目录
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
1 2 3 4 5 6 7 8 9 10 | Linux pip3 install scrapyWindows a. pip3 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. pip3 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 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 | 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
1 2 3 4 5 6 7 8 9 10 11 12 | 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
爬虫1.py
import sys,os
sys.stdout=io.TextIOWrapper(sys.stdout.buffer,encoding='gb18030')
关于windows编码
3. 小试牛刀
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 | import scrapyfrom scrapy.selector import HtmlXPathSelectorfrom scrapy.http.request import Requestclass DigSpider(scrapy.Spider): # 爬虫应用的名称，通过此名称启动爬虫命令 name = "dig" # 允许的域名 allowed_domains = ["chouti.com"] # 起始URL start_urls = [ 'http://dig.chouti.com/', ] has_request_set = {} def parse(self, response): print(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 |
执行此爬虫文件，则在终端进入项目目录执行如下命令：
1 | 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
4. 选择器
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 | #!/usr/bin/env python# -*- coding:utf-8 -*-from scrapy.selector import Selector, HtmlXPathSelectorfrom scrapy.http import HtmlResponsehtml = """<!DOCTYPE html><html> <head lang="en"> <meta charset="UTF-8"> <title></title> </head> <body> <ul> <li class="item-"><a id='i1' href="link.html">first item</a></li> <li class="item-0"><a id='i2' href="llink.html">first item</a></li> <li class="item-1"><a href="llink2.html">second item<span>vv</span></a></li> </ul> <div><a href="llink2.html">second item</a></div> </body></html>"""response = HtmlResponse(url='http://example.com', body=html,encoding='utf-8')# hxs = HtmlXPathSelector(response)# print(hxs)# hxs = Selector(response=response).xpath('//a')# print(hxs)# hxs = Selector(response=response).xpath('//a[2]')# print(hxs)# hxs = Selector(response=response).xpath('//a[@id]')# print(hxs)# hxs = Selector(response=response).xpath('//a[@id="i1"]')# print(hxs)# hxs = Selector(response=response).xpath('//a[@href="link.html"][@id="i1"]')# print(hxs)# hxs = Selector(response=response).xpath('//a[contains(@href, "link")]')# print(hxs)# hxs = Selector(response=response).xpath('//a[starts-with(@href, "link")]')# print(hxs)# hxs = Selector(response=response).xpath('//a[re:test(@id, "i\d+")]')# print(hxs)# hxs = Selector(response=response).xpath('//a[re:test(@id, "i\d+")]/text()').extract()# print(hxs)# hxs = Selector(response=response).xpath('//a[re:test(@id, "i\d+")]/@href').extract()# print(hxs)# hxs = Selector(response=response).xpath('/html/body/ul/li/a/@href').extract()# print(hxs)# hxs = Selector(response=response).xpath('//body/ul/li/a/@href').extract_first()# print(hxs)# ul_list = Selector(response=response).xpath('//body/ul/li')# for item in ul_list:# v = item.xpath('./a/span')# # 或# # v = item.xpath('a/span')# # 或# # v = item.xpath('*/a/span')# print(v) |
# -*- coding: utf-8 -*-
import scrapy
from scrapy.selector import HtmlXPathSelector
from scrapy.http.request import Request
from scrapy.http.cookies import CookieJar
from scrapy import FormRequest class ChouTiSpider(scrapy.Spider):
# 爬虫应用的名称，通过此名称启动爬虫命令
name = "chouti"
# 允许的域名
allowed_domains = ["chouti.com"] cookie_dict = {}
has_request_set = {} def start_requests(self):
url = 'http://dig.chouti.com/'
# return [Request(url=url, callback=self.login)]
yield Request(url=url, callback=self.login) def login(self, response):
cookie_jar = CookieJar()
