这两天学习了python3实现抓取网页资源的方法，发现了很多种方法，所以，今天添加一点小笔记。

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

import urllib.requestreq = urllib.request.Request('http://python.org/')
response = urllib.request.urlopen(req)
the_page = response.read()
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3、发送数据

#! /usr/bin/env python3import urllib.parse
import urllib.requesturl = 'http://localhost/login.php'
user_agent = 'Mozilla/4.0 (compatible; MSIE 5.5; Windows NT)'
values = {'act' : 'login','login[email]' : 'yzhang@i9i8.com','login[password]' : '123456'}data = urllib.parse.urlencode(values)
req = urllib.request.Request(url, data)
req.add_header('Referer', 'http://www.python.org/')
response = urllib.request.urlopen(req)
the_page = response.read()print(the_page.decode("utf8"))
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4、发送数据和header

#! /usr/bin/env python3import urllib.parse
import urllib.requesturl = 'http://localhost/login.php'
user_agent = 'Mozilla/4.0 (compatible; MSIE 5.5; Windows NT)'
values = {'act' : 'login','login[email]' : 'yzhang@i9i8.com','login[password]' : '123456'}
headers = { 'User-Agent' : user_agent }data = urllib.parse.urlencode(values)
req = urllib.request.Request(url, data, headers)
response = urllib.request.urlopen(req)
the_page = response.read()print(the_page.decode("utf8"))
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5、http 错误

#! /usr/bin/env python3import urllib.requestreq = urllib.request.Request('http://www.python.org/fish.html')
try:urllib.request.urlopen(req)
except urllib.error.HTTPError as e:print(e.code)print(e.read().decode("utf8"))
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6、异常处理1

#! /usr/bin/env python3from urllib.request import Request, urlopen
from urllib.error import URLError, HTTPError
req = Request("http://twitter.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"))
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7、异常处理2

#! /usr/bin/env python3from urllib.request import Request, urlopen
from urllib.error import URLError
req = Request("http://twitter.com/")
try:response = urlopen(req)
except URLError as e:if hasattr(e, 'reason'):print('We failed to reach a server.')print('Reason: ', e.reason)elif hasattr(e, 'code'):print('The server couldn\'t fulfill the request.')print('Error code: ', e.code)
else:print("good!")print(response.read().decode("utf8"))
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8、HTTP 认证

#! /usr/bin/env python3import 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://cms.tetx.com/"
password_mgr.add_password(None, top_level_url, 'yzhang', 'cccddd')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://cms.tetx.com/"
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)
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9、使用代理

#! /usr/bin/env python3import urllib.requestproxy_support = urllib.request.ProxyHandler({'sock5': 'localhost:1080'})
opener = urllib.request.build_opener(proxy_support)
urllib.request.install_opener(opener)a = urllib.request.urlopen("http://g.cn").read().decode("utf8")
print(a)
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10、超时

#! /usr/bin/env python3import 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://twitter.com/')
a = urllib.request.urlopen(req).read()
print(a)
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