基本模块
python爬虫，web spider。爬取网站获取网页数据，并进行分析提取。
基本模块使用的是 urllib，urllib2，re，等模块
基本用法，例子：
（1）进行基本GET请求，获取网页html
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#!coding=utf-8import urllibimport urllib2 url = 'http://www.baidu.com/'# 获取请求request = urllib2.Request(url)try: # 根据request，得到返回response response = urllib2.urlopen(request)except urllib2.HTTPError, e: if hasattr(e, 'reason'): print e.reason# 读取response的bodyhtml = response.read()# 读取response的headersheaders = response.info() |
（2）表单提交
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#!coding=utf-8import urllib2import urllib post_url = '' post_data = urllib.urlencode({ 'username': 'username', 'password': 'password',}) post_headers = { 'User-Agent': 'Mozilla/5.0 (X11; Ubuntu; Linux i686; rv:31.0) Gecko/20100101 Firefox/31.0',} request = urllib2.Request( url=post_url, data=post_data, headers=post_headers,) response = urllib2.urlopen(request) html = response.read() |
(3)
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#!coding=utf-8 import urllib2import re page_num = 1url = 'http://tieba.baidu.com/p/3238280985?see_lz=1&pn='+str(page_num)myPage = urllib2.urlopen(url).read().decode('gbk') myRe = re.compile(r'class="d_post_content j_d_post_content ">(.*?)</div>', re.DOTALL)items = myRe.findall(myPage) f = open('baidu.txt', 'a+') import sysreload(sys)sys.setdefaultencoding('utf-8') i = 0texts = []for item in items: i += 1 print i text = item.replace('<br>', '') text.replace('\n', '').replace(' ', '') + '\n' print text f.write(text) f.close() |
(4)
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#coding:utf-8''' 模拟登陆163邮箱并下载邮件内容 '''import urllibimport urllib2import cookielibimport reimport timeimport json class Email163: header = {'User-Agent':'Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.1.6) Gecko/20091201 Firefox/3.5.6'} user = '' cookie = None sid = None mailBaseUrl='http://twebmail.mail.163.com' def __init__(self): self.cookie = cookielib.CookieJar() cookiePro = urllib2.HTTPCookieProcessor(self.cookie) urllib2.install_opener(urllib2.build_opener(cookiePro)) def login(self,user,pwd): ''' 登录 ''' postdata = urllib.urlencode({ 'username':user, 'password':pwd, 'type':1 }) #注意版本不同，登录URL也不同 req = urllib2.Request( url='https://ssl.mail.163.com/entry/coremail/fcg/ntesdoor2?funcid=loginone&language=-1&passtype=1&iframe=1&product=mail163&from=web&df=email163&race=-2_45_-2_hz&module=&uid='+user+'&style=10&net=t&skinid=null', data=postdata, headers=self.header, ) res = str(urllib2.urlopen(req).read()) #print res patt = re.compile('sid=([^"]+)',re.I) patt = patt.search(res) uname = user.split('@')[0] self.user = user if patt: self.sid = patt.group(1).strip() #print self.sid print '%s Login Successful.....'%(uname) else: print '%s Login failed....'%(uname) def getInBox(self): ''' 获取邮箱列表 ''' print '\nGet mail lists.....\n' sid = self.sid url = self.mailBaseUrl+'/jy3/list/list.do?sid='+sid+'&fid=1&fr=folder' res = urllib2.urlopen(url).read() #获取邮件列表 mailList = [] patt = re.compile('<div\s+class="tdLike Ibx_Td_From"[^>]+>.*?href="([^"]+)"[^>]+>(.*?)<\/a>.*?<div\s+class="tdLike Ibx_Td_Subject"[^>]+>.*?href="[^>]+>(.*?)<\/a>',re.I|re.S) patt = patt.findall(res) if patt==None: return mailList for i in patt: line = { 'from':i[1].decode('utf8'), 'url':self.mailBaseUrl+i[0], 'subject':i[2].decode('utf8') } mailList.append(line) return mailList def getMailMsg(self,url): ''' 下载邮件内容 ''' content='' print '\n Download.....%s\n'%(url) res = urllib2.urlopen(url).read() patt = re.compile('contentURL:"([^"]+)"',re.I) patt = patt.search(res) if patt==None: return content url = '%s%s'%(self.mailBaseUrl,patt.group(1)) time.sleep(1) res = urllib2.urlopen(url).read() Djson = json.JSONDecoder(encoding='utf8') jsonRes = Djson.decode(res) if 'resultVar' in jsonRes: content = Djson.decode(res)['resultVar'] time.sleep(3) return content ''' Demon'''#初始化mail163 = Email163()#登录mail163.login('lpe234@163.com','944898186')time.sleep(2) #获取收件箱elist = mail163.getInBox() #获取邮件内容for i in elist: print '主题：%s 来自：%s 内容：\n%s'%(i['subject'].encode('utf8'),i['from'].encode('utf8'),mail163.getMailMsg(i['url']).encode('utf8')) |
（５）需要登陆的情况
