python---Scrapy实现使用Splash进行网页信息爬取
一：回顾Scrapy的使用
二：爬取网址
（一）需求
最近想看漫画，奈何需要注册并支付...，想着爬取图片到本地进行浏览
（二）页面源码
我们可以知道图片网址存在一部分规则，我们可以按照这部分规则进行网站爬取。
但是我们可以知道在Img标签前面有<script>脚本信息，是用来对图片信息进行js渲染显示的，所以我们直接对该网页进行源码匹配是无法获取图片信息的。
这里我们就需要用到Splash技术
（三）Splash技术
https://www.jianshu.com/p/41e0a7e40824
三：代码实现
（一）主业务实现zymk.py
import scrapy from scrapy_splash import SplashRequest from zymkPro.items import ZymkproItem class ZymkSpider(scrapy.Spider): name = 'zymk' start_chapter = 700 allowed_domains = [] start_urls = ['http://www.zymk.cn/2/'] def start_requests(self): for url in self.start_urls: yield scrapy.Request(url=url, callback=self.parse, dont_filter=True) def parse(self,response): # 获取首页中所有的章节 Cp_a = response.xpath('//ul[@id="chapterList"]/li') #解析实体 for cp in Cp_a: cp_url = cp.xpath("./a/@href").extract_first() #获取链接 cp_title = cp.xpath("./a/text()").extract_first() #获取文本 try: if int(cp_title.split("话")[0]) < self.start_chapter: continue except ValueError: print("异常番号") continue if not cp_url.startswith("http"): cp_url = "https://www.zymk.cn/2/%s" % cp_url yield SplashRequest(url=cp_url,callback=self.parseNextClsPage, #对于这里URL，我们是要去获取图片网址，而这里是js动态渲染的，所以需要是要Splash技术 args={'timeout': 3600,'wait':1}) def parseNextClsPage(self,response): # 下面是所有章节去查找所有的图片 xh_img = response.xpath('//img[@class="comicimg"]') xh_img_samp = xh_img.xpath("./@src").extract_first() ch_name = response.xpath('//div[@id="readEnd"]/div/p/strong/text()').extract_first() href_list = xh_img_samp.split(".jpg") xh_img_href_list = [] xh_pages = response.xpath("//select[@class='selectpage']") xh_pagesC = xh_pages.xpath("./option[1]/text()").extract_first() xh_pagesCount = int(xh_pagesC.split("/")[1][:-1]) xh_href_form = (href_list[0][:-1]).split("//")[1] #新操作 xh_href_form_l = xh_href_form.split("/") xh_href_form_l[0] = "mhpic.xiaomingtaiji.net" xh_href_form = "/".join(xh_href_form_l) xh_href_latt = href_list[1] for i in range(1,xh_pagesCount+1): new_img_href= "http://"+xh_href_form+("%d.jpg"%i)+xh_href_latt #获取所有图片信息 item_obj = ZymkproItem(title=ch_name, img_url=new_img_href,img_number=i) yield item_obj
（二）item.py设置字段
# Define here the models for your scraped items # # See documentation in: # https://docs.scrapy.org/en/latest/topics/items.html import scrapy class ZymkproItem(scrapy.Item): # define the fields for your item here like: title = scrapy.Field() img_url = scrapy.Field() img_number = scrapy.Field()
（三）中间件middlewares.py实现动态UA
# Define here the models for your spider middleware # # See documentation in: # https://docs.scrapy.org/en/latest/topics/spider-middleware.html from scrapy import signals # useful for handling different item types with a single interface from itemadapter import is_item, ItemAdapter from fake_useragent import UserAgent class ZymkproSpiderMiddleware: # Not all methods need to be defined. If a method is not defined, # scrapy acts as if the spider middleware does not modify the # passed objects. @classmethod def from_crawler(cls, crawler): # This method is used by Scrapy to create your spiders. s = cls() crawler.signals.connect(s.spider_opened, signal=signals.spider_opened) return s def process_spider_input(self, response, spider): # Called for each response that goes through the spider # middleware and into the spider. # Should return None or raise an exception. return None def process_spider_output(self, response, result, spider): # Called with the results returned from the Spider, after # it has processed the response. # Must return an iterable of Request, or item objects. for i in result: yield i def process_spider_exception(self, response, exception, spider): # Called when a spider or process_spider_input() method # (from other spider middleware) raises an exception. # Should return either None or an iterable of Request or item objects. pass def process_start_requests(self, start_requests, spider): # Called with the start requests of the spider, and works # similarly to the process_spider_output() method, except # that it doesn’t have a response associated. # Must return only requests (not items). for r in start_requests: yield r def