cookie_jar.extract_cookies(response, response.request)
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 req = 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
)
yield req def check_login(self, response):
req = Request(
url='http://dig.chouti.com/',
method='GET',
callback=self.show,
cookies=self.cookie_dict,
dont_filter=True
)
yield req def show(self, response):
# print(response)
hxs = HtmlXPathSelector(response)
news_list = hxs.select('//div[@id="content-list"]/div[@class="item"]')
for new in news_list:
# temp = new.xpath('div/div[@class="part2"]/@share-linkid').extract()
link_id = new.xpath('*/div[@class="part2"]/@share-linkid').extract_first()
yield Request(
url='http://dig.chouti.com/link/vote?linksId=%s' %(link_id,),
method='POST',
cookies=self.cookie_dict,
callback=self.do_favor
) 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
import hashlib
hash = hashlib.md5()
hash.update(bytes(page_url,encoding='utf-8'))
key = hash.hexdigest()
if key in self.has_request_set:
pass
else:
self.has_request_set[key] = page_url
yield Request(
url=page_url,
method='GET',
callback=self.show
) def do_favor(self, response):
print(response.text)
示例：自动登陆抽屉并点赞
注意：settings.py中设置DEPTH_LIMIT = 1来指定“递归”的层数。
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.selector import HtmlXPathSelector
from scrapy.http.request import Request
from scrapy.http.cookies import CookieJar
from scrapy import FormRequest class XiaoHuarSpider(scrapy.Spider):
# 爬虫应用的名称，通过此名称启动爬虫命令
name = "xiaohuar"
# 允许的域名
allowed_domains = ["xiaohuar.com"] start_urls = [
"http://www.xiaohuar.com/list-1-1.html",
]
# custom_settings = {
# 'ITEM_PIPELINES':{
# 'spider1.pipelines.JsonPipeline': 100
# }
# }
has_request_set = {} def parse(self, response):
# 分析页面
# 找到页面中符合规则的内容（校花图片），保存
# 找到所有的a标签，再访问其他a标签，一层一层的搞下去 hxs = HtmlXPathSelector(response) items = hxs.select('//div[@class="item_list infinite_scroll"]/div')
for item in items:
src = item.select('.//div[@class="img"]/a/img/@src').extract_first()
name = item.select('.//div[@class="img"]/span/text()').extract_first()
school = item.select('.//div[@class="img"]/div[@class="btns"]/a/text()').extract_first()
url = "http://www.xiaohuar.com%s" % src
from ..items import XiaoHuarItem
obj = XiaoHuarItem(name=name, school=school, url=url)
yield obj urls = hxs.select('//a[re:test(@href, "http://www.xiaohuar.com/list-1-\d+.html")]/@href')
for url in urls:
key = self.md5(url)
if key in self.has_request_set:
pass
else:
self.has_request_set[key] = url
req = Request(url=url,method='GET',callback=self.parse)
yield req @staticmethod
def md5(val):
import hashlib
ha = hashlib.md5()
ha.update(bytes(val, encoding='utf-8'))
key = ha.hexdigest()
return key
spiders/xiahuar.py
import scrapy class XiaoHuarItem(scrapy.Item):
name = scrapy.Field()
school = scrapy.Field()
url = scrapy.Field()
items
import json
import os
import requests class JsonPipeline(object):
def __init__(self):
self.file = open('xiaohua.txt', 'w') def process_item(self, item, spider):
v = json.dumps(dict(item), ensure_ascii=False)
self.file.write(v)
self.file.write('\n')
self.file.flush()
return item class FilePipeline(object):
def __init__(self):
if not os.path.exists('imgs'):
os.makedirs('imgs') def process_item(self, item, spider):
response = requests.get(item['url'], stream=True)
file_name = '%s_%s.jpg' % (item['name'], item['school'])
with open(os.path.join('imgs', file_name), mode='wb') as f:
f.write(response.content)
return item
pipelines
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。settings
