Python3学习urllib的使用方法示例

Python  /  管理员 发布于 7年前   176

urllib是python的一个获取url(Uniform Resource Locators,统一资源定址符)了，可以利用它来抓取远程的数据进行保存，本文整理了一些关于urllib使用中的一些关于header,代理,超时,认证,异常处理处理方法。

1.基本方法

urllib.request.urlopen(url, data=None, [timeout, ]*, cafile=None, capath=None, cadefault=False, context=None)

1. url:  需要打开的网址
2. data：Post提交的数据
3. timeout：设置网站的访问超时时间

直接用urllib.request模块的urlopen（）获取页面，page的数据格式为bytes类型，需要decode（）解码，转换成str类型。

from urllib import requestresponse = request.urlopen(r'http://python.org/') # <http.client.HTTPResponse object at 0x00000000048BC908> HTTPResponse类型page = response.read()page = page.decode('utf-8')

urlopen返回对象提供方法：

1. read() , readline() ,readlines() , fileno() , close() ：对HTTPResponse类型数据进行操作
2. info()：返回HTTPMessage对象，表示远程服务器返回的头信息
3. getcode()：返回Http状态码。如果是http请求，200请求成功完成;404网址未找到
4. geturl()：返回请求的url

1、简单读取网页信息

import urllib.request response = urllib.request.urlopen('http://python.org/') html = response.read() 

2、使用request

urllib.request.Request(url, data=None, headers={}, method=None)

使用request（）来包装请求，再通过urlopen（）获取页面。

import urllib.request req = urllib.request.Request('http://python.org/') response = urllib.request.urlopen(req) the_page = response.read() 

3、发送数据，以登录知乎为例

''''' Created on 2016年5月31日  @author: gionee ''' import gzip import re import urllib.request import urllib.parse import http.cookiejar  def ungzip(data):   try:     print("尝试解压缩...")     data = gzip.decompress(data)     print("解压完毕")   except:     print("未经压缩，无需解压")      return data      def getXSRF(data):   cer = re.compile('name=\"_xsrf\" value=\"(.*)\"',flags = 0)   strlist = cer.findall(data)   return strlist[0]  def getOpener(head):   # cookies 处理   cj = http.cookiejar.CookieJar()   pro = urllib.request.HTTPCookieProcessor(cj)   opener = urllib.request.build_opener(pro)   header = []   for key,value in head.items():     elem = (key,value)     header.append(elem)   opener.addheaders = header   return opener # header信息可以通过firebug获得 header = {   'Connection': 'Keep-Alive',   'Accept': 'text/html, application/xhtml+xml, */*',   'Accept-Language': 'en-US,en;q=0.8,zh-Hans-CN;q=0.5,zh-Hans;q=0.3',   'User-Agent': 'Mozilla/5.0 (Windows NT 6.1; WOW64; rv:46.0) Gecko/20100101 Firefox/46.0',   'Accept-Encoding': 'gzip, deflate',   'Host': 'www.zhihu.com',   'DNT': '1' }  url = 'http://www.zhihu.com/' opener = getOpener(header) op = opener.open(url) data = op.read() data = ungzip(data) _xsrf = getXSRF(data.decode())  url += "login/email" email = "登录账号" password = "登录密码" postDict = {   '_xsrf': _xsrf,   'email': email,   'password': password,   'rememberme': 'y'  } postData = urllib.parse.urlencode(postDict).encode() op = opener.open(url,postData) data = op.read() data = ungzip(data)  print(data.decode()) 

4、http错误

import urllib.request req = urllib.request.Request('http://www.lz881228.blog.163.com ') try:   urllib.request.urlopen(req) except urllib.error.HTTPError as e: print(e.code) print(e.read().decode("utf8")) 

5、异常处理

from urllib.request import Request, urlopen from urllib.error import URLError, HTTPError  req = Request("http://www.abc.com /") try:   response = urlopen(req) except HTTPError as e:   print('The server couldn't fulfill the request.')   print('Error code: ', e.code) except URLError as e:   print('We failed to reach a server.')   print('Reason: ', e.reason) else:   print("good!")   print(response.read().decode("utf8")) 

6、http认证

import urllib.request  # create a password manager password_mgr = urllib.request.HTTPPasswordMgrWithDefaultRealm()  # Add the username and password. # If we knew the realm, we could use it instead of None. top_level_url = "https:// /" password_mgr.add_password(None, top_level_url, 'rekfan', 'xxxxxx')  handler = urllib.request.HTTPBasicAuthHandler(password_mgr)  # create "opener" (OpenerDirector instance) opener = urllib.request.build_opener(handler)  # use the opener to fetch a URL a_url = "https:// /" x = opener.open(a_url) print(x.read())  # Install the opener. # Now all calls to urllib.request.urlopen use our opener. urllib.request.install_opener(opener) a = urllib.request.urlopen(a_url).read().decode('utf8')  print(a) 

7、使用代理

import urllib.request  proxy_support = urllib.request.ProxyHandler({'sock5': 'localhost:1080'}) opener = urllib.request.build_opener(proxy_support) urllib.request.install_opener(opener)  a = urllib.request.urlopen("http://www.baidu.com ").read().decode("utf8") print(a) 

8、超时

import socket import urllib.request  # timeout in seconds timeout = 2 socket.setdefaulttimeout(timeout)  # this call to urllib.request.urlopen now uses the default timeout # we have set in the socket module req = urllib.request.Request('// /') a = urllib.request.urlopen(req).read() print(a) 

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。