20.6. urllib2 — 用于打开 URL 的可扩展库 ¶

注意

The urllib2 module has been split across several modules in Python 3 named urllib.request and urllib.error 。 2to3 tool will automatically adapt imports when converting your sources to Python 3.

The urllib2 模块定义有助于在复杂环境打开 URL (主要是 HTTP) 的函数和类 — 基本和摘要身份验证、重定向、Cookie 等。

另请参阅

The Requests 包 推荐为更高级别的 HTTP 客户端接口。

The urllib2 模块定义了下列函数：

urllib2. urlopen ( url[, data[, timeout[, cafile[, capath[, cadefault[, context]]]]] ) ¶

打开 URL url ，其可以是字符串或 Request 对象。

data may be a string specifying additional data to send to the server, or None 若不需要这样的数据。目前，仅 HTTP 请求使用 data ; the HTTP request will be a POST instead of a GET when the data parameter is provided. data 应该是缓冲，采用标准 application/x-www-form-urlencoded 格式。 urllib.urlencode() function takes a mapping or sequence of 2-tuples and returns a string in this format. urllib2 module sends HTTP/1.1 requests with Connection:close header included.

可选 timeout 参数指定超时 (以秒为单位) 为阻塞像连接尝试操作 (若未指定，将使用全局默认超时设置)。这实际仅工作于 HTTP HTTPS 及 FTP 连接。

若 context 被指定，它必须是 ssl.SSLContext 实例 (描述各种 SSL 选项)。见 HTTPSConnection 了解更多细节。

可选 cafile and capath 参数为 HTTPS 请求指定一组受信任的 CA 证书。 cafile 应该指向包含一捆 CA 证书的单个文件，而 capath 应该指向哈希证书文件目录。可以找到更多信息在 ssl.SSLContext.load_verify_locations() .

The cadefault 参数被忽略。

This function returns a file-like object with three additional methods:

• geturl() — return the URL of the resource retrieved, commonly used to determine if a redirect was followed

• info() — return the meta-information of the page, such as headers, in the form of an mimetools.Message 实例 (见 快速参考 HTTP 头 )

• getcode() — return the HTTP status code of the response.

引发 URLError on errors.

注意， None 可能被返回，若没有处理程序处理请求 (虽然默认安装了全局 OpenerDirector 使用 UnknownHandler 以确保这从不发生)。

此外，若检测到代理设置 (例如，当 *_proxy 环境变量像 http_proxy 有设置)， ProxyHandler ProxyHandler 是默认安装的，并确保透过代理处理请求。

2.6 版改变： timeout 被添加。

Changed in version 2.7.9: cafile , capath , cadefault ，和 context 被添加。

urllib2. install_opener ( opener ) ¶

安装 OpenerDirector instance as the default global opener. Installing an opener is only necessary if you want urlopen to use that opener; otherwise, simply call OpenerDirector.open() 而不是 urlopen() . The code does not check for a real OpenerDirector , and any class with the appropriate interface will work.

urllib2. build_opener ( [ handler , ... ] ) ¶

返回 OpenerDirector instance, which chains the handlers in the order given. handler s 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 handler s, unless the handler s contain them, instances of them or subclasses of them: ProxyHandler (if proxy settings are detected), UnknownHandler , HTTPHandler , HTTPDefaultErrorHandler , HTTPRedirectHandler , FTPHandler , FileHandler , HTTPErrorProcessor .

若 Python 安装有 SSL 支持 (即：若 ssl 模块可以被导入)， HTTPSHandler will also be added.

Beginning in Python 2.3, a BaseHandler 子类还可以改变其 handler_order attribute to modify its position in the handlers list.

The following exceptions are raised as appropriate:

exception urllib2. URLError ¶

The handlers raise this exception (or derived exceptions) when they run into a problem. It is a subclass of IOError .

reason ¶

The reason for this error. It can be a message string or another exception instance ( socket.error for remote URLs, OSError for local URLs).

exception urllib2. HTTPError ¶

Though being an exception (a subclass of URLError ), an HTTPError can also function as a non-exceptional file-like return value (the same thing that urlopen() returns). This is useful when handling exotic HTTP errors, such as requests for authentication.

code ¶

An HTTP status code as defined in RFC 2616 . This numeric value corresponds to a value found in the dictionary of codes as found in BaseHTTPServer.BaseHTTPRequestHandler.responses .

reason ¶

The reason for this error. It can be a message string or another exception instance.