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('') def close_spider(self,spider):
"""
爬虫关闭时，被调用
:param spider:
:return:
"""
print('')
自定义pipeline
6.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爬虫中间件
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
下载器中间件
7. 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()crawlall.py
- 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
8. 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')
9. 避免重复访问
scrapy默认使用 scrapy.dupefilter.RFPDupeFilter 进行去重，相关配置有：
1 2 3 | 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.seen |
class 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
10.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:[email protected]: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
11.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()
参考版
更多文档参见：http://scrapy-chs.readthedocs.io/zh_CN/latest/index.html
scrapy-redis是一个基于redis的scrapy组件，通过它可以快速实现简单分布式爬虫程序，该组件本质上提供了三大功能：
- scheduler - 调度器
- dupefilter - URL去重规则（被调度器使用）
- pipeline - 数据持久化
scrapy-redis组件
1. URL去重
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 | 定义去重规则（被调度器调用并应用） a. 内部会使用以下配置进行连接Redis # REDIS_HOST = 'localhost' # 主机名 # REDIS_PORT = 6379 # 端口 # REDIS_URL = 'redis://user:pass@hostname:9001' # 连接URL（优先于以上配置） # REDIS_PARAMS = {} # Redis连接参数 默认：REDIS_PARAMS = {'socket_timeout': 30,'socket_connect_timeout': 30,'retry_on_timeout': True,'encoding': REDIS_ENCODING,}） # REDIS_PARAMS['redis_cls'] = 'myproject.RedisClient' # 指定连接Redis的Python模块 默认：redis.StrictRedis # REDIS_ENCODING = "utf-8" # redis编码类型 默认：'utf-8' b. 去重规则通过redis的集合完成，集合的Key为： key = defaults.DUPEFILTER_KEY % {'timestamp': int(time.time())} 默认配置： DUPEFILTER_KEY = 'dupefilter:%(timestamp)s' c. 去重规则中将url转换成唯一标示，然后在redis中检查是否已经在集合中存在 from scrapy.utils import request from scrapy.http import Request req = Request(url='http://www.cnblogs.com/wupeiqi.html') result = request.request_fingerprint(req) print(result) # 8ea4fd67887449313ccc12e5b6b92510cc53675c PS: - URL参数位置不同时，计算结果一致； - 默认请求头不在计算范围，include_headers可以设置指定请求头 示例： from scrapy.utils import request from scrapy.http import Request req = Request(url='http://www.baidu.com?name=8&id=1',callback=lambda x:print(x),cookies={'k1':'vvvvv'}) result = request.request_fingerprint(req,include_headers=['cookies',]) print(result) req = Request(url='http://www.baidu.com?id=1&name=8',callback=lambda x:print(x),cookies={'k1':666}) result = request.request_fingerprint(req,include_headers=['cookies',]) print(result) """# Ensure all spiders share same duplicates filter through redis.# DUPEFILTER_CLASS = "scrapy_redis.dupefilter.RFPDupeFilter" |
2. 调度器
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 | """调度器，调度器使用PriorityQueue（有序集合）、FifoQueue（列表）、LifoQueue（列表）进行保存请求，并且使用RFPDupeFilter对URL去重 a. 调度器 SCHEDULER_QUEUE_CLASS = 'scrapy_redis.queue.PriorityQueue' # 默认使用优先级队列（默认），其他：PriorityQueue（有序集合），FifoQueue（列表）、LifoQueue（列表） SCHEDULER_QUEUE_KEY = '%(spider)s:requests' # 调度器中请求存放在redis中的key SCHEDULER_SERIALIZER = "scrapy_redis.picklecompat" # 对保存到redis中的数据进行序列化，默认使用pickle SCHEDULER_PERSIST = True # 是否在关闭时候保留原来的调度器和去重记录，True=保留，False=清空 SCHEDULER_FLUSH_ON_START = True # 是否在开始之前清空 调度器和去重记录，True=清空，False=不清空 SCHEDULER_IDLE_BEFORE_CLOSE = 10 # 去调度器中获取数据时，如果为空，最多等待时间（最后没数据，未获取到）。 SCHEDULER_DUPEFILTER_KEY = '%(spider)s:dupefilter' # 去重规则，在redis中保存时对应的key SCHEDULER_DUPEFILTER_CLASS = 'scrapy_redis.dupefilter.RFPDupeFilter'# 去重规则对应处理的类"""# Enables scheduling storing requests queue in redis.SCHEDULER = "scrapy_redis.scheduler.Scheduler"# Default requests serializer is pickle, but it can be changed to any module# with loads and dumps functions. Note that pickle is not compatible between# python versions.