Scrapy框架
Scrapy
Scrapy是一个为了爬取网站数据，提取结构性数据而编写的应用框架。 其可以应用在数据挖掘，信息处理或存储历史数据等一系列的程序中。
其最初是为了页面抓取 (更确切来说, 网络抓取 )所设计的， 也可以应用在获取API所返回的数据(例如 Amazon Associates Web Services ) 或者通用的网络爬虫。Scrapy用途广泛，可以用于数据挖掘、监测和自动化测试。
Scrapy 使用了 Twisted异步网络库来处理网络通讯。整体架构大致如下
Scrapy主要包括了以下组件：
- 引擎(Scrapy)
用来处理整个系统的数据流处理, 触发事务(框架核心) - 调度器(Scheduler)
用来接受引擎发过来的请求, 压入队列中, 并在引擎再次请求的时候返回. 可以想像成一个URL（抓取网页的网址或者说是链接）的优先队列, 由它来决定下一个要抓取的网址是什么, 同时去除重复的网址 - 下载器(Downloader)
用于下载网页内容, 并将网页内容返回给蜘蛛(Scrapy下载器是建立在twisted这个高效的异步模型上的) - 爬虫(Spiders)
爬虫是主要干活的, 用于从特定的网页中提取自己需要的信息, 即所谓的实体(Item)。用户也可以从中提取出链接,让Scrapy继续抓取下一个页面 - 项目管道(Pipeline)
负责处理爬虫从网页中抽取的实体，主要的功能是持久化实体、验证实体的有效性、清除不需要的信息。当页面被爬虫解析后，将被发送到项目管道，并经过几个特定的次序处理数据。 - 下载器中间件(Downloader Middlewares)
位于Scrapy引擎和下载器之间的框架，主要是处理Scrapy引擎与下载器之间的请求及响应。 - 爬虫中间件(Spider Middlewares)
介于Scrapy引擎和爬虫之间的框架，主要工作是处理蜘蛛的响应输入和请求输出。 - 调度中间件(Scheduler Middewares)
介于Scrapy引擎和调度之间的中间件，从Scrapy引擎发送到调度的请求和响应。
Scrapy运行流程大概如下：
- 引擎从调度器中取出一个链接(URL)用于接下来的抓取
- 引擎把URL封装成一个请求(Request)传给下载器
- 下载器把资源下载下来，并封装成应答包(Response)
- 爬虫解析Response
- 解析出实体（Item）,则交给实体管道进行进一步的处理
- 解析出的是链接（URL）,则把URL交给调度器等待抓取
一、安装
Linux: pip3 install scrapy Windows: pip3 install wheel D:twisted.wheel pip3 install D:twisted.wheel pip3 install scrapy 报错：twisted安装错误 pywin32 PS: - python3对twisted未完全支持 - python2 对Scrapy支持更好些 import scrapy
二、基本使用
1. 基本命令
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Django: django-admin startproject mysite cd mysite python manage.py startapp app01 Scrapy： # 创建项目，在当前目录中创建中创建一个项目文件（类似于Django） scrapy startproject sp1 生成目录如下： sp1 - sp1 - spiders 目录，放置创建的爬虫应用 - middlewares.py 中间件 - items.py 格式化，与pipelines.py一同做持久化 - pipelines.py 持久化 - settings.py 配置文件 - scrapy.cfg 配置 # 创建爬虫应用 cd sp1 scrapy genspider xiaohuar xiaohuar.com # 创建了xiaohuar.py scrapy genspider baidu baidu.com # 创建了baidu.py # 展示爬虫应用列表 scrapy list # 执行爬虫，进入project scrapy crawl baidu scrapy crawl baidu --nolog |
文件说明：
- scrapy.cfg 项目的主配置信息。（真正爬虫相关的配置信息在settings.py文件中）
- items.py 设置数据存储模板，用于结构化数据，如：Django的Model
- pipelines 数据处理行为，如：一般结构化的数据持久化
- settings.py 配置文件，如：递归的层数、并发数，延迟下载等
- spiders 爬虫目录，如：创建文件，编写爬虫规则
注意：一般创建爬虫文件时，以网站域名命名
2. 基本操作
2.1 selector作筛选
hxs = Selector(response=response) # print(hxs) user_list = hxs.xpath('//div[@class="item masonry_brick"]') for item in user_list: price = item.xpath('./span[@class="price"]/text()').extract_first() url = item.xpath('div[@class="item_t"]/div[@class="class"]//a/@href').extract_first() print(price,url) result = hxs.xpath('/a[re:test(@href,"http://www.xiaohuar.com/list-1-\d+.html")]/@href') print(result) result = ['http://www.xiaohuar.com/list-1-1.html','http://www.xiaohuar.com/list-1-2.html']
2.2 yield Request(url=url,callback=self.parse) # 迭代去执行
2.3 代码的实现