提供了下列类：

class urllib2. Request ( url[, data][, headers][, origin_req_host][, unverifiable] ) ¶

此类是 URL 请求的抽象。

url 应是包含有效 URL 的字符串。

data may be a string specifying additional data to send to the server, or None 若不需要这样的数据。目前，仅 HTTP 请求使用 data ; the HTTP request will be a POST instead of a GET when the data parameter is provided. data 应该是缓冲，采用标准 application/x-www-form-urlencoded 格式。 urllib.urlencode() function takes a mapping or sequence of 2-tuples and returns a string in this format.

headers should be a dictionary, and will be treated as if add_header() was called with each key and value as arguments. This is often used to “spoof” the User-Agent header value, which is used by a browser to identify itself – some HTTP servers only allow requests coming from common browsers as opposed to scripts. For example, Mozilla Firefox may identify itself as "Mozilla/5.0 (X11; U; Linux i686) Gecko/20071127 Firefox/2.0.0.11" ，而 urllib2 的默认用户代理字符串是 "Python-urllib/2.6" (在 Python 2.6)。

最后 2 自变量仅对正确处理第 3 方 HTTP Cookie 感兴趣：

origin_req_host 应该是原始事务请求主机，作为定义通过 RFC 2965 。默认为 cookielib.request_host(self) . This is the host name or IP address of the original request that was initiated by the user. For example, if the request is for an image in an HTML document, this should be the request-host of the request for the page containing the image.

unverifiable should indicate whether the request is unverifiable, as defined by RFC 2965. It defaults to False . An unverifiable request is one whose URL the user did not have the option to approve. For example, if the request is for an image in an HTML document, and the user had no option to approve the automatic fetching of the image, this should be true.

class urllib2. OpenerDirector ¶

The OpenerDirector 类打开 URL 凭借 BaseHandler s chained together. It manages the chaining of handlers, and recovery from errors.

class urllib2. BaseHandler ¶

This is the base class for all registered handlers — and handles only the simple mechanics of registration.

class urllib2. HTTPDefaultErrorHandler ¶

A class which defines a default handler for HTTP error responses; all responses are turned into HTTPError 异常。

class urllib2. HTTPRedirectHandler ¶

处理重定向的类。

class urllib2. HTTPCookieProcessor ( [ cookiejar ] ) ¶

处理 HTTP Cookie 的类。

class urllib2. ProxyHandler ( [ proxies ] ) ¶

促使请求透过代理进行。若 proxies is given, it must be a dictionary mapping protocol names to URLs of proxies. The default is to read the list of proxies from the environment variables <protocol>_proxy . If no proxy environment variables are set, then in a Windows environment proxy settings are obtained from the registry’s Internet Settings section, and in a Mac OS X environment proxy information is retrieved from the OS X System Configuration Framework.

要禁用自动检测代理，传递空字典。

注意

HTTP_PROXY 会被忽略若变量 REQUEST_METHOD 被设置；见文档编制 getproxies() .

class urllib2. HTTPPasswordMgr ¶

保持数据库的 (realm, uri) -> (user, password) 映射。

class urllib2. HTTPPasswordMgrWithDefaultRealm ¶

保持数据库的 (realm, uri) -> (user, password) mappings. A realm of None is considered a catch-all realm, which is searched if no other realm fits.

class urllib2. AbstractBasicAuthHandler ( [ password_mgr ] ) ¶

This is a mixin class that helps with HTTP authentication, both to the remote host and to a proxy. password_mgr , if given, should be something that is compatible with HTTPPasswordMgr ; refer to section HTTPPasswordMgr 对象 for information on the interface that must be supported.

class urllib2. HTTPBasicAuthHandler ( [ password_mgr ] ) ¶

Handle authentication with the remote host. password_mgr , if given, should be something that is compatible with HTTPPasswordMgr ; refer to section HTTPPasswordMgr 对象 for information on the interface that must be supported.

