了解即可,不好用
一. 概述
python内置的http请求库,包括4个模块,分别如下
urllib.request 请求模块
urllib.error 异常处理模块
urllib.parse url解析模块, 工具模块
urllib.robotparser robots.txt解析模块
urlopen
python2和python3中urlopen方法的不同用法
python2中
import urllib2
response=urllib2.urlopen('http://www.baidu.com')
python3中
import urllib.request
response=urllib.request.urlopen('http://www.baidu.com')
二. urlopen用法
1. 获取普通源代码,get方法
import urllib.request response=urllib.request.urlopen('http://www.baidu.com') print(response.read().decode('utf-8')
2. post方法请求,传入一个字典
import urllib.parse import urllib.request data=bytes(urllib.parse.urlencode({'word':'hello'}), encoding='utf8') //传入一个值 response=urllib.request.urlopen('http://httpbin.org/post', data=data) print(response.read())
3. 超时操作,在指定时间内未得到响应就抛出异常
import urllib.request response = urllib.request.urlopen('http://httpbin.org/get', timeout=1) print(response.read())
4. 查看异常
import socket import urllib.request import urllib.error try: response = urllib.request.urlopen('http://httpbin.org/get', timeout=0.1) except urllib.error.URLError as e: if isinstance(e.reason, socket.timeout): print('TIME OUT')
三. 响应
1. 响应类型
import urllib.request response = urllib.request.urlopen('https://www.python.org') print(type(response))
2. 状态码,响应头
import urllib.request response = urllib.request.urlopen('https://www.python.org') print(response.status) print(response.getheaders()) //数组的形式,每个数组元素都是一个元组 print(response.getheader('Server')) //获取数组元素中元组键名为Server的值
3. Request()方法单独使用来请求页面
import urllib.request request = urllib.request.Request('https://python.org') response = urllib.request.urlopen(request) print(response.read().decode('utf-8'))
可以在请求中加入头信息等数据
from urllib import request,parse url = 'http://httpbin.org/post' headers = { 'User-Agent': 'Mozilla/4.0(compatible; MSIE 5.5; Windows NT)', 'Host': 'httpbin.org' } dict = { 'name': 'Germey' } data = bytes(parse.urlencode(dict), encoding='utf8') req = request.Requests(url=url, data=data, headers=headers, method='POST') response = request.urlopen(req) print(response.read().decode('utf-8'))
使用add_header()方法来添加header
from urllib import request, parse url = 'http://httpdbin.org/post' dict = { 'name': 'Germey' } data = bytes(parse.urlencode(dict), encoding='utf8') req = request.Requests(url=url, data=data, method='POST') req.add_header('User-Agent', 'Mozilla/4.0(compatible; MSIE 5.5; Windows NT)') response = request.urlopen(req) print(response.read().decode('utf-8'))
4. Handler
1. 代理
import urllib.request proxy_handler = urllib.request.ProxyHander({ 'http':'http://127.0.0.1:9743' 'https':'https://127.0.0.1:9743' }) opener = urllib.requets.build_opener(proxy_handler) response = opener.open('http://www.baidu.com') print(response.read())
2. Cookie
例子1,打印出cookie信息
import http.cookiejar,urlib.request cookie = http.cookiejar.CookieJar() handler = urllib.request.HTTPCookieProcessor(cookie) opener = urllib.request.build_opener(handler) response = opener.open('http://www.baidu.com') for item in cookie: print(item.name+"="+item.value)
例子2,保存cookie信息到文本文件
import http.cookiejar, urllib.requst filename = 'cookie.txt' cookie = http.cookiejar.MozillaCookieJar(filename) handler = urllib.request.HTTPCookieProcessor(cookie) opener = urllib.requst.build_opener(handler) response = opener.open('http://www.baidu.com') cookie.save(ignore_discard=True, ignore_expires=True)
例子3,另外一种保存方法
import http.cookiejar, urllib.request filename = 'cookie.txt' cookie = http.cookiejar.LWPCookieJar(filename) handler = urllib.request.HTTPCookieProcessor(cookie) opener = urllib.request.build_opener(hander) response = opener.open('http://www.baidu.com') cookie.save(ignore_discard=True, ignore_expires=True)
例子4,读取cookie文件
