收藏好文，看的懂文档，但效率太慢
cookie 清空
import urllib2
import cookielib
from time import sleep cookie=cookielib.CookieJar()
opener = urllib2.build_opener(urllib2.HTTPCookieProcessor(cookie))
for n in range(6):
response = opener.open('http://www.docin.com/p-976549025.html?utm_source=keda&utm_medium=20150406&utm_campaign=a20401')
sleep(6)
cookie.clear()
Proxy 的设置
urllib2 默认会使用环境变量 http_proxy 来设置 HTTP Proxy。如果想在程序中明确控制 Proxy 而不受环境变量的影响，可以使用下面的方式
import urllib2
enable_proxy = True
proxy_handler = urllib2.ProxyHandler({"http" : 'http://some-proxy.com:8080'})
null_proxy_handler = urllib2.ProxyHandler({})
if enable_proxy:
opener = urllib2.build_opener(proxy_handler)
else:
opener = urllib2.build_opener(null_proxy_handler)
urllib2.install_opener(opener)
这里要注意的一个细节，使用 urllib2.install_opener() 会设置 urllib2 的全局 opener 。这样后面的使用会很方便，但不能做更细粒度的控制，比如想在程序中使用两个不同的 Proxy 设置等。比较好的做法是不使用 install_opener 去更改全局的设置，而只是直接调用 opener 的 open方法代替全局的 urlopen 方法。
Timeout 设置
在老版 Python 中，urllib2 的 API 并没有暴露 Timeout 的设置，要设置 Timeout 值，只能更改 Socket 的全局 Timeout 值。
import urllib2
import socket
socket.setdefaulttimeout(10) # 10 秒钟后超时
urllib2.socket.setdefaulttimeout(10) # 另一种方式
在 Python 2.6 以后，超时可以通过 urllib2.urlopen() 的 timeout 参数直接设置。
import urllib2
response = urllib2.urlopen('http://www.google.com', timeout=10)
在 HTTP Request 中加入特定的 Header
要加入 header，需要使用 Request 对象：
import urllib2
request = urllib2.Request(uri)
request.add_header('User-Agent', 'fake-client')
response = urllib2.urlopen(request)
对有些 header 要特别留意，服务器会针对这些 header 做检查
User-Agent : 有些服务器或 Proxy 会通过该值来判断是否是浏览器发出的请求
Content-Type : 在使用 REST 接口时，服务器会检查该值，用来确定 HTTP Body 中的内容该怎样解析。常见的取值有：
application/xml ： 在 XML RPC，如 RESTful/SOAP 调用时使用
application/json ： 在 JSON RPC 调用时使用
application/x-www-form-urlencoded ： 浏览器提交 Web 表单时使用
在使用服务器提供的 RESTful 或 SOAP 服务时， Content-Type 设置错误会导致服务器拒绝服务
Redirect
urllib2 默认情况下会针对 HTTP 3XX 返回码自动进行 redirect 动作，无需人工配置。要检测是否发生了 redirect 动作，只要检查一下 Response 的 URL 和 Request 的 URL 是否一致就可以了。
import urllib2
response = urllib2.urlopen('http://www.google.cn')
redirected = response.geturl() == 'http://www.google.cn'
如果不想自动 redirect，除了使用更低层次的 httplib 库之外，还可以自定义HTTPRedirectHandler 类。
import urllib2
class RedirectHandler(urllib2.HTTPRedirectHandler):
def http_error_301(self, req, fp, code, msg, headers):
pass
def http_error_302(self, req, fp, code, msg, headers):
pass
opener = urllib2.build_opener(RedirectHandler)
opener.open('http://www.google.cn')
Cookie
urllib2 对 Cookie 的处理也是自动的。如果需要得到某个 Cookie 项的值，可以这么做：
import urllib2
import cookielib
cookie = cookielib.CookieJar()
opener = urllib2.build_opener(urllib2.HTTPCookieProcessor(cookie))
response = opener.open('http://www.google.com')
for item in cookie:
if item.name == 'some_cookie_item_name':
print item.value
使用 HTTP 的 PUT 和 DELETE 方法
urllib2 只支持 HTTP 的 GET 和 POST 方法，如果要使用 HTTP PUT 和 DELETE ，只能使用比较低层的 httplib 库。虽然如此，我们还是能通过下面的方式，使 urllib2 能够发出 PUT 或 DELETE 的请求：
import urllib2
request = urllib2.Request(uri, data=data)
request.get_method = lambda: 'PUT' # or 'DELETE'
response = urllib2.urlopen(request)
