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, 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)。或者发送新的请求 - 项目管道(Pipeline)
在items被提取后负责处理它们,主要包括清理、验证、持久化(比如存到数据库)等操作 - 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。(最新版本,没有了)
概括scrapy框架分成几部分:
爬虫,引擎,pipeline,调度器,下载器
持久化:通俗的讲,就是瞬时数据持久化为持久数据。主要应用是将内存中的对象存储在数据库中,或者存储在磁盘文件中、XML数据文件中等等
Scrapy运行流程大概如下:
1.引擎从调度器中取出一个链接(URL)用于接下来的抓取
2.引擎把URL封装成一个请求(Request)传给下载器
3.下载器把资源下载下来,并封装成应答包(Response)
4.爬虫解析Response
5.解析出实体(Item),则交给管道进行进一步的处理
6.解析出的是 链接(URL),则把URL交给调度器等待抓取
一.基本使用
1.基本命令
1. 创建爬虫项目 scrapy startproject 项目名称 - scrapy startproject sp1 2.创建爬虫应用 cd sp1 scrapy genspider baidu baidu.com PS: 查看所有命令:scrapy gensipider -l 查看模板命令:scrapy gensipider -d 模板名称 3. scrapy crawl 爬虫应用名称 - 运行单独爬虫应用 4. scrapy list - 展示爬虫应用列表
2.项目结构以及爬虫应用简介
project_name/ scrapy.cfg project_name/ __init__.py items.py pipelines.py settings.py spiders/ __init__.py 爬虫1.py 爬虫2.py 爬虫3.py
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
import scrapy class XiaoHuarSpider(scrapy.spiders.Spider): name = "xiaohuar" # 爬虫名称 ***** allowed_domains = ["xiaohuar.com"] # 允许的域名 start_urls = [ "http://www.xiaohuar.com/hua/", # 其实URL ] def parse(self, response): # 访问起始URL并获取结果后的回调函数
import sys,os sys.stdout=io.TextIOWrapper(sys.stdout.buffer,encoding='gb18030')
3.小试牛刀
# -*- coding: utf-8 -*- import scrapy from scrapy.selector import HtmlXPathSelector from scrapy.http.request import Request class ChoutiSpider(scrapy.Spider): # scrapy crawl chouti --nolog,启动爬虫命令 name = 'chouti' #允许的域名 allowed_domains = ['chouti.com'] #起始URL start_urls = ['http://chouti.com/'] has_request_set = {} def parse(self, response): print('response.url',response.url) hxs = HtmlXPathSelector(response) page_list = hxs.select('//div[@id="dig_lcpage"]//a[re:test(@href,"/all/hot/recent/d+")]/@href').extract() for page in page_list: page_url = 'http://dig.chouti.com%s'%page key = self.md5(page_url) if key in self.has_request_set: pass else: self.has_request_set[key] = page_url obj = Request(url=page_url, method='GET', callback=self.parse) yield obj @staticmethod def md5(val): import hashlib ha = hashlib.md5() ha.update(bytes(val, encoding='utf-8')) key = ha.hexdigest() return key
对于上述代码重要之处:
- Request是一个封装用户请求的类,在回调函数中yield该对象表示继续访问
- HtmlXpathSelector用于结构化HTML代码并提供选择器功能
4.Scrapy定制起始URL函数
#-------------标配 import scrapy class BaiduSpider(scrapy.Spider): name = 'baidu' allowed_domains = ['baidu.com'] start_urls = ['http://baidu.com/'] def parse(self, response): print(response.text) #-------------自定制 import scrapy from scrapy.http import Request class ChoutiSpider(scrapy.Spider): name = 'chouti' allowed_domains = ['chouti.com'] start_urls = ['http://chouti.com/'] def start_requests(self): ##返回 可迭代对象或生成器 for url in self.start_urls: yield Request(url, dont_filter=True, callback=self.parse1) def parse1(self, response): pass
5.POST请求,请求头,cookie
requests.get(params={}, headers={}, cookies={}) requests.post(params={}, headers={}, cookies={}, data={}, json={})
GET请求: url, method='GET', headers={}, cookies={}, cookiejar POST请求: url, method='GET', headers={}, cookies={}, cookiejar body=None, #请求头格式一 application/x-www-form-urlencoded; charset=UTF-8 form_data = { 'user':'Tom', 'pwd': 123 } import urllib.parse data = urllib.parse.urlencode({'k1':'v1','k2':'v2'}) 结果:"k1=v1&k2=v3" #请求头格式二 application/json; charset=UTF-8 json.dumsp() "{k1:'v1','k2':'v2'}" 示例: Request( url='http://dig.chouti.com/login', method='POST', headers={'Content-Type': 'application/x-www-form-urlencoded; charset=UTF-8'}, body='phone=861517243291&password=pppppppp&oneMonth=1', callback=self.check_login )
