Scrapy框架
Scrapy
Scrapy是一个为了爬取网站数据，提取结构性数据而编写的应用框架。 其可以应用在数据挖掘，信息处理或存储历史数据等一系列的程序中。
Scrapy囊括了爬取网站数据几乎所有的功能,是一个扩展性很强的一个框架,Scrapy在爬虫界里相当于web的Django
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。 -
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 下载器中间件
- 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。 -
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 爬虫中间件
- 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
-
Scrapy的安装
Windows
a. pip3 install wheel（使pip能够安装.whl文件）
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/
Linux
pip install scrapy
1、基本命令
scrapy startproject xdb 创建项目
cd xdb
scrapy genspider chouti chouti.com 创建爬虫
scrapy crawl chouti --nolog 启动爬虫
2、爬虫目录结构
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
爬取抽屉的新闻链接
spider
# -*- coding: utf-8 -*-
import scrapy
from scrapy.http import Request
from ..items import FirstspiderItem
class ChoutiSpider(scrapy.Spider):
name = 'chouti'
allowed_domains = ['chouti.com']
start_urls = ['http://chouti.com/']
def parse(self, response):
# print('response.request.url',response.request.url)
# print(response,type(response)) # 对象
# print(response.text.strip())
"""
from bs4 import BeautifulSoup
soup = BeautifulSoup(response.text,'html.parser')
content_list = soup.find('div',attrs={'id':'content-list'})
"""
# 去子孙中找div并且id=content-list
# f = open('news.log', mode='a+')
item_list = response.xpath('//div[@id="content-list"]/div[@class="item"]')
for item in item_list:
text = item.xpath('.//a/text()').extract_first()
href = item.xpath('.//a/@href').extract_first()
# f.write(href+'\n')
yield FirstspiderItem(href=href)
# f.close()
page_list = response.xpath('//div[@id="dig_lcpage"]//a/@href').extract()
for page in page_list:
url_1 = "https://dig.chouti.com" + page
yield Request(url=url_1,callback=self.parse,) # https://dig.chouti.com/all/hot/recent/2
items
import scrapy
class FirstspiderItem(scrapy.Item):
# define the fields for your item here like:
href = scrapy.Field()
pipelines
class FirstspiderPipeline(object):
def __init__(self,path):
self.f = None
self.path = path
@classmethod
def from_crawler(cls,crawler):
path = crawler.settings.get('HREF_FILE_PATH')
return cls(path)
# print('File.from_crawler')
# path = crawler.settings.get('HREF_FILE_PATH')
# return cls(path)
def open_spider(self,spider):
print('开始爬虫')
self.f =open(self.path, mode='a+')
def process_item(self, item, spider):
print(item['href'])
self.f.write(item['href']+'\n')
return item
def close_spider(self,spider):
print('结束爬虫')
self.f.close()
# -*- coding: utf-8 -*- # Define your item pipelines here # # Don't forget to add your pipeline to the ITEM_PIPELINES setting # See: https://doc.scrapy.org/en/latest/topics/item-pipeline.html """ """ """ 源码内容： 1. 判断当前XdbPipeline类中是否有from_crawler 有： obj = XdbPipeline.from_crawler(....) 否： obj = XdbPipeline() 2. obj.open_spider() 3. obj.process_item()/obj.process_item()/obj.process_item()/obj.process_item()/obj.process_item() 4. obj.close_spider() """ from scrapy.exceptions import DropItem class FilePipeline(object): def __init__(self,path): self.f = None self.path = path @classmethod def from_crawler(cls, crawler): """ 初始化时候，用于创建pipeline对象 :param crawler: :return: """ print('File.from_crawler') path = crawler.settings.get('HREF_FILE_PATH') return cls(path) def open_spider(self,spider): """ 爬虫开始执行时，调用 :param spider: :return: """ # if spider.name == 'chouti': print('File.open_spider') self.f = open(self.path,'a+') def process_item(self, item, spider): # f = open('xx.log','a+') # f.write(item['href']+'\n') # f.close() print('File',item['href']) self.f.write(item['href']+'\n') # return item raise DropItem() def close_spider(self,spider): """ 爬虫关闭时，被调用 :param spider: :return: """ print('File.close_spider') self.f.close() class DbPipeline(object): def __init__(self,path): self.f = None self.path = path @classmethod def from_crawler(cls, crawler): """ 初始化时候，用于创建pipeline对象 :param crawler: :return: """ print('DB.from_crawler') path = crawler.settings.get('HREF_DB_PATH') return cls(path) def open_spider(self,spider): """ 爬虫开始执行时，调用 :param spider: :return: """ print('Db.open_spider') self.f = open(self.path,'a+') def process_item(self, item, spider): # f = open('xx.log','a+') # f.write(item['href']+'\n') # f.close() print('Db',item) # self.f.write(item['href']+'\n') return item def close_spider(self,spider): """ 爬虫关闭时，被调用 :param spider: :return: """ print('Db.close_spider') self.f.close()
settings中引擎配置