这种做法虽然属于 Hack 的方式，但实际使用起来也没什么问题。
得到 HTTP 的返回码
对于 200 OK 来说，只要使用 urlopen 返回的 response 对象的 getcode() 方法就可以得到 HTTP 的返回码。但对其它返回码来说，urlopen 会抛出异常。这时候，就要检查异常对象的 code 属性了：
import urllib2
try:
response = urllib2.urlopen('http://restrict.web.com')
except urllib2.HTTPError, e:
print e.code
Debug Log
使用 urllib2 时，可以通过下面的方法把 debug Log 打开，这样收发包的内容就会在屏幕上打印出来，方便调试，有时可以省去抓包的工作
import urllib2
httpHandler = urllib2.HTTPHandler(debuglevel=1)
httpsHandler = urllib2.HTTPSHandler(debuglevel=1)
opener = urllib2.build_opener(httpHandler, httpsHandler)
urllib2.install_opener(opener)
response = urllib2.urlopen('http://www.google.com')
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fetch urls
response=urlopen->http:// or ftp://
response is a file-like object response.read()
import urllib.request
response = urllib.request.urlopen('http://python.org/')
html = response.read()
OR
req = urllib.request.Request('http://www.voidspace.org.uk')
response = urllib.request.urlopen(req)
the_page = response.read()
POST (sent data to) | GET
1 import urllib.parse //post
2 import urllib.request
3
4 url = 'http://www.someserver.com/cgi-bin/register.cgi'
5 values = {'name' : 'Michael Foord',
6 'location' : 'Northampton',
7 'language' : 'Python' }
8
9 data = urllib.parse.urlencode(values) //convert to HTML form
10 req = urllib.request.Request(url, data)
11 response = urllib.request.urlopen(req)
12 the_page = response.read()
GET
url = 'http://www.example.com/example.cgi'
full_url = url + '?' + url_values
data = urllib.request.open(full_url)
add headers
values = {'name' : 'Michael Foord',
'location' : 'Northampton',
'language' : 'Python' }
headers = { 'User-Agent' : user_agent }
data = urllib.parse.urlencode(values)
req = urllib.request.Request(url, data, headers)
response = urllib.request.urlopen(req)
catch url error
try:
urllib.request.urlopen(req)
excep urllib.error.URLError as e:
print(e.reaseon)
cat HTTPError
req=urllib.request.Request('www...')
try:
urllib.request.urlopen(req)
except urllib.error.HTTPError as e:
print(e.code) //404 or e.g.
print(e.read()) // <!D...html>
Warpping up
1 from urllib.request import Request, urlopen
2 from urllib.error import URLError
3 req = Request(someurl)
4 try:
5 response = urlopen(req)
6 except URLError as e:
7 if hasattr(e, 'reason'):
8 print('We failed to reach a server.')
9 print('Reason: ', e.reason)
10 elif hasattr(e, 'code'):
11 print('The server couldn\'t fulfill the request.')
12 print('Error code: ', e.code)
13 else:
14 # everything is fine
info and geturl
The response returned by urlopen (or the HTTPError instance) has two useful methods info() and geturl()
geturl - this returns the real URL of the page fetched(not by redirected)//may in script,it's better to use geturl() instead of read()
Typical headers include 'Content-length', 'Content-type', and so on.
info - this returns a dictionary-like object that describes the page fetched, particularly the headers sent by the server. It is currently an http.client.HTTPMessage instance.