class urllib2. ProxyBasicAuthHandler ( [ password_mgr ] ) ¶

Handle authentication with the proxy. password_mgr , if given, should be something that is compatible with HTTPPasswordMgr ; refer to section HTTPPasswordMgr 对象 for information on the interface that must be supported.

class urllib2. AbstractDigestAuthHandler ( [ password_mgr ] ) ¶

This is a mixin class that helps with HTTP authentication, both to the remote host and to a proxy. password_mgr , if given, should be something that is compatible with HTTPPasswordMgr ; refer to section HTTPPasswordMgr 对象 for information on the interface that must be supported.

class urllib2. HTTPDigestAuthHandler ( [ password_mgr ] ) ¶

Handle authentication with the remote host. password_mgr , if given, should be something that is compatible with HTTPPasswordMgr ; refer to section HTTPPasswordMgr 对象 for information on the interface that must be supported.

class urllib2. ProxyDigestAuthHandler ( [ password_mgr ] ) ¶

Handle authentication with the proxy. password_mgr , if given, should be something that is compatible with HTTPPasswordMgr ; refer to section HTTPPasswordMgr 对象 for information on the interface that must be supported.

class urllib2. HTTPHandler ¶

处理打开 HTTP URL 的类。

class urllib2. HTTPSHandler ( [ debuglevel [ , context ] ] ) ¶

A class to handle opening of HTTPS URLs. context has the same meaning as for httplib.HTTPSConnection .

Changed in version 2.7.9: context added.

class urllib2. FileHandler ¶

打开本地文件。

class urllib2. FTPHandler ¶

打开 FTP URL。

class urllib2. CacheFTPHandler ¶

打开 FTP URL，保持打开 FTP 连接的缓存以最小化延迟。

class urllib2. UnknownHandler ¶

A catch-all class to handle unknown URLs.

class urllib2. HTTPErrorProcessor ¶

处理 HTTP 错误响应。

20.6.1. Request 对象 ¶

The following methods describe all of Request ’s public interface, and so all must be overridden in subclasses.

Request. add_data ( data ) ¶

设置 Request data to data . This is ignored by all handlers except HTTP handlers — and there it should be a byte string, and will change the request to be POST 而不是 GET .

Request. get_method ( ) ¶

Return a string indicating the HTTP request method. This is only meaningful for HTTP requests, and currently always returns 'GET' or 'POST' .

Request. has_data ( ) ¶

Return whether the instance has a non- None 数据。

Request. get_data ( ) ¶

Return the instance’s data.

Request. add_header ( key , val ) ¶

Add another header to the request. Headers are currently ignored by all handlers except HTTP handlers, where they are added to the list of headers sent to the server. Note that there cannot be more than one header with the same name, and later calls will overwrite previous calls in case the key collides. Currently, this is no loss of HTTP functionality, since all headers which have meaning when used more than once have a (header-specific) way of gaining the same functionality using only one header.

Request. add_unredirected_header ( key , header ) ¶

添加不会被添加到重定向请求的 Header 头。

2.4 版新增。

Request. has_header ( header ) ¶

Return whether the instance has the named header (checks both regular and unredirected).

2.4 版新增。

Request. get_full_url ( ) ¶

返回在构造函数中给定的 URL。

Request. get_type ( ) ¶

Return the type of the URL — also known as the scheme.

Request. get_host ( ) ¶

Return the host to which a connection will be made.

Request. get_selector ( ) ¶

Return the selector — the part of the URL that is sent to the server.

Request. get_header ( header_name , default=None ) ¶

Return the value of the given header. If the header is not present, return the default value.

Request. header_items ( ) ¶

Return a list of tuples (header_name, header_value) of the Request headers.

Request. set_proxy ( host , type ) ¶

Prepare the request by connecting to a proxy server. The host and type will replace those of the instance, and the instance’s selector will be the original URL given in the constructor.

Request. get_origin_req_host ( ) ¶

Return the request-host of the origin transaction, as defined by RFC 2965 . See the documentation for the Request 构造函数。

Request. is_unverifiable ( ) ¶

Return whether the request is unverifiable, as defined by RFC 2965. See the documentation for the Request 构造函数。

20.6.2. OpenerDirector 对象 ¶

OpenerDirector 实例具有下列方法：

OpenerDirector. add_handler ( handler ) ¶

handler should be an instance of BaseHandler . The following methods are searched, and added to the possible chains (note that HTTP errors are a special case).

