urllib.urlopen(url[,data[,proxies]])
打開一個url的方法，返回一個文件對象，然后可以進(jìn)行類似文件對象的操作
import urllib
f = urllib.urlopen('http://www.baudu.com/')
Get
如果我們要想模擬瀏覽器發(fā)送GET請求，就需要使用Request對象蚓挤，通過往Request對象添加HTTP頭蟹但，我們就可以把請求偽裝成瀏覽器逊笆。例如癣缅，模擬iPhone 6去請求豆瓣首頁
from urllib import request
req = request.Request('http://www.douban.com/')
req.add_header('User-Agent', 'Mozilla/6.0 (iPhone; CPU iPhone OS 8_0 like Mac OS X) AppleWebKit/536.26 (KHTML, like Gecko) Version/8.0 Mobile/10A5376e Safari/8536.25')
with request.urlopen(req) as f:
print('Status:', f.status, f.reason)
for k, v in f.getheaders():
print('%s: %s' % (k, v))
print('Data:', f.read().decode('utf-8'))
post
如果要以POST發(fā)送一個請求厨剪，只需要把參數(shù)data以bytes形式傳入勘畔。
我們模擬一個微博登錄，先讀取登錄的郵箱和口令丽惶，然后按照weibo.cn的登錄頁的格式以username=xxx&password=xxx的編碼傳入
from urllib import request, parse
print('Login to weibo.cn...')
email = input('Email: ')
passwd = input('Password: ')
login_data = parse.urlencode([
('username', email),
('password', passwd),
('entry', 'mweibo'),
('client_id', ''),
('savestate', '1'),
('ec', ''),
('pagerefer', 'https://passport.weibo.cn/signin/welcome?entry=mweibo&r=http%3A%2F%2Fm.weibo.cn%2F')
])
req = request.Request('https://passport.weibo.cn/sso/login')
req.add_header('Origin', 'https://passport.weibo.cn')
req.add_header('User-Agent', 'Mozilla/6.0 (iPhone; CPU iPhone OS 8_0 like Mac OS X) AppleWebKit/536.26 (KHTML, like Gecko) Version/8.0 Mobile/10A5376e Safari/8536.25')
req.add_header('Referer', 'https://passport.weibo.cn/signin/login?entry=mweibo&res=wel&wm=3349&r=http%3A%2F%2Fm.weibo.cn%2F')
with request.urlopen(req, data=login_data.encode('utf-8')) as f:
print('Status:', f.status, f.reason)
for k, v in f.getheaders():
print('%s: %s' % (k, v))
print('Data:', f.read().decode('utf-8'))
Handler
如果還需要更復(fù)雜的控制，比如通過一個Proxy去訪問網(wǎng)站爬立，我們需要利用ProxyHandler來處理
proxy_handler = urllib.request.ProxyHandler({'http': 'http://www.example.com:3128/'})
proxy_auth_handler = urllib.request.ProxyBasicAuthHandler()
proxy_auth_handler.add_password('realm', 'host', 'username', 'password')
opener = urllib.request.build_opener(proxy_handler, proxy_auth_handler)
with opener.open('http://www.example.com/login.html') as f:
pass
urllib提供的功能就是利用程序去執(zhí)行各種HTTP請求钾唬。如果要模擬瀏覽器完成特定功能，需要把請求偽裝成瀏覽器侠驯。偽裝的方法是先監(jiān)控瀏覽器發(fā)出的請求抡秆，再根據(jù)瀏覽器的請求頭來偽裝，User-Agent頭就是用來標(biāo)識瀏覽器的