# Caveat: In python 3.x, the serializer must return strings keys and support# bytes as values. Because of this reason the json or msgpack module will not# work by default. In python 2.x there is no such issue and you can use# 'json' or 'msgpack' as serializers.# SCHEDULER_SERIALIZER = "scrapy_redis.picklecompat"# Don't cleanup redis queues, allows to pause/resume crawls.# SCHEDULER_PERSIST = True# Schedule requests using a priority queue. (default)# SCHEDULER_QUEUE_CLASS = 'scrapy_redis.queue.PriorityQueue'# Alternative queues.# SCHEDULER_QUEUE_CLASS = 'scrapy_redis.queue.FifoQueue'# SCHEDULER_QUEUE_CLASS = 'scrapy_redis.queue.LifoQueue'# Max idle time to prevent the spider from being closed when distributed crawling.# This only works if queue class is SpiderQueue or SpiderStack,# and may also block the same time when your spider start at the first time (because the queue is empty).# SCHEDULER_IDLE_BEFORE_CLOSE = 10 |
3. 数据持久化
1 2 3 4 5 6 7 8 | 2. 定义持久化，爬虫yield Item对象时执行RedisPipeline a. 将item持久化到redis时，指定key和序列化函数 REDIS_ITEMS_KEY = '%(spider)s:items' REDIS_ITEMS_SERIALIZER = 'json.dumps' b. 使用列表保存item数据 |
4. 起始URL相关
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 | """起始URL相关 a. 获取起始URL时，去集合中获取还是去列表中获取？True，集合；False，列表 REDIS_START_URLS_AS_SET = False # 获取起始URL时，如果为True，则使用self.server.spop；如果为False，则使用self.server.lpop b. 编写爬虫时，起始URL从redis的Key中获取 REDIS_START_URLS_KEY = '%(name)s:start_urls' """# If True, it uses redis' ``spop`` operation. This could be useful if you# want to avoid duplicates in your start urls list. In this cases, urls must# be added via ``sadd`` command or you will get a type error from redis.# REDIS_START_URLS_AS_SET = False# Default start urls key for RedisSpider and RedisCrawlSpider.# REDIS_START_URLS_KEY = '%(name)s:start_urls' |
scrapy-redis示例
# DUPEFILTER_CLASS = "scrapy_redis.dupefilter.RFPDupeFilter"
#
#
# from scrapy_redis.scheduler import Scheduler
# from scrapy_redis.queue import PriorityQueue
# SCHEDULER = "scrapy_redis.scheduler.Scheduler"
# SCHEDULER_QUEUE_CLASS = 'scrapy_redis.queue.PriorityQueue' # 默认使用优先级队列（默认），其他：PriorityQueue（有序集合），FifoQueue（列表）、LifoQueue（列表）
# SCHEDULER_QUEUE_KEY = '%(spider)s:requests' # 调度器中请求存放在redis中的key
# SCHEDULER_SERIALIZER = "scrapy_redis.picklecompat" # 对保存到redis中的数据进行序列化，默认使用pickle
# SCHEDULER_PERSIST = True # 是否在关闭时候保留原来的调度器和去重记录，True=保留，False=清空
# SCHEDULER_FLUSH_ON_START = False # 是否在开始之前清空 调度器和去重记录，True=清空，False=不清空
# SCHEDULER_IDLE_BEFORE_CLOSE = 10 # 去调度器中获取数据时，如果为空，最多等待时间（最后没数据，未获取到）。
# SCHEDULER_DUPEFILTER_KEY = '%(spider)s:dupefilter' # 去重规则，在redis中保存时对应的key
# SCHEDULER_DUPEFILTER_CLASS = 'scrapy_redis.dupefilter.RFPDupeFilter'# 去重规则对应处理的类
#
#
#
# REDIS_HOST = '10.211.55.13' # 主机名
# REDIS_PORT = 6379 # 端口
# # REDIS_URL = 'redis://user:pass@hostname:9001' # 连接URL（优先于以上配置）
# # REDIS_PARAMS = {} # Redis连接参数 默认：REDIS_PARAMS = {'socket_timeout': 30,'socket_connect_timeout': 30,'retry_on_timeout': True,'encoding': REDIS_ENCODING,}）
# # REDIS_PARAMS['redis_cls'] = 'myproject.RedisClient' # 指定连接Redis的Python模块 默认：redis.StrictRedis
# REDIS_ENCODING = "utf-8" # redis编码类型 默认：'utf-8'
配置文件
import scrapy class ChoutiSpider(scrapy.Spider):
name = "chouti"
allowed_domains = ["chouti.com"]
start_urls = (
'http://www.chouti.com/',
) def parse(self, response):
for i in range(0,10):
yield
爬虫文件