# -*- coding: utf-8 -*- import scrapy class BaiduSpider(scrapy.Spider): name = 'baidu' # 爬虫应用的名称，通过此名称启动爬虫命令 allowed_domains = ['baidu.com'] # 允许的域名 start_urls = ['http://baidu.com/'] # 起始URL def parse(self, response): print(response.text) print(response.body)
import scrapy from scrapy.selector import HtmlXPathSelector,Selector from scrapy.http import Request class XiaohuarSpider(scrapy.Spider): name = 'xiaohuar' allowed_domains = ['xiaohuar.com'] start_urls = ['http://www.xiaohuar.com/hua/'] # 起始url def parse(self, response): # 要废弃 # hxs = HtmlXPathSelector(response) # 拿到的内容response转换成对象 # print(hxs) # result = hxs.select('//a[@class="item_list"]') # select：表示查找；//a :是找页面所有的a标签 ## result = hxs.select('//a[@class="item_list"]').extract() # .extract()使返回的值result不是对象，而是列表[<a></a>,<a></a>...] ## result = hxs.select('//a[@class="item_list"]').extract_one() # 拿第一个 ## result = hxs.select('//a[@class="item_list"]/@href').extract_one() # 表示拿href属性 ## result = hxs.select('//a[@class="item_list"]/text()').extract_one() # 表示拿文本内容 ############################# 以上写法不推荐 ############################# ############################### 推荐以下方式 ############################## hxs = Selector(response=response) # print(hxs) user_list = hxs.xpath('//div[@class="item masonry_brick"]') # 拿到的是对象，但可以对这个对象进行循环。找到class="item masonry_brick"的所有div标签 for item in user_list: # 每个item也是对象 price = item.xpath('.//span[@class="price"]/text()').extract_first() # 相对于当前标签的找子子孙孙使用.//span... # price = item.xpath('//span[@class="price"]/text()').extract_first()是错误的,因为//span...是向整个html里找 url = item.xpath('div[@class="item_t"]/div[@class="class"]//a/@href').extract_first() # / 表示去儿子里找，//表示到子子孙孙里找。但必须是在内部才有意义。最外层//和/ 都是有特殊意义 print(price,url) # 上面找的只是第一页索引的内容，下面找的是分页的内容 result = hxs.xpath('/a[re:test(@href,"http://www.xiaohuar.com/list-1-\d+.html")]/@href') # re:test(） 正则查找 print(result) result = ['http://www.xiaohuar.com/list-1-1.html','http://www.xiaohuar.com/list-1-2.html'] # 规则 for url in result: yield Request(url=url,callback=self.parse) # yield Request(url=url) 只是把url封装起来放到调度器里了，callback=self.parse源源不断的发请求，迭代去执行
补充：
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选择器： // # 子子孙孙 / # 儿子 /@属性名 # 取属性 /text() # 取文本 特殊： item.xpath('./') # 相对当前子孙中找 item.xpath('a') # 相对当前儿子中找 |
三、深入了解
（一）以下内容 以登录抽屉并点赞来举例进行深入了解
1. 起始URL
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不指明callback=self.parse1情况下，默认下载完后执行 parse函数import scrapyfrom scrapy.http import Requestclass ChoutiSpider(scrapy.Spider): name = 'chouti' allowed_domains = ['chouti.com'] start_urls = ['http://chouti.com/'] def start_requests(self): # 看源码，如果我们没有start_requests函数，默认会执行继承的类scrapy.Spider里的start_requests方法 for url in self.start_urls: yield Request(url, dont_filter=True,callback=self.parse1) # dont_filter=True对爬取的url不去重 def parse1(self, response): pass |
2. 如何发POST请求，携带请求头，cookie，数据
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requests.get(params={},headers={},cookies={})requests.post(params={},headers={},cookies={},data={},json={}) |
2.1 requests请求相关的参数
url, method='GET', headers=None, body=None, cookies=None, ...