ROBOTSTXT_OBEY = False
USER_AGENT = 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/69.0.3497.100 Safari/537.36'
pipelines在settings的配置
ITEM_PIPELINES={
'Firstspider.pipelines.FirstspiderPipeline': 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。
HREF_FILE_PATH='new.log'
关于window编码
import sys,os
sys.stdout=io.TextIOWrapper(sys.stdout.buffer,encoding='gb18030')
抽屉爬虫点赞
cookie的使用
yield Request(url=url, callback=self.login, meta={'cookiejar': True})
#-*- coding: utf-8 -*-
import os,io,sys
sys.stdout=io.TextIOWrapper(sys.stdout.buffer,encoding='gb18030')
import scrapy
from scrapy.http import Request
from scrapy.http.cookies import CookieJar
class ChoutizanSpider(scrapy.Spider):
name = 'choutizan'
# allowed_domains = ['chouti.com']
start_urls = ['http://chouti.com/']
cookie_dict = {}
def parse(self, response):
print('parse开始')
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
yield Request(url='http://chouti.com/',callback=self.login)
def login(self,response):
print('qwert')
yield Request(
url='https://dig.chouti.com/login',
method='POST',
headers={
'Content-Type':'application/x-www-form-urlencoded; charset=UTF-8'
},
cookies=self.cookie_dict,
body="phone=8615339953615&password=w11111111&oneMonth=1",
callback=self.check_login
)
def check_login(self,response):
print(response.text)
yield Request(
url='https://dig.chouti.com/all/hot/recent/1',
cookies=self.cookie_dict,
callback=self.dianzan
)
def dianzan(self,response):
print('执行dianzan')
response_list = response.xpath('//div[@id="content-list"]/div[@class="item"]/div[@class="news-content"]/div[@class="part2"]/@share-linkid').extract()
# for new in response_list:
# new.xpath('/')
# print(response_list)
for new in response_list:
url1 ='https://dig.chouti.com/link/vote?linksId='+new
print(url1)
yield Request(
url=url1,
method='POST',
cookies=self.cookie_dict,
callback=self.check_dianzan
)
url_list = response.xpath('//div[@id="dig_lcpage"]//a/@href').extract()
for url_1 in url_list:
page = 'https://dig.chouti.com'+url_1
yield Request(
url=page,
callback=self.dianzan
)
def check_dianzan(self,response):
print(response.text)
# page_list = response.xpath('//div[@id="dig_lcpage"]//a/@href').extract()
# for page in page_list:
#
# url_1 = "https://dig.chouti.com" + page
# print(url_1)
# yield Request(url=url_1,callback=self.dianzan,) # https://dig.chouti.com/all/hot/recent/2
爬虫去重控制
dupefilters.py 中request_seen编写正确的逻辑，dont_filter=False
from scrapy.dupefilter import BaseDupeFilter
from scrapy.utils.request import request_fingerprint
class XdbDupeFilter(BaseDupeFilter):
def __init__(self):
self.visited_fd = set()
@classmethod
def from_settings(cls, settings):
return cls()
def request_seen(self, request):
fd = request_fingerprint(request=request)
if fd in self.visited_fd:
return True
self.visited_fd.add(fd)
def open(self): # can return deferred
print('开始')
def close(self, reason): # can return a deferred
print('结束')
# def log(self, request, spider): # log that a request has been filtered
# print('日志')
dupefilters.py的settings中：
# 修改默认的去重规则 # DUPEFILTER_CLASS = 'scrapy.dupefilter.RFPDupeFilter' DUPEFILTER_CLASS = 'xdb.dupefilters.XdbDupeFilter'
配置文件中限制深度
# 限制深度 DEPTH_LIMIT = 3
取url的深度：print(response.request.url, response.meta.get('depth',0))
scrapy解析器
from scrapy.http import HtmlResponse
from scrapy.selector import Selector
response = HtmlResponse(url='http://example.com', body=html,encoding='utf-8')
# hxs = Selector(response)
# hxs.xpath()
response.xpath('')
起始请求定制 start_requests
内置代理
自定义代理 proxy.py中
# by luffycity.com
import base64
import random
from six.moves.urllib.parse import unquote
try:
from urllib2 import _parse_proxy
except ImportError:
from urllib.request import _parse_proxy
from six.moves.urllib.parse import urlunparse
from scrapy.utils.python import to_bytes
class XdbProxyMiddleware(object):
def _basic_auth_header(self, username, password):