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 3. 为所欲为,携带cookie """ 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 from scrapy.http.cookies import CookieJar cookie_jar = CookieJar() # 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, body=urllib.parse.urlencode(post_dict), headers={'Content-Type':'application/x-www-form-urlencoded; charset=UTF-8'}, callback=self.parse2 )
5.选择器
5.格式化处理
上述实例只是简单的处理,所以在parse方法中直接处理。如果对于想要获取更多的数据处理,则可以利用Scrapy的items将数据格式化,然后统一交由pipelines来处理。
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) # 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()
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') #settings 设置 数据库 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() #再加个一个 class Sp3Pipeline(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 @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, 'sp2.pipelines.Sp3Pipeline': 100, } # 每行后面的整型值,确定了他们运行的顺序,item按数字从低到高的顺序,通过pipeline,通常将这些数字定义在0-1000范围内。(越小越优先)
对于pipeline可以做更多,如下:
from scrapy.exceptions import DropItem class CustomPipeline(object): def __init__(self,v): self.value = v 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.getint('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from_crawler方法,yield item obj.process_item() obj.close_spider() """
6.去重
scrapy默认使用 scrapy.dupefilter.RFPDupeFilter 进行去重,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
自定义URL去重:
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)
在settings.py配置:
DUPEFILTER_CLASS = 'sp1.rep.RepeatUrl'
7.基于信号自定义扩展
利用信号在指定位置注册制定操作
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) # 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('基于信号:open') def closed(self, spider): print('基于信号:close') #settings.py 配置 # EXTENSIONS = { # 'sp1.extends.MyExtension': 100, # }
#Django的信号:给我们预留的扩展功能。
就是一些动作发生的时候,信号允许特定的发送者去提醒一些接受者。
8.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
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 """ #最重要的两种情况 """ 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 """ 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') # from scrapy.http import Response # response.encoding = 'utf-8' 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
9.自定制命令
- 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)
from scrapy.commands import ScrapyCommand from scrapy.utils.project import get_project_settings 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): spider_list = self.crawler_process.spiders.list() for name in spider_list: self.crawler_process.crawl(name, **opts.__dict__) self.crawler_process.start()
- 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
10.代理
本质就是设置请求头
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, } """
#源码(了解)
从模块 进入源码: from scrapy.downloadermiddlewares.httpproxy import HttpProxyMiddleware 源码: def _set_proxy(self, request, scheme): creds, proxy = self.proxies[scheme] #第一个 授权,第二个 代理 request.meta['proxy'] = proxy if creds: request.headers['Proxy-Authorization'] = b'Basic ' + creds from urllib.request import getproxies 源码: # Proxy handling def getproxies_environment(): proxies = {} for name, value in os.environ.items(): name = name.lower() if value and name[-6:] == '_proxy': proxies[name[:-6]] = value if 'REQUEST_METHOD' in os.environ: proxies.pop('http', None) for name, value in os.environ.items(): if name[-6:] == '_proxy': #------》【-6】 name = name.lower() if value: proxies[name[:-6]] = value else: proxies.pop(name[:-6], None) return proxies
11、其他
# -*- 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)' # Obey robots.txt rules # 4. 禁止爬虫配置 # ROBOTSTXT_OBEY = False # 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: # 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... # 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 # 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' # 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/wupeiqi/client.key.unsecure', mode='r').read()) v2 = crypto.load_certificate(crypto.FILETYPE_PEM, open('/Users/wupeiqi/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, # }
12.TinyScrapy
