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Python3學習urllib的使用方法示例

更新時間：2017年11月29日 10:45:46 作者：Data&Truth

本篇文章主要介紹了Python3學習urllib的使用方法示例，小編覺得挺不錯的，現(xiàn)在分享給大家，也給大家做個參考。一起跟隨小編過來看看吧

urllib是python的一個獲取url(Uniform Resource Locators,統(tǒng)一資源定址符)了，可以利用它來抓取遠程的數(shù)據(jù)進行保存，本文整理了一些關(guān)于urllib使用中的一些關(guān)于header,代理,超時,認證,異常處理處理方法。

1.基本方法

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

url: 需要打開的網(wǎng)址
data：Post提交的數(shù)據(jù)
timeout：設(shè)置網(wǎng)站的訪問超時時間

直接用urllib.request模塊的urlopen（）獲取頁面，page的數(shù)據(jù)格式為bytes類型，需要decode（）解碼，轉(zhuǎn)換成str類型。

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

urlopen返回對象提供方法：

read() , readline() ,readlines() , fileno() , close() ：對HTTPResponse類型數(shù)據(jù)進行操作
info()：返回HTTPMessage對象，表示遠程服務(wù)器返回的頭信息
getcode()：返回Http狀態(tài)碼。如果是http請求，200請求成功完成;404網(wǎng)址未找到
geturl()：返回請求的url

1、簡單讀取網(wǎng)頁信息

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（）來包裝請求，再通過urlopen（）獲取頁面。

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

3、發(fā)送數(shù)據(jù)，以登錄知乎為例

''''' 
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("嘗試解壓縮...") 
    data = gzip.decompress(data) 
    print("解壓完畢") 
  except: 
    print("未經(jīng)壓縮，無需解壓") 
   
  return data 
     
def getXSRF(data): 
  cer = re.compile('name=\"_xsrf\" value=\"(.*)\"',flags = 0) 
  strlist = cer.findall(data) 
  return strlist[0] 
 
def getOpener(head): 
  # cookies 處理 
  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信息可以通過firebug獲得 
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 = "登錄賬號" 
password = "登錄密碼" 
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錯誤

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、異常處理

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認證

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 = "http://www.dbjr.com.cn /" 
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 = "http://www.dbjr.com.cn /" 
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、超時

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('http://www.dbjr.com.cn /') 
a = urllib.request.urlopen(req).read() 
print(a)

以上就是本文的全部內(nèi)容，希望對大家的學習有所幫助，也希望大家多多支持腳本之家。

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