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 pip install scrapyWindows a. pip install wheel b. 下载twisted http://www.lfd.uci.edu/~gohlke/pythonlibs/#twisted c. 进入下载目录，执行 pip3 install Twisted‑17.1.0‑cp35‑cp35m‑win_amd64.whl d. pip install scrapy e. 下载并安装pywin32：https://sourceforge.net/projects/pywin32/files/二、基本使用
1. 基本命令
1. scrapy startproject 项目名称 - 在当前目录中创建中创建一个项目文件（类似于Django）2. scrapy genspider [-t template] <name> <domain> - 创建爬虫应用 如： scrapy gensipider -t basic oldboy oldboy.com scrapy gensipider -t xmlfeed autohome autohome.com.cn 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 list - 展示爬虫应用列表4. scrapy crawl 爬虫应用名称 - 运行单独爬虫应用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
1 import scrapy 2 3 class XiaoHuarSpider(scrapy.spiders.Spider): 4 name = "xiaohuar" # 爬虫名称 ***** 5 allowed_domains = ["xiaohuar.com"] # 允许的域名 6 start_urls = [ 7 "http://www.xiaohuar.com/hua/", # 其实URL 8 ] 9 10 def parse(self, response): 11 # 访问起始URL并获取结果后的回调函数 12 13 爬虫1.py
import sys,os sys.stdout=io.TextIOWrapper(sys.stdout.buffer,encoding='gb18030')
1 import scrapy 2 from scrapy.selector import HtmlXPathSelector 3 from scrapy.http.request import Request 4 5 6 class DigSpider(scrapy.Spider): 7 # 爬虫应用的名称，通过此名称启动爬虫命令 8 name = "dig" 9 10 # 允许的域名 11 allowed_domains = ["chouti.com"] 12 13 # 起始URL 14 start_urls = [ 15 'http://dig.chouti.com/', 16 ] 17 18 has_request_set = {} 19 20 def parse(self, response): 21 print(response.url) 22 23 hxs = HtmlXPathSelector(response) 24 page_list = hxs.select('//div[@id="dig_lcpage"]//a[re:test(@href, "/all/hot/recent/\d+")]/@href').extract() 25 for page in page_list: 26 page_url = 'http://dig.chouti.com%s' % page 27 key = self.md5(page_url) 28 if key in self.has_request_set: 29 pass 30 else: 31 self.has_request_set[key] = page_url 32 obj = Request(url=page_url, method='GET', callback=self.parse) 33 yield obj 34 35 @staticmethod 36 def md5(val): 37 import hashlib 38 ha = hashlib.md5() 39 ha.update(bytes(val, encoding='utf-8')) 40 key = ha.hexdigest() 41 return key
执行此爬虫文件，则在终端进入项目目录执行如下命令：
scrapy crawl dig --nolog
对于上述代码重要之处在于：
- 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
1 #!/usr/bin/env python 2 # -*- coding:utf-8 -*- 3 from scrapy.selector import Selector, HtmlXPathSelector 4 from scrapy.http import HtmlResponse 5 html = """<!DOCTYPE html> 6 <html> 7 <head lang="en"> 8 <meta charset="UTF-8"> 9 <title></title> 10 </head> 11 <body> 12 <ul> 13 <li class="item-"><a id='i1' href="link.html">first item</a></li> 14 <li class="item-0"><a id='i2' href="llink.html">first item</a></li> 15 <li class="item-1"><a href="llink2.html">second item<span>vv</span></a></li> 16 </ul> 17 <div><a href="llink2.html">second item</a></div> 18 </body> 19 </html> 20 """ 21 response = HtmlResponse(url='http://example.com', body=html,encoding='utf-8') 22 # hxs = HtmlXPathSelector(response) 23 # print(hxs) 24 # hxs = Selector(response=response).xpath('//a') 25 # print(hxs) 26 # hxs = Selector(response=response).xpath('//a[2]') 27 # print(hxs) 28 # hxs = Selector(response=response).xpath('//a[@id]') 29 # print(hxs) 30 # hxs = Selector(response=response).xpath('//a[@id="i1"]') 31 # print(hxs) 32 # hxs = Selector(response=response).xpath('//a[@href="link.html"][@id="i1"]') 33 # print(hxs) 34 # hxs = Selector(response=response).xpath('//a[contains(@href, "link")]') 35 # print(hxs) 36 # hxs = Selector(response=response).xpath('//a[starts-with(@href, "link")]') 37 # print(hxs) 38 # hxs = Selector(response=response).xpath('//a[re:test(@id, "i\d+")]') 39 # print(hxs) 40 # hxs = Selector(response=response).xpath('//a[re:test(@id, "i\d+")]/text()').extract() 41 # print(hxs) 42 # hxs = Selector(response=response).xpath('//a[re:test(@id, "i\d+")]/@href').extract() 43 # print(hxs) 44 # hxs = Selector(response=response).xpath('/html/body/ul/li/a/@href').extract() 45 # print(hxs) 46 # hxs = Selector(response=response).xpath('//body/ul/li/a/@href').extract_first() 47 # print(hxs) 48 49 # ul_list = Selector(response=response).xpath('//body/ul/li') 50 # for item in ul_list: 51 # v = item.xpath('./a/span') 52 # # 或 53 # # v = item.xpath('a/span') 54 # # 或 55 # # v = item.xpath('*/a/span') 56 # print(v)