URL authentic needed
# 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.//域
top_level_url = "http://example.com/foo/" //e.g. 82.0.0.35:9090(H3C bims)
password_mgr.add_password(None, top_level_url, username, password)
handler = urllib.request.HTTPBasicAuthHandler(password_mgr)
# create "opener" (OpenerDirector instance)
opener = urllib.request.build_opener(handler)
# use the opener to fetch a URL
opener.open(a_url)
# Install the opener.
# Now all calls to urllib.request.urlopen use our opener.
urllib.request.install_opener(opener)
Proxy
setting up a Basic Authentication handler
proxy_support = urllib.request.ProxyHandler({})
opener = urllib.request.build_opener(proxy_support)
urllib.request.install_opener(opener)
Set timeout
1 import socket
2 import urllib.request
3
4 # timeout in seconds
5 timeout = 10
6 socket.setdefaulttimeout(timeout)
7
8 # this call to urllib.request.urlopen now uses the default timeout
9 # we have set in the socket module
10 req = urllib.request.Request('http://www.voidspace.org.uk')
11 response = urllib.request.urlopen(req)
to read
Quick Reference to HTTP Headers
HTTP Error code:
# Table mapping response codes to messages; entries have the
# form {code: (shortmessage, longmessage)}.
responses = {
100: ('Continue', 'Request received, please continue'),
101: ('Switching Protocols',
'Switching to new protocol; obey Upgrade header'),
200: ('OK', 'Request fulfilled, document follows'),
201: ('Created', 'Document created, URL follows'),
202: ('Accepted',
'Request accepted, processing continues off-line'),
203: ('Non-Authoritative Information', 'Request fulfilled from cache'),
204: ('No Content', 'Request fulfilled, nothing follows'),
205: ('Reset Content', 'Clear input form for further input.'),
206: ('Partial Content', 'Partial content follows.'),
300: ('Multiple Choices',
'Object has several resources -- see URI list'),
301: ('Moved Permanently', 'Object moved permanently -- see URI list'),
302: ('Found', 'Object moved temporarily -- see URI list'),
303: ('See Other', 'Object moved -- see Method and URL list'),
304: ('Not Modified',
'Document has not changed since given time'),
305: ('Use Proxy',
'You must use proxy specified in Location to access this '
'resource.'),
307: ('Temporary Redirect',
'Object moved temporarily -- see URI list'),
400: ('Bad Request',
'Bad request syntax or unsupported method'),
401: ('Unauthorized',
'No permission -- see authorization schemes'),
402: ('Payment Required',
'No payment -- see charging schemes'),
403: ('Forbidden',
'Request forbidden -- authorization will not help'),
404: ('Not Found', 'Nothing matches the given URI'),
405: ('Method Not Allowed',
'Specified method is invalid for this server.'),
406: ('Not Acceptable', 'URI not available in preferred format.'),
407: ('Proxy Authentication Required', 'You must authenticate with '
'this proxy before proceeding.'),
408: ('Request Timeout', 'Request timed out; try again later.'),
409: ('Conflict', 'Request conflict.'),
410: ('Gone',
'URI no longer exists and has been permanently removed.'),
411: ('Length Required', 'Client must specify Content-Length.'),
412: ('Precondition Failed', 'Precondition in headers is false.'),
413: ('Request Entity Too Large', 'Entity is too large.'),
414: ('Request-URI Too Long', 'URI is too long.'),
415: ('Unsupported Media Type', 'Entity body in unsupported format.'),
416: ('Requested Range Not Satisfiable',
'Cannot satisfy request range.'),
417: ('Expectation Failed',
'Expect condition could not be satisfied.'),
500: ('Internal Server Error', 'Server got itself in trouble'),
501: ('Not Implemented',
'Server does not support this operation'),
502: ('Bad Gateway', 'Invalid responses from another server/proxy.'),
503: ('Service Unavailable',
'The server cannot process the request due to a high load'),
504: ('Gateway Timeout',
'The gateway server did not receive a timely response'),
505: ('HTTP Version Not Supported', 'Cannot fulfill request.'),
}
example @ cyou