import http.cookiejar, urllib.request cookie = http.cookiejar.LWPCookieJar() cookie.load('cookie.txt', ignore_discard=True, ignore_expires=True) handler = urllib.request.HTTPCookieProcessor(cookie) opener = urllib.request.build_opener(handler) response = opener.open('http://www.baidu.com') print(response.read().decode('utf-8'))
5. 异常处理
一般可捕获3个异常类型,分别为URLError, HTTPError, ContentTooShortError
1. 打印异常原因, URLError:只有一个reason属性
from urllib import request, error try: response = request.urlopen('http://cuiqingcai.com/index.html') except error.URLError as e: print(e.reason)
2. HTTPError是URLError的子类,有三个属性:code,reason,headers
from urllib import request, error try: response = request.urlopen('http://cuiqingcai.com/index.htm') except error.HTTPError as e: print(e.reason, e.code, e.headers, sep=' ') except error,URLError as e: print(e.reason) else: print('Request Successfully')
3. 验证异常原因
import socket import urllib.request import urllib.error try: response = urllib.request.urlopen('https://www.baidu.com',timeout=0.01) except urllib.error.URLError as e: print(type(e.reason)) if isinstance(e.reason, socket.timeout): print('TIME OUT')
六. URL解析
urlparse模块
语法:urllib.parse.urlparse(urlstring, scheme='', allow_fragments=True)
1. 拆分URL并分段获取URL地址
from urllib.parse import urlparse result = urlparse('http://www.baidu.com/index.html;user?id=5#comment') print(type(result), result) 返回结果如下 <class 'urllib.parse.ParseResult'> ParseResult(scheme='http', netloc='www.baidu.com', path='/index.html', params='user', query='id=5', fragment='comment')
2. 1 URL中不写协议时,scheme参数指定协议类型
from urllib.parse import urlparse result = urlparse('www.baidu.com/index.html;user?id=5#comment', scheme='https') print(result) 返回结果如下 ParseResult(scheme='https', netloc='', path='www.baidu.com/index.html', params='user', query='id=5', fragment='comment')
2. 2 URL中有协议时,scheme参数指定协议类型无效
from urllib.parse import urlparse result = urlparse('http://www.baidu.com/index.html;user?id=5#comment', scheme='https') print(result) 返回结果 ParseResult(scheme='http', netloc='www.baidu.com', path='/index.html', params='user', query='id=5', fragment='comment')
3.1 allow_fragments:锚点链接
from urllib.parse import urlparse result = urlparse('http://www.baidu.com/index.html;user?id=5#comment', allow_fragments=False) print(result) 返回结果, 值为False时,锚点值拼接到query中 ParseResult(scheme='http', netloc='www.baidu.com', path='/index.html', params='user', query='id=5#comment', fragment='')
3.2 当query和params为空时,拼接到前面
from urllib.parse import urlparse result = urlparse('http://www.baidu.com/index.html#comment', allow_fragments=False) print(result) 返回结果 ParseResult(scheme='http', netloc='www.baidu.com', path='/index.html#comment', params='', query='', fragment='')
4. urlunparse模块,拼接url
from urllib.parse import urlunparse data = ['http', 'www.baidu.com', 'index.html', 'user', 'a=6', 'comment'] print(urlunparse(data))
返回结果:
http://www.baidu.com/index.html;user?a=6#comment
5. urljoin模块
有相同字段的URL,后面的覆盖前面的
from urllib.parse import urljoin print(urljoin('http://www.baidu.com', 'FAQ.html')) print(urljoin('http://www.baidu.com', 'https://cuiqingcai.com/FAQ.html')) print(urljoin('http://www.baidu.com/about.html', 'https://cuiqingcai.com/FAQ.html')) print(urljoin('http://www.baidu.com/about.html', 'https://cuiqingcai.com/FAQ.html?question=2')) print(urljoin('http://www.baidu.com?wd=abc', 'https://cuiqingcai.com/index.php')) print(urljoin('http://www.baidu.com', '?category=2#comment')) print(urljoin('www.baidu.com', '?category=2#comment')) print(urljoin('www.baidu.com#comment', '?category=2'))
返回结果为
6. urlencode模块:把字典对象转换为get请求参数
from urllib.parse import urlencode params = { 'name': 'germey', 'age': 22 } base_url = 'http://www.baidu.com?' url = base_url + urlencode(params) print(url)
返回