• protocol_open — signal that the handler knows how to open protocol URLs.

• http_error_type — signal that the handler knows how to handle HTTP errors with HTTP error code type .

• protocol_error — signal that the handler knows how to handle errors from (non- http ) protocol .

• protocol_request — signal that the handler knows how to pre-process protocol requests.

• protocol_response — signal that the handler knows how to post-process protocol responses.

OpenerDirector. open ( url[, data][, timeout] ) ¶

打开给定 url (which can be a request object or a string), optionally passing the given data . Arguments, return values and exceptions raised are the same as those of urlopen() (which simply calls the open() method on the currently installed global OpenerDirector ). The optional timeout parameter specifies a timeout in seconds for blocking operations like the connection attempt (if not specified, the global default timeout setting will be used). The timeout feature actually works only for HTTP, HTTPS and FTP connections).

2.6 版改变： timeout 被添加。

OpenerDirector. error ( proto [ , arg [ , ... ] ] ) ¶

Handle an error of the given protocol. This will call the registered error handlers for the given protocol with the given arguments (which are protocol specific). The HTTP protocol is a special case which uses the HTTP response code to determine the specific error handler; refer to the http_error_*() methods of the handler classes.

Return values and exceptions raised are the same as those of urlopen() .

OpenerDirector 对象按 3 阶段打开 URL：

The order in which these methods are called within each stage is determined by sorting the handler instances.

1. Every handler with a method named like protocol_request has that method called to pre-process the request.

2. Handlers with a method named like protocol_open are called to handle the request. This stage ends when a handler either returns a non- None value (ie. a response), or raises an exception (usually URLError ). Exceptions are allowed to propagate.

   In fact, the above algorithm is first tried for methods named default_open() . If all such methods return None , the algorithm is repeated for methods named like protocol_open . If all such methods return None , the algorithm is repeated for methods named unknown_open() .

   Note that the implementation of these methods may involve calls of the parent OpenerDirector instance’s open() and error() 方法。

3. Every handler with a method named like protocol_response has that method called to post-process the response.

20.6.3. BaseHandler 对象 ¶

BaseHandler objects provide a couple of methods that are directly useful, and others that are meant to be used by derived classes. These are intended for direct use:

BaseHandler. add_parent ( director ) ¶

Add a director as parent.

BaseHandler. close ( ) ¶

移除任何父级。

The following attributes and methods should only be used by classes derived from BaseHandler .

注意

The convention has been adopted that subclasses defining protocol_request() or protocol_response() methods are named *Processor ; all others are named *Handler .

BaseHandler. parent ¶

有效 OpenerDirector , which can be used to open using a different protocol, or handle errors.

BaseHandler. default_open ( req ) ¶

This method is not defined in BaseHandler , but subclasses should define it if they want to catch all URLs.

This method, if implemented, will be called by the parent OpenerDirector . It should return a file-like object as described in the return value of the open() of OpenerDirector ，或 None . It should raise URLError , unless a truly exceptional thing happens (for example, MemoryError should not be mapped to URLError ).

This method will be called before any protocol-specific open method.

BaseHandler. protocol_open ( req )

(“protocol” is to be replaced by the protocol name.)

This method is not defined in BaseHandler , but subclasses should define it if they want to handle URLs with the given protocol .

This method, if defined, will be called by the parent OpenerDirector . Return values should be the same as for default_open() .

BaseHandler. unknown_open ( req ) ¶

This method is not defined in BaseHandler , but subclasses should define it if they want to catch all URLs with no specific registered handler to open it.

This method, if implemented, will be called by the parent OpenerDirector . Return values should be the same as for default_open() .

BaseHandler. http_error_default ( req , fp , code , msg , hdrs ) ¶

This method is not defined in BaseHandler , but subclasses should override it if they intend to provide a catch-all for otherwise unhandled HTTP errors. It will be called automatically by the OpenerDirector getting the error, and should not normally be called in other circumstances.

req 将是 Request 对象， fp will be a file-like object with the HTTP error body, code will be the three-digit code of the error, msg will be the user-visible explanation of the code and hdrs will be a mapping object with the headers of the error.

