响应中的URLLIB2多集cookie头

根据 urllib2 docs , the .headers 结果url对象的属性是 httplib.HTTPMessage (至少在python文档中,它似乎是未记录的)。

然而,

help(httplib.HTTPMessage)
...

If multiple header fields with the same name occur, they are combined
according to the rules in RFC 2616 sec 4.2:

Appending each subsequent field-value to the first, each separated
by a comma. The order in which header fields with the same field-name
are received is significant to the interpretation of the combined
field value.

因此,如果您访问U.headers['set-cookie'],您应该得到一个set cookie头,其值由逗号分隔。

事实上,情况似乎是这样的。

import httplib
from StringIO import StringIO

msg = \
"""Set-Cookie: Foo
Set-Cookie: Bar
Set-Cookie: Baz

This is the message"""

msg = StringIO(msg)

msg = httplib.HTTPMessage(msg)

assert msg['Set-Cookie'] == 'Foo, Bar, Baz'

set-cookie 不过不同。来自RFC 6265:

源服务器不应将多个set cookie头字段折叠到 一个标题字段。折叠HTTP头的常见机制 字段(即[rfc2616]中定义的字段)可能会更改 设置cookie头字段,因为使用了%x2c(“,”)字符 将cookie设置为与这种折叠冲突的方式。

从理论上讲,这看起来像一个bug。