web_crawler/middlewares.py

# 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
import random
# useful for handling different item types with a single interface

from spider.spiders.Redis_Con import Redis_Con



class SpiderSpiderMiddleware:
    # 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.
    cookie=''
    @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 SpiderDownloaderMiddleware:
    # 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.
    #f = Redis_Con()
   # cookie = f.getcookie()

    @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
        self.f=Redis_Con()
        print('开始 随机UA and 动态cookie')
        ua = random.choice(spider.settings.get('USER_AGENTS_LIST'))
        request.headers['User-Agent'] = ua
        request.headers['Referer'] = 'https://accounts.douban.com'
        request.headers['Host'] = 'movie.douban.com'
        self.cookie = self.f.getcookie()
        print("###借出cookie###\n"+self.cookie)
        now_c={}
        now_c['dbcl2']=self.cookie
        request.cookies = now_c
        #代理ip 由于使用免费代理延迟比较高,可能导致爬虫降速
        '''
        ip = self.f.getip()
        print('当前获取的代理ip'+str(ip))
        if ip != None:
            request.meta['proxy'] = ip
'''

        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
        print('###归还cookie###')
        print(self.cookie)
        self.f.reuturncookie(self.cookie)


        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
        # 如果遇到网络异常,也要归还cookie不然cookie丢失
        print('###出错!!!归还cookie###')
        print(self.cookie)
        self.f.reuturncookie(self.cookie)
        return None

    def spider_opened(self, spider):
        spider.logger.info('Spider opened: %s' % spider.name)


class IPDownloaderMiddleware:
    # 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.
    #f = Redis_Con()
   # cookie = f.getcookie()

    @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
        self.f=Redis_Con()
        print('获取免费代理IP中')
        ua = random.choice(spider.settings.get('USER_AGENTS_LIST'))
        request.headers['User-Agent'] = ua
        request.headers['Referer'] = 'www.baidu.com'
        request.headers['Host'] = 'www.kuaidaili.com'

        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
        return None

    def spider_opened(self, spider):
        spider.logger.info('Spider opened: %s' % spider.name)