Return values and exceptions raised should be the same as those of urlopen() .

BaseHandler. http_error_nnn ( req , fp , code , msg , hdrs ) ¶

nnn should be a three-digit HTTP error code. This method is also not defined in BaseHandler , but will be called, if it exists, on an instance of a subclass, when an HTTP error with code nnn 出现。

Subclasses should override this method to handle specific HTTP errors.

Arguments, return values and exceptions raised should be the same as for http_error_default() .

BaseHandler. protocol_request ( req )

(“protocol” is to be replaced by the protocol name.)

This method is not defined in BaseHandler , but subclasses should define it if they want to pre-process requests of the given protocol .

This method, if defined, will be called by the parent OpenerDirector . req 将是 Request object. The return value should be a Request 对象。

BaseHandler. protocol_response ( req , response )

(“protocol” is to be replaced by the protocol name.)

This method is not defined in BaseHandler , but subclasses should define it if they want to post-process responses of the given protocol .

This method, if defined, will be called by the parent OpenerDirector . req 将是 Request 对象。 response will be an object implementing the same interface as the return value of urlopen() . The return value should implement the same interface as the return value of urlopen() .

20.6.4. HTTPRedirectHandler 对象 ¶

注意

Some HTTP redirections require action from this module’s client code. If this is the case, HTTPError 被引发。见 RFC 2616 for details of the precise meanings of the various redirection codes.

HTTPRedirectHandler. redirect_request ( req , fp , code , msg , hdrs , newurl ) ¶

返回 Request or None in response to a redirect. This is called by the default implementations of the http_error_30*() methods when a redirection is received from the server. If a redirection should take place, return a new Request to allow http_error_30*() to perform the redirect to newurl . Otherwise, raise HTTPError if no other handler should try to handle this URL, or return None if you can’t but another handler might.

注意

The default implementation of this method does not strictly follow RFC 2616 , which says that 301 and 302 responses to POST requests must not be automatically redirected without confirmation by the user. In reality, browsers do allow automatic redirection of these responses, changing the POST to a GET , and the default implementation reproduces this behavior.

HTTPRedirectHandler. http_error_301 ( req , fp , code , msg , hdrs ) ¶

重定向到 Location: or URI: URL. This method is called by the parent OpenerDirector when getting an HTTP ‘moved permanently’ response.

HTTPRedirectHandler. http_error_302 ( req , fp , code , msg , hdrs ) ¶

如同 http_error_301() , but called for the ‘found’ response.

HTTPRedirectHandler. http_error_303 ( req , fp , code , msg , hdrs ) ¶

如同 http_error_301() , but called for the ‘see other’ response.

HTTPRedirectHandler. http_error_307 ( req , fp , code , msg , hdrs ) ¶

如同 http_error_301() , but called for the ‘temporary redirect’ response.

20.6.5. HTTPCookieProcessor 对象 ¶

2.4 版新增。

HTTPCookieProcessor 实例有一属性：

HTTPCookieProcessor. cookiejar ¶

The cookielib.CookieJar 在其中存储 Cookie。

20.6.6. ProxyHandler 对象 ¶

ProxyHandler. protocol_open ( request )

(“protocol” is to be replaced by the protocol name.)

The ProxyHandler will have a method protocol_open for every protocol which has a proxy in the proxies dictionary given in the constructor. The method will modify requests to go through the proxy, by calling request.set_proxy() , and call the next handler in the chain to actually execute the protocol.

20.6.7. HTTPPasswordMgr 对象 ¶

这些方法可用于 HTTPPasswordMgr and HTTPPasswordMgrWithDefaultRealm 对象。

HTTPPasswordMgr. add_password ( realm , uri , user , passwd ) ¶

uri can be either a single URI, or a sequence of URIs. realm , user and passwd must be strings. This causes (user, passwd) to be used as authentication tokens when authentication for realm and a super-URI of any of the given URIs is given.

