urllib2：如何安裝代理和http基本身份驗證處理程序作爲openers？

Question

背景：由於環境的限制，我堅持使用python 2.4。所以requests是不可能的。

我希望能夠同時使用urllib2.HTTPBasicAuthHandler和ProxyHandler打開一個url。

如果我做這樣的事情：

proxy = urllib2.ProxyHandler({'http': 'http://myproxy.local'}) 
proxy_opener = urllib2.build_opener(proxy) 

... 
passman = urllib2.HTTPPasswordMgrWithDefaultRealm() 
pass_handler = urllib2.HTTPBasicAuthHandler(passman) 
... 
urllib2.install_opener(urllib2.build_opener([proxy_opener, pass_handler])) 

的代碼將停留在這一行：

urllib2.urlopen(target_url) 

那麼，什麼是安裝兩個處理器的正確方法？

編輯：

我原來的版本有語法錯誤。該生產線

urllib2.install_opener(urllib2.build_opener(pass_handler), proxy_opener) 

應該

urllib2.install_opener(urllib2.build_opener(pass_handler, proxy_opener)) # note the parenthesis 

但作爲atupal表明，它應該是

urllib2.install_opener(urllib2.build_opener([proxy_opener, pass_handler])) 

Answer 1

閱讀docs-install_opener和docs-build_opener

urllib2.install_opener(opener)

Install an OpenerDirector instance as the default global opener.

和urllib2.build_opener([handler, ...])

Return an OpenerDirector instance, which chains the handlers in the order given. handlers can be either instances of BaseHandler, or subclasses of BaseHandler (in which case it must be possible to call the constructor without any parameters). Instances of the following classes will be in front of the handlers, unless the handlers contain them, instances of them or subclasses of them: ProxyHandler (if proxy settings are detected), UnknownHandler, HTTPHandler, HTTPDefaultErrorHandler, HTTPRedirectHandler, FTPHandler, FileHandler, HTTPErrorProcessor.

所以，你應該先建立一個開門紅使用代理處理程序，並權威性的處理程序。並安裝它globaly如果你想：

proxy_handler = urllib2.ProxyHandler({'http': 'http://myproxy.local'}) 

... 
passman = urllib2.HTTPPasswordMgrWithDefaultRealm() 
pass_handler = urllib2.HTTPBasicAuthHandler(passman) 
... 
urllib2.install_opener(urllib2.build_opener(proxy_handler, pass_handler)) 

更新： 我測試下面的代碼片段，它可以作爲預期。不要忘記用自己更換代理，URL，用戶名和密碼：

import urllib2 

proxyhandler = urllib2.ProxyHandler({'http': 'http://219.93.183.106:8080'}) 

url = "http://atupal.org:9001" 
passman = urllib2.HTTPPasswordMgrWithDefaultRealm() 
passman.add_password(None, url, "myusername", "mypassword") 
pass_handler = urllib2.HTTPBasicAuthHandler(passman) 

opener = urllib2.build_opener(
    proxyhandler, 
    pass_handler, 
    ) 
urllib2.install_opener(opener) 

print urllib2.urlopen(url).read()