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#1 cookie的处理 import urllib2, cookielibcookie_support= urllib2.HTTPCookieProcessor(cookielib.CookieJar())opener = urllib2.build_opener(cookie_support, urllib2.HTTPHandler)urllib2.install_opener(opener)content = urllib2.urlopen('http://XXXX').read() #2 用代理和cookie opener = urllib2.build_opener(proxy_support, cookie_support, urllib2.HTTPHandler) #3 表单的处理 import urllibpostdata=urllib.urlencode({ 'username':'XXXXX', 'password':'XXXXX', 'continueURI':'http://www.verycd.com/', 'fk':fk, 'login_submit':'登录'}) req = urllib2.Request( url = 'http://secure.verycd.com/signin/*/http://www.verycd.com/', data = postdata)result = urllib2.urlopen(req).read() #4 伪装成浏览器访问 headers = { 'User-Agent':'Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.1.6) Gecko/20091201 Firefox/3.5.6'}req = urllib2.Request( url = 'http://secure.verycd.com/signin/*/http://www.verycd.com/', data = postdata, headers = headers) #5 反”反盗链” headers = { 'Referer':'http://www.cnbeta.com/articles'} |
（６）多线程
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from threading import Threadfrom Queue import Queuefrom time import sleep#q是任务队列#NUM是并发线程总数#JOBS是有多少任务q = Queue()NUM = 2JOBS = 10#具体的处理函数，负责处理单个任务def do_somthing_using(arguments): print arguments#这个是工作进程，负责不断从队列取数据并处理def working(): while True: arguments = q.get() do_somthing_using(arguments) sleep(1) q.task_done()#fork NUM个线程等待队列for i in range(NUM): t = Thread(target=working) t.setDaemon(True) t.start()#把JOBS排入队列for i in range(JOBS): q.put(i)#等待所有JOBS完成q.join() |
scrapy框架
Scrapy框架，Python开发的一个快速,高层次的屏幕抓取和web抓取框架，用于抓取web站点并从页面中提取结构化的数据。Scrapy用途广泛，可以用于数据挖掘、监测和自动化测试。
刚开始学习这个框架。不太好评论。只是感觉这个框架有些Java的感觉，需要太多的其他模块的支持。
（一）创建 scrapy 项目
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# 使用 scrapy startproject scrapy_test├── scrapy_test│ ├── scrapy.cfg│ └── scrapy_test│ ├── __init__.py│ ├── items.py│ ├── pipelines.py│ ├── settings.py│ └── spiders│ ├── __init__.py# 进行创建 scrapy 项目 |
（二）说明
scrapy.cfg: 项目配置文件
items.py: 需要提取的数据结构定义文件
pipelines.py:管道定义，用来对items里面提取的数据做进一步处理，如保存等
settings.py: 爬虫配置文件
spiders: 放置spider的目录
（三）依赖包
依赖包比较麻烦。
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# python-dev 包的安装apt-get install python-dev # twisted, w3lib, six, queuelib, cssselect， libxslt pip install w3libpip install twistedpip install lxmlapt-get install libxml2-dev libxslt-dev apt-get install python-lxmlpip install cssselect pip install pyOpenSSL sudo pip install service_identity # 安装好之后，便可使用 scrapy startproject test 进行创建项目 |
（四）抓取实例。
（1）创建scrapy项目
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dizzy@dizzy-pc:~/Python/spit$ scrapy startproject itzhaopinNew Scrapy project 'itzhaopin' created in: /home/dizzy/Python/spit/itzhaopin You can start your first spider with: cd itzhaopin scrapy genspider example example.comdizzy@dizzy-pc:~/Python/spit$ dizzy@dizzy-pc:~/Python/spit$ cd itzhaopindizzy@dizzy-pc:~/Python/spit/itzhaopin$ tree.├── itzhaopin│ ├── __init__.py│ ├── items.py│ ├── pipelines.py│ ├── settings.py│ └── spiders│ └── __init__.py└── scrapy.cfg # scrapy.cfg: 项http://my.oschina.net/lpe234/admin/new-blog目配置文件# items.py: 需要提取的数据结构定义文件# pipelines.py:管道定义，用来对items里面提取的数据做进一步处理，如保存等# settings.py: 爬虫配置文件# spiders: 放置spider的目录 |
（2）定义要抓取的数据结构 items.py
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from scrapy.item import Item, Field# 定义我们要抓取的数据class TencentItem(Item): name = Field() # 职位名称 catalog = Field() # 职位类别 workLocation = Field() # 工作地点 recruitNumber = Field() # 招聘人数 detailLink = Field() # 职位详情链接 publishTime = Field() # 发布时间 |
(3)实现Spider类
- Spider是继承自 scarpy.contrib.spiders.CrawlSpider 的Python类，有3个必须定义的成员。
- name : 名称，spider的标识。
- start_urls : 一个url列表，spider从这些网页开始抓取
- parse() : 一个方法。当start_urls里面的网页抓取下来之后需要调用这个方法来解析网页内容，同时需要返回下一个需要抓取的网页，或者返回items列表。
在spiders目录下面新建一个spider，tencent_spider.py ：
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#coding=utf-8 from scrapy.spider import BaseSpider class DmozSpider(BaseSpider): name = 'dmoz' allowed_domains = ['dmoz.org'] start_urls = [ 'http://www.dmoz.org/Computers/Programming/Languages/Python/Books/', 'http://www.dmoz.org/Computers/Programming/Languages/Python/Resources/' ] def parse(self, response): filename = response.url.split('/')[-2] open(filename, 'wb').write(response.info) |
这个简单一些。 使用scrapy crawl dmoz # 即可运行spider
