httplib.HTTPMessage
和classes[1]都email.message.Message
实现了 RFC822 标头解析的方法。不幸的是,它们有不同的实现[2],并且它们不提供相同级别的功能。
困扰我的一个例子是:
httplib.HTTPMessage
缺少 中get_filename
存在的方法email.Message
,该方法使您可以轻松地从Content-disposition: attachment; filename="fghi.xyz"
标题中检索文件名;httplib.HTTPMessage
hasgetparam
和methods 但 AFAIKgetplist
,parseplist
它们不是也不能在content-type
标头解析之外使用;email.Message
有一个通用的get_param
方法来解析任何带有参数的 RFC822 标头,例如content-disposition
或content-type
.
因此,我想要 in 的orget_filename
方法get_param
,但当然,我不能像标准库中那样修补它...... :-qemail.message.Message
httplib.HTTPMessage
httplib.HTTPMessage
最后,这里是装饰主题... :-)
我成功地创建了一个monkeypatch_http_message
函数来装饰httplib.HTTPMessage
我缺少的解析方法:
def monkeypatch_http_message(obj):
from email import utils
from email.message import (
_parseparam,
_unquotevalue,
)
cls = obj.__class__
# methods **copied** from email.message.Message source code
def _get_params_preserve(self, failobj, header): ...
def get_params(self, failobj=None, header='content-type',
unquote=True): ...
def get_param(self, param, failobj=None, header='content-type',
unquote=True): ...
def get_filename(self, failobj=None): ...
# monkeypatching httplib.Message
cls._get_params_preserve = _get_params_preserve
cls.get_params = get_params
cls.get_param = get_param
cls.get_filename = get_filename
现在我可以这样做:
import mechanize
from some.module import monkeypatch_http_message
browser = mechanize.Browser()
# in that form, browser.retrieve returns a temporary filename
# and an httplib.HTTPMessage instance
(tmp_filename, headers) = browser.retrieve(someurl)
# monkeypatch the httplib.HTTPMessage instance
monkeypatch_http_message(headers)
# yeah... my original filename, finally
filename = headers.get_filename()
这里的问题是我从源类中复制了装饰方法代码,我想避免这种情况。
所以,我尝试通过引用源方法来装饰:
def monkeypatch_http_message(obj):
from email import utils
from email.message import (
_parseparam,
_unquotevalue,
Message # XXX added
)
cls = obj.__class__
# monkeypatching httplib.Message
cls._get_params_preserve = Message._get_params_preserve
cls.get_params = Message.get_params
cls.get_param = Message.get_param
cls.get_filename = Message.get_filename
但这给了我:
Traceback (most recent call last):
File "client.py", line 224, in <module>
filename = headers.get_filename()
TypeError: unbound method get_filename() must be called with Message instance as first argument (got nothing instead)
我现在摸不着头脑......如何在不复制源方法的情况下装饰我的班级?
有什么建议么 ?:-)
问候,
乔治·马丁
在 Python 2.6 中。我不能在生产中使用 2.7 或 3.x。
httplib.HTTPMessage
继承自mimetools.Message
并且rfc822.Message
whileemail.Message
有自己的实现。