1 # -*- coding: utf-8 -*- 2 import scrapy 3 from scrapy.selector import HtmlXPathSelector 4 from scrapy.http.request import Request 5 from scrapy.http.cookies import CookieJar 6 from scrapy import FormRequest 7 8 9 class ChouTiSpider(scrapy.Spider): 10 # 爬虫应用的名称，通过此名称启动爬虫命令 11 name = "chouti" 12 # 允许的域名 13 allowed_domains = ["chouti.com"] 14 15 cookie_dict = {} 16 has_request_set = {} 17 18 def start_requests(self): 19 url = 'http://dig.chouti.com/' 20 # return [Request(url=url, callback=self.login)] 21 yield Request(url=url, callback=self.login) 22 23 def login(self, response): 24 cookie_jar = CookieJar() 25 cookie_jar.extract_cookies(response, response.request) 26 for k, v in cookie_jar._cookies.items(): 27 for i, j in v.items(): 28 for m, n in j.items(): 29 self.cookie_dict[m] = n.value 30 31 req = Request( 32 url='http://dig.chouti.com/login', 33 method='POST', 34 headers={'Content-Type': 'application/x-www-form-urlencoded; charset=UTF-8'}, 35 body='phone=8615131255089&password=pppppppp&oneMonth=1', 36 cookies=self.cookie_dict, 37 callback=self.check_login 38 ) 39 yield req 40 41 def check_login(self, response): 42 req = Request( 43 url='http://dig.chouti.com/', 44 method='GET', 45 callback=self.show, 46 cookies=self.cookie_dict, 47 dont_filter=True 48 ) 49 yield req 50 51 def show(self, response): 52 # print(response) 53 hxs = HtmlXPathSelector(response) 54 news_list = hxs.select('//div[@id="content-list"]/div[@class="item"]') 55 for new in news_list: 56 # temp = new.xpath('div/div[@class="part2"]/@share-linkid').extract() 57 link_id = new.xpath('*/div[@class="part2"]/@share-linkid').extract_first() 58 yield Request( 59 url='http://dig.chouti.com/link/vote?linksId=%s' %(link_id,), 60 method='POST', 61 cookies=self.cookie_dict, 62 callback=self.do_favor 63 ) 64 65 page_list = hxs.select('//div[@id="dig_lcpage"]//a[re:test(@href, "/all/hot/recent/\d+")]/@href').extract() 66 for page in page_list: 67 68 page_url = 'http://dig.chouti.com%s' % page 69 import hashlib 70 hash = hashlib.md5() 71 hash.update(bytes(page_url,encoding='utf-8')) 72 key = hash.hexdigest() 73 if key in self.has_request_set: 74 pass 75 else: 76 self.has_request_set[key] = page_url 77 yield Request( 78 url=page_url, 79 method='GET', 80 callback=self.show 81 ) 82 83 def do_favor(self, response): 84 print(response.text) 85 86 示例：自动登陆抽屉并点赞
格式化处理
1 import scrapy 2 from scrapy.selector import HtmlXPathSelector 3 from scrapy.http.request import Request 4 from scrapy.http.cookies import CookieJar 5 from scrapy import FormRequest 6 7 8 class XiaoHuarSpider(scrapy.Spider): 9 # 爬虫应用的名称，通过此名称启动爬虫命令 10 name = "xiaohuar" 11 # 允许的域名 12 allowed_domains = ["xiaohuar.com"] 13 14 start_urls = [ 15 "http://www.xiaohuar.com/list-1-1.html", 16 ] 17 # custom_settings = { 18 # 'ITEM_PIPELINES':{ 19 # 'spider1.pipelines.JsonPipeline': 100 20 # } 21 # } 22 has_request_set = {} 23 24 def parse(self, response): 25 # 分析页面 26 # 找到页面中符合规则的内容（校花图片），保存 27 # 找到所有的a标签，再访问其他a标签，一层一层的搞下去 28 29 hxs = HtmlXPathSelector(response) 30 31 items = hxs.select('//div[@class="item_list infinite_scroll"]/div') 32 for item in items: 33 src = item.select('.//div[@class="img"]/a/img/@src').extract_first() 34 name = item.select('.//div[@class="img"]/span/text()').extract_first() 35 school = item.select('.//div[@class="img"]/div[@class="btns"]/a/text()').extract_first() 36 url = "http://www.xiaohuar.com%s" % src 37 from ..items import XiaoHuarItem 38 obj = XiaoHuarItem(name=name, school=school, url=url) 39 yield obj 40 41 urls = hxs.select('//a[re:test(@href, "http://www.xiaohuar.com/list-1-\d+.html")]/@href') 42 for url in urls: 43 key = self.md5(url) 44 if key in self.has_request_set: 45 pass 46 else: 47 self.has_request_set[key] = url 48 req = Request(url=url,method='GET',callback=self.parse) 49 yield req 50 51 @staticmethod 52 def md5(val): 53 import hashlib 54 ha = hashlib.md5() 55 ha.update(bytes(val, encoding='utf-8')) 56 key = ha.hexdigest() 57 return key 58 59 spiders/xiahuar.py