2.2 GET请求
url, method='GET', headers={}, cookies={}, cookiejar # cookies可以是字典也可以是cookiejar对象
2.3 POST请求
url, method='GET', headers={}, cookies={}, cookiejar # cookies可以是字典也可以是cookiejar对象 body=None, # 请求体 请求头application/x-www-form-urlencoded; charset=UTF-8格式下，数据"phone=86155fa&password=asdf&oneMonth=1" 请求头json格式application/json; charset=UTF-8，数据时字典格式"{k1:'v1','k2':'v2'}" 当请求头application/x-www-form-urlencoded; charset=UTF-8格式下，form_data = {'user':'xyp','pwd': 123}需要for循环拼接成"user=xyp$pwd=123" 但scrapy框架提供了模块可以自动完成拼接 import urllib.parse data = urllib.parse.urlencode({'k1':'v1','k2':'v2'}) print(data) # ---> "k1=v1&k2=v2" 请求头json格式application/json; charset=UTF-8格式下 json.dumsp({k1:'v1','k2':'v2'}) "{k1:'v1','k2':'v2'}"
2.4 POST请求示例
Request( url='http://dig.chouti.com/login', method='POST', headers={'Content-Type': 'application/x-www-form-urlencoded; charset=UTF-8'}, body='phone=8615131255089&password=pppppppp&oneMonth=1', callback=self.check_login )
2.5 cookie
Request( url='http://dig.chouti.com/login', method='POST', headers={'Content-Type': 'application/x-www-form-urlencoded; charset=UTF-8'}, body='phone=8615131255089&password=pppppppp&oneMonth=1', cookies=self.cookie_dict, callback=self.check_login )
具体代码实现：
#以下代码是循环不停的，加上去重操作 # -*- coding: utf-8 -*- import scrapy from scrapy.http import Request from scrapy.selector import Selector class ChoutiSpider(scrapy.Spider): name = 'chouti' allowed_domains = ['chouti.com'] start_urls = ['http://chouti.com/'] cookie_dict = {} """ 1. 发送一个GET请求,抽屉 获取cookie 2. 用户密码POST登录：携带上一次cookie 返回值：9999表示登录成功 3. 为所欲为，携带cookie，点赞 """ def start_requests(self): # 看源码，如果我们没有start_requests函数，默认会执行继承的类scrapy.Spider里的start_requests方法 for url in self.start_urls: yield Request(url, dont_filter=True,callback=self.parse1) # dont_filter=True对爬取的url不去重 def parse1(self,response): # response.text 首页所有内容 from scrapy.http.cookies import CookieJar cookie_jar = CookieJar() # 对象，对象中封装了 cookies cookie_jar.extract_cookies(response, response.request) # 去响应中获取cookies for k, v in cookie_jar._cookies.items(): for i, j in v.items(): for m, n in j.items(): self.cookie_dict[m] = n.value post_dict = { 'phone': '8615131255089', 'password': 'woshiniba', 'oneMonth': 1, } import urllib.parse # 目的：发送POST进行登录 yield Request( url="http://dig.chouti.com/login", method='POST', cookies=self.cookie_dict, # 或者cookies=self.cookie_jar 也行 body=urllib.parse.urlencode(post_dict), # 要发送的body数据 headers={'Content-Type':'application/x-www-form-urlencoded; charset=UTF-8'}, callback=self.parse2 # 回调函数 ) def parse2(self,response): print(response.text) # 这里需根据response判断是否登录成功，此处省略判断 # 获取新闻列表 yield Request(url='http://dig.chouti.com/',cookies=self.cookie_dict,callback=self.parse3) def parse3(self,response): # 找div，class=part2, 获取share-linkid属性，得到文章id hxs = Selector(response) link_id_list = hxs.xpath('//div[@class="part2"]/@share-linkid').extract() # 取到当前页面所有的文章id print(link_id_list) for link_id in link_id_list: # 获取每一个ID去点赞 base_url = "http://dig.chouti.com/link/vote?linksId=%s" %(link_id,) yield Request(url=base_url,method="POST",cookies=self.cookie_dict,callback=self.parse4) #################### 以上只是把首页文章全部点赞 #################### ####################### 分页每个文章都点赞 ####################### page_list = hxs.xpath('//div[@id="dig_lcpage"]//a/@href').extract() # 拿到所有的页码 for page in page_list: #page ： /all/hot/recent/2 page_url = "http://dig.chouti.com%s" %(page,) yield Request(url=page_url,method='GET',callback=self.parse3) # 循环不同页码点赞 def parse4(self, response): print(response.text)
（二）以下内容 以获取煎蛋文章标题和url来举例进行持久化的了解
3. 持久化
3.1 获取煎蛋文章标题和url：具体代码及持久化详细注释
