(job_desc)
        return item

配置文件

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

# Scrapy settings for bossPro project
#
# For simplicity, this file contains only settings considered important or
# commonly used. You can find more settings consulting the documentation:
#
#     https://doc.scrapy.org/en/latest/topics/settings.html
#     https://doc.scrapy.org/en/latest/topics/downloader-middleware.html
#     https://doc.scrapy.org/en/latest/topics/spider-middleware.html

BOT_NAME = 'bossPro'

SPIDER_MODULES = ['bossPro.spiders']
NEWSPIDER_MODULE = 'bossPro.spiders'

USER_AGENT = 'Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/73.0.3683.86 Safari/537.36'

# Crawl responsibly by identifying yourself (and your website) on the user-agent
#USER_AGENT = 'bossPro (+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://doc.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://doc.scrapy.org/en/latest/topics/spider-middleware.html
#SPIDER_MIDDLEWARES = {
#    'bossPro.middlewares.BossproSpiderMiddleware': 543,
#}

# Enable or disable downloader middlewares
# See https://doc.scrapy.org/en/latest/topics/downloader-middleware.html
#DOWNLOADER_MIDDLEWARES = {
#    'bossPro.middlewares.BossproDownloaderMiddleware': 543,
#}

# Enable or disable extensions
# See https://doc.scrapy.org/en/latest/topics/extensions.html
#EXTENSIONS = {
#    'scrapy.extensions.telnet.TelnetConsole': None,
#}

# Configure item pipelines
# See https://doc.scrapy.org/en/latest/topics/item-pipeline.html
ITEM_PIPELINES = {
   'bossPro.pipelines.BossproPipeline': 300,
}

# Enable and configure the AutoThrottle extension (disabled by default)
# See https://doc.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://doc.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'