HTTPPasswordMgr. find_user_password ( realm , authuri ) ¶

Get user/password for given realm and URI, if any. This method will return (None, None) if there is no matching user/password.

For HTTPPasswordMgrWithDefaultRealm 对象，领域 None will be searched if the given realm has no matching user/password.

20.6.8. AbstractBasicAuthHandler 对象 ¶

AbstractBasicAuthHandler. http_error_auth_reqed ( authreq , host , req , headers ) ¶

Handle an authentication request by getting a user/password pair, and re-trying the request. authreq should be the name of the header where the information about the realm is included in the request, host specifies the URL and path to authenticate for, req should be the (failed) Request object, and headers should be the error headers.

host is either an authority (e.g. "python.org" ) or a URL containing an authority component (e.g. "http://python.org/" ). In either case, the authority must not contain a userinfo component (so, "python.org" and "python.org:80" are fine, "joe:password@python.org" is not).

20.6.9. HTTPBasicAuthHandler 对象 ¶

HTTPBasicAuthHandler. http_error_401 ( req , fp , code , msg , hdrs ) ¶

Retry the request with authentication information, if available.

20.6.10. ProxyBasicAuthHandler 对象 ¶

ProxyBasicAuthHandler. http_error_407 ( req , fp , code , msg , hdrs ) ¶

Retry the request with authentication information, if available.

20.6.11. AbstractDigestAuthHandler 对象 ¶

AbstractDigestAuthHandler. http_error_auth_reqed ( authreq , host , req , headers ) ¶

authreq should be the name of the header where the information about the realm is included in the request, host should be the host to authenticate to, req should be the (failed) Request object, and headers should be the error headers.

20.6.12. HTTPDigestAuthHandler 对象 ¶

HTTPDigestAuthHandler. http_error_401 ( req , fp , code , msg , hdrs ) ¶

Retry the request with authentication information, if available.

20.6.13. ProxyDigestAuthHandler 对象 ¶

ProxyDigestAuthHandler. http_error_407 ( req , fp , code , msg , hdrs ) ¶

Retry the request with authentication information, if available.

20.6.14. HTTPHandler 对象 ¶

HTTPHandler. http_open ( req ) ¶

Send an HTTP request, which can be either GET or POST, depending on req.has_data() .

20.6.15. HTTPSHandler 对象 ¶

HTTPSHandler. https_open ( req ) ¶

Send an HTTPS request, which can be either GET or POST, depending on req.has_data() .

20.6.16. FileHandler 对象 ¶

FileHandler. file_open ( req ) ¶

打开本地文件，若没有主机名，或主机名为 'localhost' . Change the protocol to ftp otherwise, and retry opening it using parent .

20.6.17. FTPHandler 对象 ¶

FTPHandler. ftp_open ( req ) ¶

打开 FTP (文件传输协议) 文件指示通过 req 。登录始终使用空用户名和口令完成。

20.6.18. CacheFTPHandler 对象 ¶

CacheFTPHandler 对象是 FTPHandler 对象，具有以下额外方法：

CacheFTPHandler. setTimeout ( t ) ¶

把连接超时设为 t 秒。

CacheFTPHandler. setMaxConns ( m ) ¶

把缓存的最大连接数设为 m .

20.6.19. UnknownHandler 对象 ¶

UnknownHandler. unknown_open ( ) ¶

引发 URLError 异常。

20.6.20. HTTPErrorProcessor 对象 ¶

2.4 版新增。

HTTPErrorProcessor. http_response ( ) ¶

处理 HTTP 错误响应。

对于 200 错误代码，响应对象被立即返回。

For non-200 error codes, this simply passes the job on to the protocol_error_code 处理程序方法，凭借 OpenerDirector.error() . Eventually, urllib2.HTTPDefaultErrorHandler 将引发 HTTPError 若没有其它处理程序处理错误。

HTTPErrorProcessor. https_response ( ) ¶

处理 HTTPS 错误响应。

行为如同 http_response() .

20.6.21. 范例 ¶

除以下范例外，更多范例给出于 如何使用 urllib2 抓取 Internet 资源 .