spider_opened(self, spider): spider.logger.info('Spider opened: %s' % spider.name) class ZymkproDownloaderMiddleware: # Not all methods need to be defined. If a method is not defined, # scrapy acts as if the downloader middleware does not modify the # passed objects. @classmethod def from_crawler(cls, crawler): # This method is used by Scrapy to create your spiders. s = cls() crawler.signals.connect(s.spider_opened, signal=signals.spider_opened) return s def process_request(self, request, spider): # Called for each request that goes through the downloader # middleware. # Must either: # - return None: continue processing this request # - or return a Response object # - or return a Request object # - or raise IgnoreRequest: process_exception() methods of # installed downloader middleware will be called return None def process_response(self, request, response, spider): # Called with the response returned from the downloader. # Must either; # - return a Response object # - return a Request object # - or raise IgnoreRequest return response def process_exception(self, request, exception, spider): # Called when a download handler or a process_request() # (from other downloader middleware) raises an exception. # Must either: # - return None: continue processing this exception # - return a Response object: stops process_exception() chain # - return a Request object: stops process_exception() chain pass def spider_opened(self, spider): spider.logger.info('Spider opened: %s' % spider.name) class MyUseragent(object): def __init__(self): self.ua = UserAgent() def process_request(self,request,spider): referer=request.url if referer: request.headers["referer"] = referer request.headers.setdefault("User-Agent", self.ua.random)
（四）持久化操作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 ItemAdapter import requests,os from fake_useragent import UserAgent class ZymkproPipeline: def process_item(self, item, spider): file_path = os.path.join(os.path.dirname(os.path.abspath(__file__)), 'upload', item['title']) ua = UserAgent().random if not os.path.isdir(file_path): os.makedirs(file_path) header = { 'User-Agent': ua, 'Referer': item['img_url'] } response = requests.get(item['img_url'], stream=False,headers=header) with open(os.path.join(file_path,"%d.jpg"%item['img_number']), "wb") as fp: fp.write(response.content) return item
（五）配置文件setting.py
# Scrapy settings for zymkPro 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.html BOT_NAME = 'zymkPro' SPIDER_MODULES = ['zymkPro.spiders'] NEWSPIDER_MODULE = 'zymkPro.spiders' # Crawl responsibly by identifying yourself (and your website) on the user-agent #USER_AGENT = 'zymkPro (+http://www.yourdomain.com)' # Obey robots.txt rules ROBOTSTXT_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 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': 'zh-CN,zh;q=0.9', 'USER_AGENT': "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.149 Safari/537.36", } # Enable or disable spider middlewares # See https://docs.scrapy.org/en/latest/topics/spider-middleware.html #SPIDER_MIDDLEWARES = { # 'zymkPro.middlewares.ZymkproSpiderMiddleware': 543, #} # Enable or disable downloader middlewares # See https://docs.scrapy.org/en/latest/topics/downloader-middleware.html DOWNLOADER_MIDDLEWARES = { 'zymkPro.middlewares.ZymkproDownloaderMiddleware': 543, 'zymkPro.middlewares.MyUseragent': 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 = { 'zymkPro.pipelines.ZymkproPipeline': 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' SPLASH_URL = 'http://192.168.58.139:8050' DOWNLOADER_MIDDLEWARES = { 'scrapy_splash.SplashCookiesMiddleware': 723, 'scrapy_splash.SplashMiddleware': 725, 'scrapy.downloadermiddlewares.httpcompression.HttpCompressionMiddleware': 810, } SPIDER_MIDDLEWARES = { 'scrapy_splash.SplashDeduplicateArgsMiddleware': 100, } DUPEFILTER_CLASS = 'scrapy_splash.SplashAwareDupeFilter' HTTPCACHE_STORAGE = 'scrapy_splash.SplashAwareFSCacheStorage'
四：结果显示
五：项目链接
https://github.com/viewmountain/Scrapy-Instance
六：疑惑---图片防盗链如果处理？？太久了，忘了
这里出现的情况是，我们直接通过scrapy获取的图片网址和实际的网址有所出入，所以我们在上面修改了前面的域名，才成功的。是因为进行了反爬操作？？
动态修改了我们获取的图片链接？？