# -*- coding: utf-8 -*- import scrapy from scrapy.http import Request from scrapy.selector import Selector class JianDanSpider(scrapy.Spider): name = 'jiandan' allowed_domains = ['jandan.net'] start_urls = ['http://jandan.net/'] def start_requests(self): for url in self.start_urls: yield Request(url, dont_filter=True,callback=self.parse1) def parse1(self,response): # response.text 首页所有内容 hxs = Selector(response) a_list = hxs.xpath('//div[@class="indexs"]/h2') for tag in a_list: url = tag.xpath('./a/@href').extract_first() text = tag.xpath('./a/text()').extract_first() from ..items import Sp2Item yield Sp2Item(url=url,text=text) # 创建特殊的对象直接交给pipeline，没有做持久化操作，只是把工作转交给了pipeline #以上获取的是首页文章的文本和url # 获取页码 [url,url] """ for url in url_list: yield Request(url=url,callback=self.parse1) """
import scrapy class Sp2Item(scrapy.Item): # define the fields for your item here like: # name = scrapy.Field() url = scrapy.Field() text = scrapy.Field()
# -*- coding: utf-8 -*- # Define your item pipelines here # # Don't forget to add your pipeline to the ITEM_PIPELINES setting # See: http://doc.scrapy.org/en/latest/topics/item-pipeline.html class Sp2Pipeline(object): def __init__(self): self.f = None def process_item(self, item, spider): """ :param item: 爬虫中yield回来的对象 :param spider: 爬虫对象 obj = JianDanSpider() :return: """ if spider.name == 'jiadnan': pass print(item) self.f.write('....') # 将item传递给下一个pipeline的process_item方法 # return item # from scrapy.exceptions import DropItem # raise DropItem() 下一个pipeline的process_item方法不在执行 @classmethod def from_crawler(cls, crawler): """ 初始化时候，用于创建pipeline对象 :param crawler: :return: """ # val = crawler.settings.get('MMMM') print('执行pipeline的from_crawler，进行实例化对象') return cls() def open_spider(self,spider): """ 爬虫开始执行时，调用 :param spider: :return: """ print('打开爬虫') self.f = open('a.log','a+') def close_spider(self,spider): """ 爬虫关闭时，被调用 :param spider: :return: """ self.f.close()
ITEM_PIPELINES = { 'sp2.pipelines.Sp2Pipeline': 300, # 300是优先级 }
3.2 总结
① pipeline执行的前提
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- spider中yield Item对象- settings中注册 ITEM_PIPELINES = { 'sp2.pipelines.Sp2Pipeline': 300, # 300为优先级，越小越先执行 'sp2.pipelines.Sp3Pipeline': 100, } |
② 编写pipeline
class Sp2Pipeline(object): def __init__(self): self.f = None def process_item(self, item, spider): """ :param item: 爬虫中yield回来的对象 :param spider: 爬虫对象 obj = JianDanSpider() :return: """ print(item) self.f.write('....') return item # from scrapy.exceptions import DropItem # raise DropItem() 下一个pipeline的process_item方法不在执行 @classmethod def from_crawler(cls, crawler): """ 初始化时候，用于创建pipeline对象 :param crawler: :return: """ # val = crawler.settings.get('MMMM') print('执行pipeline的from_crawler，进行实例化对象') return cls() def open_spider(self,spider): """ 爬虫开始执行时，调用 :param spider: :return: """ print('打开爬虫') self.f = open('a.log','a+') def close_spider(self,spider): """ 爬虫关闭时，被调用 :param spider: :return: """ self.f.close()
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当注册Sp2Pipeline和Sp3Pipeline时，先执行优先级高的__init__函数初始化方法，from_crawler方法，open_spider方法。但是不继续执行优先级高的爬虫方法。而是等优先级低的执行完__init__函数初始化方法，from_crawler方法，open_spider方法后才会执行爬虫方法。PipeLine是全局生效，所有爬虫都会执行，个别做特殊操作： 通过spider.name判断 |
③ pipelines.py可以自定义的方法，及程序运行顺序
# class CustomPipeline(object): # def __init__(self,val): # self.val = val # # def process_item(self, item, spider): # # 操作并进行持久化 # # # return表示会被后续的pipeline继续处理 # return item # # # 表示将item丢弃，不会被后续pipeline处理 # # raise DropItem() # # @classmethod # def from_crawler(cls, crawler): # """ # 初始化时候，用于创建pipeline对象 # :param crawler: # :return: # """ # val = crawler.settings.get('MMMM') # return cls(val) # # def open_spider(self,spider): # """ # 爬虫开始执行时，调用 # :param spider: # :return: # """ # print('000000') # # def close_spider(self,spider): # """ # 爬虫关闭时，被调用 # :param spider: # :return: # """ # print('111111') """ 检测 CustomPipeline类中是否有 from_crawler方法 如果有： obj = 类.from_crawler() 如果没有： obj = 类() obj.open_spider() while True: 爬虫运行，并且执行parse各种各样的爬虫方法，yield item obj.process_item() obj.close_spider() """
以上以例子为了解的内容结束。
4. 自定义去重规则
4.1 配置文件中指定
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scrapy默认使用 scrapy.dupefilter.RFPDupeFilter 进行去重，默认在settings相关配置有： DUPEFILTER_CLASS = 'scrapy.dupefilter.RFPDupeFilter' DUPEFILTER_DEBUG = False JOBDIR = "保存范文记录的日志路径，如：/root/" # 最终路径为 /root/requests.seen |
