狗年开工毫无工作心情，胡思乱想后决定爬取豆瓣上的一下信息打发时间，毕竟之前基本没接触过爬虫，还是挺感兴趣的。

Scrapy简介

首先简单介绍一下Scrapy爬虫框架，主要是架构方面，这方面能快速理解scrapy是如何工作的。

Scrapy的数据流由执行引擎（Engine）控制，其基本过程如下：

1. 引擎从Spider中获取到初始Requests。
2. 引擎将该Requests放入调度器，并请求下一个要爬取的Requests。
3. 调度器返回下一个要爬取的Requests给引擎
4. 引擎将Requests通过下载器中间件转发给下载器(Downloader)。
5. 一旦页面下载完毕，下载器生成一个该页面的Response，并将其通过下载中间件(返回(response)方向)发送给引擎。
6. 引擎从下载器中接收到Response并通过Spider中间件(输入方向)发送给Spider处理。
7. Spider处理Response并返回爬取到的Item及(跟进的)新的Request给引擎。
8. 引擎将(Spider返回的)爬取到的Item交给ItemPipeline处理，将(Spider返回的)Request交给调度器，并请求下一个Requests（如果存在的话）。
9. (从第一步)重复直到调度器中没有更多地Request。

使用Scrapy创建的项目架构如下

其中：

1. spider 文件夹编写自己的爬虫；
2. settings.py 配置爬虫的默认信息，功能开关，中间件执行顺序等；
3. middlewares.py 中间件，主要是对功能的拓展，添加自定义功能，比如user-agent和proxy
4. item.py 定义抓取处理的字段
5. piplines.py 管道文件，处理item

爬取豆瓣小组

豆瓣小组的帖子主要核心内容是图片，因此要按不同的帖子分类下载。

settings.py

设置了user-agent，指定了中间件和piplines

BOT_NAME = 'douban'SPIDER_MODULES = ['douban.spiders']
NEWSPIDER_MODULE = 'douban.spiders'# Crawl responsibly by identifying yourself (and your website) on the user-agent
#USER_AGENT = 'douban (+http://www.yourdomain.com)'# Obey robots.txt rules
ROBOTSTXT_OBEY = FalseMY_USER_AGENT = ["Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; AcooBrowser; .NET CLR 1.1.4322; .NET CLR 2.0.50727)","Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0; Acoo Browser; SLCC1; .NET CLR 2.0.50727; Media Center PC 5.0; .NET CLR 3.0.04506)","Mozilla/4.0 (compatible; MSIE 7.0; AOL 9.5; AOLBuild 4337.35; Windows NT 5.1; .NET CLR 1.1.4322; .NET CLR 2.0.50727)","Mozilla/5.0 (Windows; U; MSIE 9.0; Windows NT 9.0; en-US)","Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Win64; x64; Trident/5.0; .NET CLR 3.5.30729; .NET CLR 3.0.30729; .NET CLR 2.0.50727; Media Center PC 6.0)","Mozilla/5.0 (compatible; MSIE 8.0; Windows NT 6.0; Trident/4.0; WOW64; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; .NET CLR 1.0.3705; .NET CLR 1.1.4322)","Mozilla/4.0 (compatible; MSIE 7.0b; Windows NT 5.2; .NET CLR 1.1.4322; .NET CLR 2.0.50727; InfoPath.2; .NET CLR 3.0.04506.30)","Mozilla/5.0 (Windows; U; Windows NT 5.1; zh-CN) AppleWebKit/523.15 (KHTML, like Gecko, Safari/419.3) Arora/0.3 (Change: 287 c9dfb30)","Mozilla/5.0 (X11; U; Linux; en-US) AppleWebKit/527+ (KHTML, like Gecko, Safari/419.3) Arora/0.6","Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.2pre) Gecko/20070215 K-Ninja/2.1.1","Mozilla/5.0 (Windows; U; Windows NT 5.1; zh-CN; rv:1.9) Gecko/20080705 Firefox/3.0 Kapiko/3.0","Mozilla/5.0 (X11; Linux i686; U;) Gecko/20070322 Kazehakase/0.4.5","Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.0.8) Gecko Fedora/1.9.0.8-1.fc10 Kazehakase/0.5.6","Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/535.11 (KHTML, like Gecko) Chrome/17.0.963.56 Safari/535.11","Mozilla/5.0 (Macintosh; Intel Mac OS X 10_7_3) AppleWebKit/535.20 (KHTML, like Gecko) Chrome/19.0.1036.7 Safari/535.20","Opera/9.80 (Macintosh; Intel Mac OS X 10.6.8; U; fr) Presto/2.9.168 Version/11.52","Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/536.11 (KHTML, like Gecko) Chrome/20.0.1132.11 TaoBrowser/2.0 Safari/536.11","Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/21.0.1180.71 Safari/537.1 LBBROWSER","Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; Trident/5.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0E; LBBROWSER)","Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; QQDownload 732; .NET4.0C; .NET4.0E; LBBROWSER)","Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/535.11 (KHTML, like Gecko) Chrome/17.0.963.84 Safari/535.11 LBBROWSER","Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.1; WOW64; Trident/5.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0E)","Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; Trident/5.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0E; QQBrowser/7.0.3698.400)","Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; QQDownload 732; .NET4.0C; .NET4.0E)","Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; Trident/4.0; SV1; QQDownload 732; .NET4.0C; .NET4.0E; 360SE)","Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; QQDownload 732; .NET4.0C; .NET4.0E)","Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.1; WOW64; Trident/5.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0E)","Mozilla/5.0 (Windows NT 5.1) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/21.0.1180.89 Safari/537.1","Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/21.0.1180.89 Safari/537.1","Mozilla/5.0 (iPad; U; CPU OS 4_2_1 like Mac OS X; zh-cn) AppleWebKit/533.17.9 (KHTML, like Gecko) Version/5.0.2 Mobile/8C148 Safari/6533.18.5","Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:2.0b13pre) Gecko/20110307 Firefox/4.0b13pre","Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:16.0) Gecko/20100101 Firefox/16.0","Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.11 (KHTML, like Gecko) Chrome/23.0.1271.64 Safari/537.11","Mozilla/5.0 (X11; U; Linux x86_64; zh-CN; rv:1.9.2.10) Gecko/20100922 Ubuntu/10.10 (maverick) Firefox/3.6.10","Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.36",]
DOWNLOADER_MIDDLEWARES = {'scrapy.downloadermiddleware.useragent.UserAgentMiddleware': None,'douban.middlewares.MyUserAgentMiddleware': 400,
}
COOKIES_ENABLES = True
DOWNLOAD_DELAY=1
ITEM_PIPELINES = {'douban.pipelines.DoubanPipeline': 1,
}