#!/usr/bin/env python # -*- coding:utf-8 -*- import types from twisted.internet import defer from twisted.web.client import getPage from twisted.internet import reactor class Request(object): def __init__(self, url, callback): self.url = url self.callback = callback self.priority = 0 class HttpResponse(object): def __init__(self, content, request): self.content = content self.request = request class ChouTiSpider(object): def start_requests(self): url_list = ['http://www.cnblogs.com/', 'http://www.bing.com'] for url in url_list: yield Request(url=url, callback=self.parse) def parse(self, response): print(response.request.url) # yield Request(url="http://www.baidu.com", callback=self.parse) from queue import Queue Q = Queue() class CallLaterOnce(object): def __init__(self, func, *a, **kw): self._func = func self._a = a self._kw = kw self._call = None def schedule(self, delay=0): if self._call is None: self._call = reactor.callLater(delay, self) def cancel(self): if self._call: self._call.cancel() def __call__(self): self._call = None return self._func(*self._a, **self._kw) class Engine(object): def __init__(self): self.nextcall = None self.crawlling = [] self.max = 5 self._closewait = None def get_response(self,content, request): response = HttpResponse(content, request) gen = request.callback(response) if isinstance(gen, types.GeneratorType): for req in gen: req.priority = request.priority + 1 Q.put(req) def rm_crawlling(self,response,d): self.crawlling.remove(d) def _next_request(self,spider): if Q.qsize() == 0 and len(self.crawlling) == 0: self._closewait.callback(None) if len(self.crawlling) >= 5: return while len(self.crawlling) < 5: try: req = Q.get(block=False) except Exception as e: req = None if not req: return d = getPage(req.url.encode('utf-8')) self.crawlling.append(d) d.addCallback(self.get_response, req) d.addCallback(self.rm_crawlling,d) d.addCallback(lambda _: self.nextcall.schedule()) @defer.inlineCallbacks def crawl(self): spider = ChouTiSpider() start_requests = iter(spider.start_requests()) flag = True while flag: try: req = next(start_requests) Q.put(req) except StopIteration as e: flag = False self.nextcall = CallLaterOnce(self._next_request,spider) self.nextcall.schedule() self._closewait = defer.Deferred() yield self._closewait @defer.inlineCallbacks def pp(self): yield self.crawl() _active = set() obj = Engine() d = obj.crawl() _active.add(d) li = defer.DeferredList(_active) li.addBoth(lambda _,*a,**kw: reactor.stop()) reactor.run()
#额外拿出--注释
#!/usr/bin/env python # -*- coding:utf-8 -*- import types from twisted.internet import defer from twisted.web.client import getPage from twisted.internet import reactor from queue import Queue class Request(object): """ 封装请求相关信息 """ def __init__(self, url, callback): self.url = url self.callback = callback self.priority = 0 class HttpResponse(object): """ 封装相应相关信息 """ def __init__(self, content, request): self.content = content self.request = request class Scheduler(object): """ 任务调度器 """ def __init__(self): self.q = Queue() def open(self): pass def next_request(self): try: request = self.q.get(block=False) except Exception as e: request = None return request def enqueue_request(self, request): self.q.put(request,block=False) def size(self): return self.q.qsize() class CallLaterOnce(object): """ 用于封装:执行下次nextcall.schedule()时,可以携带spider参数 """ def __init__(self, func, *a, **kw): self._func = func self._a = a self._kw = kw self._call = None def schedule(self, delay=0): if self._call is None: self._call = reactor.callLater(delay, self) def cancel(self): if self._call: self._call.cancel() def __call__(self): self._call = None return self._func(*self._a, **self._kw) class ExecutionEngine(object): def __init__(self, crawler): self.crawler = crawler self.nextcall = None self.crawlling = [] self.max = 5 self._closewait = None self.scheduler = None def get_response(self, content, request): response = HttpResponse(content, request) gen = request.callback(response) if isinstance(gen, types.GeneratorType): for req in gen: req.priority = request.priority + 1 self.scheduler.enqueue_request(req) def _next_request(self, spider): if self.scheduler.size() == 0 and len(self.crawlling) == 0: self._closewait.callback(None) if len(self.crawlling) >= 5: return while len(self.crawlling) < 5: req = self.scheduler.next_request() if not req: return d = getPage(req.url.encode('utf-8')) self.crawlling.append(d) #执行回调函数且向调度器中添加yield返回的request对象 d.addCallback(self.get_response, req) #去掉 d.addCallback(lambda _,d:self.crawlling.remove(d), d) #再去调度器中获取一个人物,继续执行下载(递归执行_next_request:这里的递归是说,执行一次在执行一次) d.addCallback(lambda _: self.nextcall.schedule()) @defer.inlineCallbacks def open_spider(self, spider, start_requests): self.scheduler = Scheduler() flag = True while flag: try: req = next(start_requests) self.scheduler.enqueue_request(req) except StopIteration as e: flag = False self.nextcall = CallLaterOnce(self._next_request, spider) self.nextcall.schedule() yield None @defer.inlineCallbacks def start(self): self._closewait = defer.Deferred() yield self._closewait class Crawler(object): def __init__(self, spider_cls_path, settings): self.spider_cls_path = spider_cls_path self.settings = settings self.spider = None self.engine = None def _create_spider(self): """ 创建爬虫对象 :return: """ module_path, cls_name = self.spider_cls_path.rsplit('.', maxsplit=1) import importlib m = importlib.import_module(module_path) cls = getattr(m, cls_name) return cls() def _create_engine(self): """ 创建引擎 :return: """ return ExecutionEngine(self) @defer.inlineCallbacks def crawl(self): """ :param args: :param kwargs: :return: """ self.spider = self._create_spider() self.engine = self._create_engine() start_requests = iter(self.spider.start_requests()) #去获取数据 yield self.engine.open_spider(self.spider, start_requests) #hold住请求,不终止 yield self.engine.start() # _closewait.callback(None) 直到有此操作,才全部结束 class CrawlerProcess(object): def __init__(self, settings): self.settings = settings self._active = set() self.crawlers = set() def crawl(self, spider_cls_path): """ 创建Crawler对象 :param spider_cls_path: 爬虫spider路径 :param args: :param kwargs: :return: """ crawler = Crawler(spider_cls_path, self.settings) #实例化对象 d = crawler.crawl() # defer.Deferred() ----返回defer对象 self._active.add(d) #d 加到 _active。若执行完,_active里只有一个值,一个 defer对象 def _done(result): self.crawlers.discard(crawler) self._active.discard(d) return result return d.addBoth(_done) def start(self): """ 所有爬虫开始工作 :return: """ dl = defer.DeferredList(self._active) dl.addBoth(self._stop_reactor) reactor.run() def _stop_reactor(self, _=None): """ 爬虫爬去数据完毕 :return: """ reactor.stop() class Commond(object): def __init__(self): self.crawl_process = CrawlerProcess({}) def run(self): # spider_path_list = [ # "spider.chouti.ChoutiSpider", # "spider.cnblogs.CnblogsSpider", # ] # for spider_cls_path in spider_path_list: # self.crawl_process.crawl(spider_cls_path) self.crawl_process.crawl('spider.chouti.ChoutiSpider') #只是当做 字符串,并未 实例化 self.crawl_process.start() if __name__ == '__main__': cmd = Commond() #如果是主函数,实例化一个对象 cmd.run()