4.2 自定义URL去重操作
class RepeatUrl: def __init__(self): self.visited_url = set() # 放在当前服务的内存 @classmethod def from_settings(cls, settings): """ 初始化时，调用 :param settings: :return: """ return cls() def request_seen(self, request): """ 检测当前请求是否已经被访问过 :param request: :return: True表示已经访问过；False表示未访问过 """ if request.url in self.visited_url: return True self.visited_url.add(request.url) return False def open(self): """ 开始爬去请求时，调用 :return: """ print('open replication') def close(self, reason): """ 结束爬虫爬取时，调用 :param reason: :return: """ print('close replication') def log(self, request, spider): """ 记录日志 :param request: :param spider: :return: """ print('repeat', request.url)
DUPEFILTER_CLASS = 'sp2.rep.RepeatUrl'
5. 自定义扩展【基于信号】
from scrapy import signals class MyExtension(object): def __init__(self, value): self.value = value @classmethod def from_crawler(cls, crawler): val = crawler.settings.getint('MMMM') ext = cls(val) # 在scrapy中注册信号： spider_opened crawler.signals.connect(ext.opened, signal=signals.spider_opened) # ext.opened触发信号时执行的函数 # 在scrapy中注册信号： spider_closed crawler.signals.connect(ext.closed, signal=signals.spider_closed) return ext def opened(self, spider): print('open') def closed(self, spider): print('close')
EXTENSIONS = { # 'scrapy.extensions.telnet.TelnetConsole': None, }
6. 中间件
6.1 爬虫中间件
SPIDER_MIDDLEWARES = { 'sp3.middlewares.Sp3SpiderMiddleware': 543, }
class Sp3SpiderMiddleware(object): def process_spider_input(self,response, spider): """ 下载完成，执行，然后交给parse处理 :param response: :param spider: :return: """ pass def process_spider_output(self,response, result, spider): """ spider处理完成，返回时调用 :param response: :param result: :param spider: :return: 必须返回包含 Request 或 Item 对象的可迭代对象(iterable) """ return result def process_spider_exception(self,response, exception, spider): """ 异常调用 :param response: :param exception: :param spider: :return: None,继续交给后续中间件处理异常；含 Response 或 Item 的可迭代对象(iterable)，交给调度器或pipeline """ return None def process_start_requests(self,start_requests, spider): """ 爬虫启动时调用 :param start_requests: :param spider: :return: 包含 Request 对象的可迭代对象 """ return start_requests
6.2 下载中间件
DOWNLOADER_MIDDLEWARES = { 'sp3.middlewares.DownMiddleware1': 543, }
class DownMiddleware1(object): def process_request(self, request, spider): """ 请求需要被下载时，经过所有下载器中间件的process_request调用 :param request: :param spider: :return: None,继续后续中间件去下载； Response对象，停止process_request的执行，开始执行process_response Request对象，停止中间件的执行，将Request重新调度器 raise IgnoreRequest异常，停止process_request的执行，开始执行process_exception """ """ from scrapy.http import Request # print(request) # request.method = "POST" request.headers['proxy'] = "{'ip_port': '111.11.228.75:80', 'user_pass': ''}," return None """ """ from scrapy.http import Response import requests v = request.get('http://www.baidu.com') data = Response(url='xxxxxxxx',body=v.content,request=request) return data """ pass def process_response(self, request, response, spider): """ spider处理完成，返回时调用 :param response: :param result: :param spider: :return: Response 对象：转交给其他中间件process_response Request 对象：停止中间件，request会被重新调度下载 raise IgnoreRequest 异常：调用Request.errback """ print('response1') return response def process_exception(self, request, exception, spider): """ 当下载处理器(download handler)或 process_request() (下载中间件)抛出异常 :param response: :param exception: :param spider: :return: None：继续交给后续中间件处理异常； Response对象：停止后续process_exception方法 Request对象：停止中间件，request将会被重新调用下载 """ return None
7. 自定义命令【scrapy crawl baidu看源码的入口】
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在spiders同级创建任意目录，如：commands在其中创建 crawlall.py 文件 （此处文件名就是自定义的命令） |
class Command(ScrapyCommand): requires_project = True def syntax(self): return '[options]' def short_desc(self): return 'Runs all of the spiders' def run(self, args, opts): # 爬虫列表 spider_list = self.crawler_process.spiders.list() for name in spider_list: print(name) # # # 初始化爬虫 self.crawler_process.crawl(name, **opts.__dict__) # 开始执行所有的爬虫 self.crawler_process.start()