1 import scrapy 2 3 4 class XiaoHuarItem(scrapy.Item): 5 name = scrapy.Field() 6 school = scrapy.Field() 7 url = scrapy.Field()
1 import json 2 import os 3 import requests 4 5 6 class JsonPipeline(object): 7 def __init__(self): 8 self.file = open('xiaohua.txt', 'w') 9 10 def process_item(self, item, spider): 11 v = json.dumps(dict(item), ensure_ascii=False) 12 self.file.write(v) 13 self.file.write('\n') 14 self.file.flush() 15 return item 16 17 18 class FilePipeline(object): 19 def __init__(self): 20 if not os.path.exists('imgs'): 21 os.makedirs('imgs') 22 23 def process_item(self, item, spider): 24 response = requests.get(item['url'], stream=True) 25 file_name = '%s_%s.jpg' % (item['name'], item['school']) 26 with open(os.path.join('imgs', file_name), mode='wb') as f: 27 f.write(response.content) 28 return item
ITEM_PIPELINES = {
'spider1.pipelines.JsonPipeline': 100,
'spider1.pipelines.FilePipeline': 300,
}
# 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。
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')
自定义pipeline
中间件
1 class SpiderMiddleware(object): 2 3 def process_spider_input(self,response, spider): 4 """ 5 下载完成，执行，然后交给parse处理 6 :param response: 7 :param spider: 8 :return: 9 """ 10 pass 11 12 def process_spider_output(self,response, result, spider): 13 """ 14 spider处理完成，返回时调用 15 :param response: 16 :param result: 17 :param spider: 18 :return: 必须返回包含 Request 或 Item 对象的可迭代对象(iterable) 19 """ 20 return result 21 22 def process_spider_exception(self,response, exception, spider): 23 """ 24 异常调用 25 :param response: 26 :param exception: 27 :param spider: 28 :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 29 """ 30 return None 31 32 33 def process_start_requests(self,start_requests, spider): 34 """ 35 爬虫启动时调用 36 :param start_requests: 37 :param spider: 38 :return: 包含 Request 对象的可迭代对象 39 """ 40 return start_requests
1 class DownMiddleware1(object): 2 def process_request(self, request, spider): 3 """ 4 请求需要被下载时，经过所有下载器中间件的process_request调用 5 :param request: 6 :param spider: 7 :return: 8 None,继续后续中间件去下载； 9 Response对象，停止process_request的执行，开始执行process_response 10 Request对象，停止中间件的执行，将Request重新调度器 11 raise IgnoreRequest异常，停止process_request的执行，开始执行process_exception 12 """ 13 pass 14 15 16 17 def process_response(self, request, response, spider): 18 """ 19 spider处理完成，返回时调用 20 :param response: 21 :param result: 22 :param spider: 23 :return: 24 Response 对象：转交给其他中间件process_response 25 Request 对象：停止中间件，request会被重新调度下载 26 raise IgnoreRequest 异常：调用Request.errback 27 """ 28 print('response1') 29 return response 30 31 def process_exception(self, request, exception, spider): 32 """ 33 当下载处理器(download handler)或 process_request() (下载中间件)抛出异常 34 :param response: 35 :param exception: 36 :param spider: 37 :return: 38 None：继续交给后续中间件处理异常； 39 Response对象：停止后续process_exception方法 40 Request对象：停止中间件，request将会被重新调用下载 41 """ 42 return None
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
自定义扩展
自定义扩展时，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)
crawler.signals.connect(ext.spider_opened, signal=signals.spider_opened)
crawler.signals.connect(ext.spider_closed, signal=signals.spider_closed)
return ext
def spider_opened(self, spider):
print('open')
def spider_closed(self, spider):
print('close')
避免重复访问
scrapy默认使用 scrapy.dupefilter.RFPDupeFilter 进行去重，相关配置有：
DUPEFILTER_CLASS = 'scrapy.dupefilter.RFPDupeFilter'DUPEFILTER_DEBUG = FalseJOBDIR = "保存范文记录的日志路径，如：/root/" # 最终路径为 /root/requests.seenclass RepeatUrl:
def __init__(self):
self.visited_url = set()
@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)
自定义URL去重操作
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,
# }
settings
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()
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