user_pass = to_bytes(
'%s:%s' % (unquote(username), unquote(password)),
encoding='latin-1')
return base64.b64encode(user_pass).strip()
def process_request(self, request, spider):
PROXIES = [
"http://root:woshiniba@192.168.11.11:9999/",
"http://root:woshiniba@192.168.11.12:9999/",
"http://root:woshiniba@192.168.11.13:9999/",
"http://root:woshiniba@192.168.11.14:9999/",
"http://root:woshiniba@192.168.11.15:9999/",
"http://root:woshiniba@192.168.11.16:9999/",
]
url = random.choice(PROXIES)
orig_type = ""
proxy_type, user, password, hostport = _parse_proxy(url)
proxy_url = urlunparse((proxy_type or orig_type, hostport, '', '', '', ''))
if user:
creds = self._basic_auth_header(user, password)
else:
creds = None
request.meta['proxy'] = proxy_url
if creds:
request.headers['Proxy-Authorization'] = b'Basic ' + creds
class DdbProxyMiddleware(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.b64encode(to_bytes(proxy['user_pass']))
request.headers['Proxy-Authorization'] = to_bytes('Basic ' + encoded_user_pass)
else:
request.meta['proxy'] = to_bytes("http://%s" % proxy['ip_port'])
settings的配置
DOWNLOADER_MIDDLEWARES = {
#'xdb.middlewares.XdbDownloaderMiddleware': 543,
'xdb.proxy.XdbProxyMiddleware':751,
}
自定制命令
单个爬虫
import sys
from scrapy.cmdline import execute
if __name__ == '__main__':
execute(["scrapy","crawl",“chouti”，"--nolog"])
多个爬虫
- 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
爬虫信号
# by luffycity.com
from scrapy import signals
class MyExtend(object):
def __init__(self):
pass
@classmethod
def from_crawler(cls, crawler):
self = cls()
crawler.signals.connect(self.x1, signal=signals.spider_opened)
crawler.signals.connect(self.x2, signal=signals.spider_closed)
return self
def x1(self, spider):
print('open')
def x2(self, spider):
print('close')
信号中settings的配置
EXTENSIONS = {
# 'scrapy.extensions.telnet.TelnetConsole': None,
'xdb.ext.MyExtend':666,
}
爬虫基于scrapy-redis的去重
settings的配置
# ############### scrapy redis连接 ####################
REDIS_HOST = '140.143.227.206' # 主机名
REDIS_PORT = 8888 # 端口
REDIS_PARAMS = {'password':'beta'} # Redis连接参数 默认：REDIS_PARAMS = {'socket_timeout': 30,'socket_connect_timeout': 30,'retry_on_timeout': True,'encoding': REDIS_ENCODING,}）
REDIS_ENCODING = "utf-8" # redis编码类型 默认：'utf-8'
# REDIS_URL = 'redis://user:pass@hostname:9001' # 连接URL（优先于以上配置）
# ############### scrapy redis去重 ####################
DUPEFILTER_KEY = 'dupefilter:%(timestamp)s'
# DUPEFILTER_CLASS = 'scrapy_redis.dupefilter.RFPDupeFilter'
DUPEFILTER_CLASS = 'dbd.xxx.RedisDupeFilter'
from scrapy.dupefilter import BaseDupeFilter
import redis
from scrapy.utils.request import request_fingerprint
import scrapy_redis
class DupFilter(BaseDupeFilter):
def __init__(self):
self.conn = redis.Redis(host='140.143.227.206',port=8888,password='beta')
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
"""
fid = request_fingerprint(request)
result = self.conn.sadd('visited_urls', fid)
if result == 1:
return False
return True
###############以上为完全自定义的去重########################
###############以下为继承scrapy-redis的去重########################
from scrapy_redis.dupefilter import RFPDupeFilter
from scrapy_redis.connection import get_redis_from_settings
from scrapy_redis import defaults
class RedisDupeFilter(RFPDupeFilter):
@classmethod
def from_settings(cls, settings):
"""Returns an instance from given settings.
This uses by default the key ``dupefilter:<timestamp>``. When using the
``scrapy_redis.scheduler.Scheduler`` class, this method is not used as
it needs to pass the spider name in the key.
Parameters
----------
settings : scrapy.settings.Settings
Returns
-------
RFPDupeFilter
A RFPDupeFilter instance.
"""
server = get_redis_from_settings(settings)
# XXX: This creates one-time key. needed to support to use this
# class as standalone dupefilter with scrapy's default scheduler
# if scrapy passes spider on open() method this wouldn't be needed
# TODO: Use SCRAPY_JOB env as default and fallback to timestamp.
key = defaults.DUPEFILTER_KEY % {'timestamp': 'xiaodongbei'}
debug = settings.getbool('DUPEFILTER_DEBUG')
return cls(server, key=key, debug=debug)
I can feel you forgetting me。。 有一种默契叫做我不理你,你就不理我