item.py

定义字段，包括作者，帖子名称，作者主页地址，图片地址

class DoubanItem(scrapy.Item):# define the fields for your item here like:# name = scrapy.Field()title=scrapy.Field()author=scrapy.Field()author_homepage=scrapy.Field()img_url=scrapy.Field()pass

middlewares.py

设置user-agent

class MyUserAgentMiddleware(UserAgentMiddleware):'''设置User-Agent'''def __init__(self, user_agent, ip):self.user_agent = user_agentself.ip=ip@classmethoddef from_crawler(cls, crawler):return cls(user_agent=crawler.settings.get('MY_USER_AGENT'), ip=crawler.settings.get('PROXIES'))def process_request(self, request, spider):agent = random.choice(self.user_agent)request.headers['User-Agent'] = agent

spiders/douban_spider.py

爬虫的处理代码，先登录然后爬取，如果有验证码，下载图片然后输入验证码

import urllibimport scrapy
from scrapy import Request, FormRequestfrom douban.items import DoubanItem
import jsonclass DoubanSpider(scrapy.Spider):name = 'douban'allowed_domains = ['douban.com']start_urls = []def start_requests(self):yield Request("https://www.douban.com/login", callback=self.parse, meta={"cookiejar":1})def parse(self, response):captcha = response.xpath('//img[@id="captcha_image"]/@src').extract()if len(captcha)>0:print("此时有验证码")localpath = "E:/spider/douban/captchar.jpg"urllib.request.urlretrieve(captcha[0],filename=localpath)print("请查看本地验证码图片并输入验证码")captcha_value=input()data = {"form_email": "*******@126.com","form_password": "*******","captcha-solution": str(captcha_value),"redir": "https://www.douban.com/group/haixiuzu/discussion?start=0"  # 登录后要返回的页面}else:print("此时没有验证码")data = {"form_email": "nofree1990@126.com","form_password": "8296926",# "redir": "https://www.douban.com/group/haixiuzu/discussion?start=0"  # 登录后要返回的页面}print("登陆中...")yield FormRequest.from_response(response,meta={"cookiejar": response.meta["cookiejar"]}, formdata=data, callback=self.parse_redirect)def parse_redirect(self, response):print("已登录豆瓣")title = response.xpath('//title//text()').extract()baseurl='https://www.douban.com/group/haixiuzu/discussion?start='for i in range(0, 625, 25):pageUrl=baseurl+str(i)yield Request(url=pageUrl, callback=self.parse_process,dont_filter = True)def parse_process(self, response):title = response.xpath('//title//text()').extract()items = response.xpath('//td//a/@href').extract()for item in items:if 'topic' in item:url=itemyield Request(url=item,callback=self.parse_img)def parse_img(self,response):img = DoubanItem()title=response.xpath('//title//text()').extract()img['title']=titleauthor=response.xpath('//div[@class="topic-doc"]//h3//a//text()').extract()img['author']=authorauthor_homepage = response.xpath('//div[@class="topic-doc"]//h3//a/@href').extract()img['author_homepage'] = author_homepageimg_url = response.xpath('//div[@class="image-wrapper"]//img/@src').extract()img['img_url'] = img_urlyield img

piplines.py

在此保存帖子信息，没有使用自带的保存图片的类主要原因是不够灵活。

class DoubanPipeline(object):def process_item(self, item, spider):author=item["author"][0]title=item["title"][0].replace('\n','').strip()author_homepage=item["author_homepage"][0]#路径dir="E:/spider/douban/img/"if not os.path.exists(dir):os.mkdir(dir)author_dir=dir+titleif not os.path.exists(author_dir):os.mkdir(author_dir)#用户信息txtinfo=open(author_dir+"/用户信息.txt", "w")info.write(author+'\n'+author_homepage)info.close()#保存图片count=1for url in item["img_url"]:path=author_dir+"/"+str(count)+".jpg"urllib.request.urlretrieve(url, filename=path)count += 1return item

爬虫结果

遇到的问题

主要问题就是爬取太频繁而被禁止，登录豆瓣也是想减少被禁止概率，但是发现没什么用。网上有很多解决方案，还是要伪造一些user-agent，使用proxy代理。也爬取过一些proxy存到数据库中，但是proxy比较慢，遂放弃。