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在settings.py 中添加配置 COMMANDS_MODULE = '项目名称.目录名称'在项目目录执行命令：scrapy crawlall 就多了命令：scrapy crawlall scrapy crawlall --nolog #---> xxxscrapy genspider ooo ooo.comscrapy crawlall --nolog ''' ---> xxx ooo''' |
8. 其他（scrapy配置文件）
# -*- coding: utf-8 -*- # Scrapy settings for step8_king project # # For simplicity, this file contains only settings considered important or # commonly used. You can find more settings consulting the documentation: # # http://doc.scrapy.org/en/latest/topics/settings.html # http://scrapy.readthedocs.org/en/latest/topics/downloader-middleware.html # http://scrapy.readthedocs.org/en/latest/topics/spider-middleware.html # 1. 爬虫名称 BOT_NAME = 'step8_king' # 2. 爬虫应用路径 SPIDER_MODULES = ['step8_king.spiders'] NEWSPIDER_MODULE = 'step8_king.spiders' # Crawl responsibly by identifying yourself (and your website) on the user-agent # 3. 客户端 user-agent请求头 # USER_AGENT = 'step8_king (+http://www.yourdomain.com)' # user-agent客户端设备 # Obey robots.txt rules # 4. 禁止爬虫配置 # ROBOTSTXT_OBEY = False # 是否遵循爬虫协议 # Configure maximum concurrent requests performed by Scrapy (default: 16) # 5. 并发请求数 # CONCURRENT_REQUESTS = 4 # Configure a delay for requests for the same website (default: 0) # See http://scrapy.readthedocs.org/en/latest/topics/settings.html#download-delay # See also autothrottle settings and docs # 6. 延迟下载秒数 # DOWNLOAD_DELAY = 2 # The download delay setting will honor only one of: # 如果设置单域名访问并发数和单IP访问并发数会把第五条并发请求数覆盖 # 7. 单域名访问并发数，并且延迟下次秒数也应用在每个域名 # CONCURRENT_REQUESTS_PER_DOMAIN = 2 # 单IP访问并发数，如果有值则忽略：CONCURRENT_REQUESTS_PER_DOMAIN，并且延迟下次秒数也应用在每个IP # CONCURRENT_REQUESTS_PER_IP = 3 # Disable cookies (enabled by default) # 8. 是否支持cookie，cookiejar进行操作cookie # COOKIES_ENABLED = True # COOKIES_DEBUG = True # Disable Telnet Console (enabled by default) # 9. Telnet用于查看当前爬虫的信息，操作爬虫等... # 对于你的爬虫进行监控 # 使用telnet ip port ，然后通过命令操作 # TELNETCONSOLE_ENABLED = True # TELNETCONSOLE_HOST = '127.0.0.1' # TELNETCONSOLE_PORT = [6023,] # 10. 默认请求头，设置所有的请求头，但是优先级比较低，在爬虫名.py文件中设置请求头优先级高一些 # 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', # } # Configure item pipelines # See http://scrapy.readthedocs.org/en/latest/topics/item-pipeline.html # 11. 定义pipeline处理请求 # ITEM_PIPELINES = { # 'step8_king.pipelines.JsonPipeline': 700, # 'step8_king.pipelines.FilePipeline': 500, # } # 12. 自定义扩展，基于信号进行调用 # Enable or disable extensions # See http://scrapy.readthedocs.org/en/latest/topics/extensions.html # EXTENSIONS = { # # 'step8_king.extensions.MyExtension': 500, # } # 13. 爬虫允许的最大深度，可以通过meta查看当前深度；0表示无深度 # DEPTH_LIMIT = 3 # 14. 爬取时，0表示深度优先Lifo(默认)；1表示广度优先FiFo # 后进先出，深度优先 # DEPTH_PRIORITY = 0 # SCHEDULER_DISK_QUEUE = 'scrapy.squeue.PickleLifoDiskQueue' # SCHEDULER_MEMORY_QUEUE = 'scrapy.squeue.LifoMemoryQueue' # 先进先出，广度优先 # DEPTH_PRIORITY = 1 # SCHEDULER_DISK_QUEUE = 'scrapy.squeue.PickleFifoDiskQueue' # SCHEDULER_MEMORY_QUEUE = 'scrapy.squeue.FifoMemoryQueue' # 15. 调度器队列 # SCHEDULER = 'scrapy.core.scheduler.Scheduler' # scrapy框架默认的调度器，与14条队列结合 # from scrapy.core.scheduler import Scheduler # 16. 访问URL去重 # DUPEFILTER_CLASS = 'step8_king.duplication.RepeatUrl' # Enable and configure the AutoThrottle extension (disabled by default) # See http://doc.scrapy.org/en/latest/topics/autothrottle.html """ 17. 自动限速算法 from scrapy.contrib.throttle import AutoThrottle 自动限速设置 1. 获取最小延迟 DOWNLOAD_DELAY 2. 获取最大延迟 AUTOTHROTTLE_MAX_DELAY 3. 设置初始下载延迟 AUTOTHROTTLE_START_DELAY 4. 当请求下载完成后，获取其"连接"时间 latency，即：请求连接到接受到响应头之间的时间 5. 