This example gets the python.org main page and displays the first 100 bytes of it:

>>> import urllib2
>>> f = urllib2.urlopen('http://www.python.org/')
>>> print f.read(100)
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<?xml-stylesheet href="./css/ht2html
						

Here we are sending a data-stream to the stdin of a CGI and reading the data it returns to us. Note that this example will only work when the Python installation supports SSL.

>>> import urllib2
>>> req = urllib2.Request(url='https://localhost/cgi-bin/test.cgi',
...                       data='This data is passed to stdin of the CGI')
>>> f = urllib2.urlopen(req)
>>> print f.read()
Got Data: "This data is passed to stdin of the CGI"
						

The code for the sample CGI used in the above example is:

#!/usr/bin/env python
import sys
data = sys.stdin.read()
print 'Content-type: text-plain\n\nGot Data: "%s"' % data
						

Use of Basic HTTP Authentication:

import urllib2
# Create an OpenerDirector with support for Basic HTTP Authentication...
auth_handler = urllib2.HTTPBasicAuthHandler()
auth_handler.add_password(realm='PDQ Application',
                          uri='https://mahler:8092/site-updates.py',
                          user='klem',
                          passwd='kadidd!ehopper')
opener = urllib2.build_opener(auth_handler)
# ...and install it globally so it can be used with urlopen.
urllib2.install_opener(opener)
urllib2.urlopen('http://www.example.com/login.html')
						

build_opener() provides many handlers by default, including a ProxyHandler 。默认情况下， ProxyHandler uses the environment variables named <scheme>_proxy ，其中 <scheme> is the URL scheme involved. For example, the http_proxy environment variable is read to obtain the HTTP proxy’s URL.

This example replaces the default ProxyHandler with one that uses programmatically-supplied proxy URLs, and adds proxy authorization support with ProxyBasicAuthHandler .

proxy_handler = urllib2.ProxyHandler({'http': 'http://www.example.com:3128/'})
proxy_auth_handler = urllib2.ProxyBasicAuthHandler()
proxy_auth_handler.add_password('realm', 'host', 'username', 'password')
opener = urllib2.build_opener(proxy_handler, proxy_auth_handler)
# This time, rather than install the OpenerDirector, we use it directly:
opener.open('http://www.example.com/login.html')
						

添加 HTTP 头：

使用 headers 自变量到 Request 构造函数，或：

import urllib2
req = urllib2.Request('http://www.example.com/')
req.add_header('Referer', 'http://www.python.org/')
# Customize the default User-Agent header value:
req.add_header('User-Agent', 'urllib-example/0.1 (Contact: . . .)')
r = urllib2.urlopen(req)
						

OpenerDirector 自动添加 User-Agent 头到每个 Request 。要改变这：

import urllib2
opener = urllib2.build_opener()
opener.addheaders = [('User-agent', 'Mozilla/5.0')]
opener.open('http://www.example.com/')
						

Also, remember that a few standard headers ( Content-Length , Content-Type and Host ) are added when the Request 被传递给 urlopen() (或 OpenerDirector.open() ).

内容表

• 20.6. urllib2 — 用于打开 URL 的可扩展库
  • 20.6.1. Request Objects
  • 20.6.2. OpenerDirector Objects
  • 20.6.3. BaseHandler Objects
  • 20.6.4. HTTPRedirectHandler Objects
  • 20.6.5. HTTPCookieProcessor Objects
  • 20.6.6. ProxyHandler Objects
  • 20.6.7. HTTPPasswordMgr Objects
  • 20.6.8. AbstractBasicAuthHandler Objects
  • 20.6.9. HTTPBasicAuthHandler Objects
  • 20.6.10. ProxyBasicAuthHandler Objects
  • 20.6.11. AbstractDigestAuthHandler Objects
  • 20.6.12. HTTPDigestAuthHandler Objects
  • 20.6.13. ProxyDigestAuthHandler Objects
  • 20.6.14. HTTPHandler Objects
  • 20.6.15. HTTPSHandler Objects
  • 20.6.16. FileHandler Objects
  • 20.6.17. FTPHandler Objects
  • 20.6.18. CacheFTPHandler Objects
  • 20.6.19. UnknownHandler Objects
  • 20.6.20. HTTPErrorProcessor Objects
  • 20.6.21. Examples

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