用于计算的... AUTOTHROTTLE_TARGET_CONCURRENCY target_delay = latency / self.target_concurrency new_delay = (slot.delay + target_delay) / 2.0 # 表示上一次的延迟时间 new_delay = max(target_delay, new_delay) new_delay = min(max(self.mindelay, new_delay), self.maxdelay) slot.delay = new_delay """ # 开始自动限速 # AUTOTHROTTLE_ENABLED = True # The initial download delay # 初始下载延迟 # AUTOTHROTTLE_START_DELAY = 5 # The maximum download delay to be set in case of high latencies # 最大下载延迟 # AUTOTHROTTLE_MAX_DELAY = 10 # The average number of requests Scrapy should be sending in parallel to each remote server # 平均每秒并发数 # AUTOTHROTTLE_TARGET_CONCURRENCY = 1.0 # Enable showing throttling stats for every response received: # 是否显示 # AUTOTHROTTLE_DEBUG = True # Enable and configure HTTP caching (disabled by default) # See http://scrapy.readthedocs.org/en/latest/topics/downloader-middleware.html#httpcache-middleware-settings """ 18. 启用缓存 目的用于将已经发送的请求或相应缓存下来，以便以后使用 from scrapy.downloadermiddlewares.httpcache import HttpCacheMiddleware from scrapy.extensions.httpcache import DummyPolicy from scrapy.extensions.httpcache import FilesystemCacheStorage """ # 是否启用缓存策略 # HTTPCACHE_ENABLED = True # 缓存策略：所有请求均缓存，下次在请求直接访问原来的缓存即可 # HTTPCACHE_POLICY = "scrapy.extensions.httpcache.DummyPolicy" # 缓存策略：根据Http响应头：Cache-Control、Last-Modified 等进行缓存的策略 # HTTPCACHE_POLICY = "scrapy.extensions.httpcache.RFC2616Policy" # 缓存超时时间 # HTTPCACHE_EXPIRATION_SECS = 0 # 缓存保存路径 # HTTPCACHE_DIR = 'httpcache' # 缓存忽略的Http状态码 # HTTPCACHE_IGNORE_HTTP_CODES = [] # 缓存存储的插件 # HTTPCACHE_STORAGE = 'scrapy.extensions.httpcache.FilesystemCacheStorage' """ 19. 代理，需要在环境变量中设置 from scrapy.contrib.downloadermiddleware.httpproxy import HttpProxyMiddleware 方式一：使用默认 os.environ { http_proxy:http://root:woshiniba@192.168.11.11:9999/ https_proxy:http://192.168.11.11:9999/ } 方式二：使用自定义下载中间件 def to_bytes(text, encoding=None, errors='strict'): if isinstance(text, bytes): return text if not isinstance(text, six.string_types): raise TypeError('to_bytes must receive a unicode, str or bytes ' 'object, got %s' % type(text).__name__) if encoding is None: encoding = 'utf-8' return text.encode(encoding, errors) class ProxyMiddleware(object): def process_request(self, request, spider): PROXIES = [ {'ip_port': '111.11.228.75:80', 'user_pass': ''}, {'ip_port': '120.198.243.22:80', 'user_pass': ''}, {'ip_port': '111.8.60.9:8123', 'user_pass': ''}, {'ip_port': '101.71.27.120:80', 'user_pass': ''}, {'ip_port': '122.96.59.104:80', 'user_pass': ''}, {'ip_port': '122.224.249.122:8088', 'user_pass': ''}, ] proxy = random.choice(PROXIES) if proxy['user_pass'] is not None: request.meta['proxy'] = to_bytes（"http://%s" % proxy['ip_port']） encoded_user_pass = base64.encodestring(to_bytes(proxy['user_pass'])) request.headers['Proxy-Authorization'] = to_bytes('Basic ' + encoded_user_pass) print "**************ProxyMiddleware have pass************" + proxy['ip_port'] else: print "**************ProxyMiddleware no pass************" + proxy['ip_port'] request.meta['proxy'] = to_bytes("http://%s" % proxy['ip_port']) DOWNLOADER_MIDDLEWARES = { 'step8_king.middlewares.ProxyMiddleware': 500, } """ """ 20. Https访问 Https访问时有两种情况： 1. 要爬取网站使用的可信任证书(默认支持) DOWNLOADER_HTTPCLIENTFACTORY = "scrapy.core.downloader.webclient.ScrapyHTTPClientFactory" DOWNLOADER_CLIENTCONTEXTFACTORY = "scrapy.core.downloader.contextfactory.ScrapyClientContextFactory" 2. 要爬取网站使用的自定义证书 DOWNLOADER_HTTPCLIENTFACTORY = "scrapy.core.downloader.webclient.ScrapyHTTPClientFactory" DOWNLOADER_CLIENTCONTEXTFACTORY = "step8_king.https.MySSLFactory" # https.py from scrapy.core.downloader.contextfactory import ScrapyClientContextFactory from twisted.internet.ssl import (optionsForClientTLS, CertificateOptions, PrivateCertificate) class MySSLFactory(ScrapyClientContextFactory): def getCertificateOptions(self): from OpenSSL import crypto v1 = crypto.load_privatekey(crypto.FILETYPE_PEM, open('/Users/xyp/client.key.unsecure', mode='r').read()) v2 = crypto.load_certificate(crypto.FILETYPE_PEM, open('/Users/xyp/client.pem', mode='r').read()) return CertificateOptions( privateKey=v1, # pKey对象 certificate=v2, # X509对象 verify=False, method=getattr(self, 'method', getattr(self, '_ssl_method', None)) ) 其他： 相关类 scrapy.core.downloader.handlers.http.HttpDownloadHandler scrapy.core.downloader.webclient.ScrapyHTTPClientFactory scrapy.core.downloader.contextfactory.ScrapyClientContextFactory 相关配置 DOWNLOADER_HTTPCLIENTFACTORY DOWNLOADER_CLIENTCONTEXTFACTORY """ """ 21. 爬虫中间件 class SpiderMiddleware(object): def process_spider_input(self,response, spider): ''' 下载完成，执行，然后交给parse处理 :param response: :param spider: :return: ''' pass def process_spider_output(self,response, result, spider): ''' spider处理完成，返回时调用 :param response: :param result: :param spider: :return: 必须返回包含 Request 或 Item 对象的可迭代对象(iterable) ''' return result def process_spider_exception(self,response, exception, spider): ''' 异常调用 :param response: :param exception: :param spider: :return: None,继续交给后续中间件处理异常；含 Response 或 Item 的可迭代对象(iterable)，交给调度器或pipeline ''' return None def process_start_requests(self,start_requests, spider): ''' 爬虫启动时调用 :param start_requests: :param spider: :return: 包含 Request 对象的可迭代对象 ''' return start_requests 内置爬虫中间件： 'scrapy.contrib.spidermiddleware.httperror.HttpErrorMiddleware': 50, 'scrapy.contrib.spidermiddleware.offsite.OffsiteMiddleware': 500, 'scrapy.contrib.spidermiddleware.referer.RefererMiddleware': 700, 'scrapy.contrib.spidermiddleware.urllength.UrlLengthMiddleware': 800, 'scrapy.contrib.spidermiddleware.depth.DepthMiddleware': 900, """ # from scrapy.contrib.spidermiddleware.referer import RefererMiddleware # Enable or disable spider middlewares # See http://scrapy.readthedocs.org/en/latest/topics/spider-middleware.html SPIDER_MIDDLEWARES = { # 'step8_king.middlewares.SpiderMiddleware': 543, } """ 22. 下载中间件 class DownMiddleware1(object): def process_request(self, request, spider): ''' 请求需要被下载时，经过所有下载器中间件的process_request调用 :param request: :param spider: :return: None,继续后续中间件去下载； Response对象，停止process_request的执行，开始执行process_response Request对象，停止中间件的执行，将Request重新调度器 raise IgnoreRequest异常，停止process_request的执行，开始执行process_exception ''' pass def process_response(self, request, response, spider): ''' spider处理完成，返回时调用 :param response: :param result: :param spider: :return: Response 对象：转交给其他中间件process_response Request 对象：停止中间件，request会被重新调度下载 raise IgnoreRequest 异常：调用Request.errback ''' print('response1') return response def process_exception(self, request, exception, spider): ''' 当下载处理器(download handler)或 process_request() (下载中间件)抛出异常 :param response: :param exception: :param spider: :return: None：继续交给后续中间件处理异常； Response对象：停止后续process_exception方法 Request对象：停止中间件，request将会被重新调用下载 ''' return None 默认下载中间件 { 'scrapy.contrib.downloadermiddleware.robotstxt.RobotsTxtMiddleware': 100, 'scrapy.contrib.downloadermiddleware.httpauth.HttpAuthMiddleware': 300, 'scrapy.contrib.downloadermiddleware.downloadtimeout.DownloadTimeoutMiddleware': 350, 'scrapy.contrib.downloadermiddleware.useragent.UserAgentMiddleware': 400, 'scrapy.contrib.downloadermiddleware.retry.RetryMiddleware': 500, 'scrapy.contrib.downloadermiddleware.defaultheaders.DefaultHeadersMiddleware': 550, 'scrapy.contrib.downloadermiddleware.redirect.MetaRefreshMiddleware': 580, 'scrapy.contrib.downloadermiddleware.httpcompression.HttpCompressionMiddleware': 590, 'scrapy.contrib.downloadermiddleware.redirect.RedirectMiddleware': 600, 'scrapy.contrib.downloadermiddleware.cookies.CookiesMiddleware': 700, 'scrapy.contrib.downloadermiddleware.httpproxy.HttpProxyMiddleware': 750, 'scrapy.contrib.downloadermiddleware.chunked.ChunkedTransferMiddleware': 830, 'scrapy.contrib.downloadermiddleware.stats.DownloaderStats': 850, 'scrapy.contrib.downloadermiddleware.httpcache.HttpCacheMiddleware': 900, } """ # from scrapy.contrib.downloadermiddleware.httpauth import HttpAuthMiddleware # Enable or disable downloader middlewares # See http://scrapy.readthedocs.org/en/latest/topics/downloader-middleware.html # DOWNLOADER_MIDDLEWARES = { # 'step8_king.middlewares.DownMiddleware1': 100, # 'step8_king.middlewares.DownMiddleware2': 500, # }
