无cookie环境实现django会话

django的会话(session)中间件不提供类似j2ee和php中基于url重写的会话机制。
[quote]
Session IDs in URLs
The Django sessions framework is entirely, and solely, cookie-based. It does not fall back to putting session IDs in URLs as a last resort, as PHP does. This is an intentional design decision. Not only does that behavior make URLs ugly, it makes your site vulnerable to session-ID theft via the "Referer" header.
[/quote]

以下脚本通过中间件为django增添无cookie时的会话支持,在django1.0.2版本下工作正常, 注意，该中间件在setting模块MIDDLEWARE_CLASSES tuple中的位置必须优先于SessionMiddleware

#-*- coding:utf-8 -*-
from django.http  import  HttpResponseRedirect
import re,pdb

class CookielessSessionMiddleware(object):
    def __init__(self):

        self._re_links = re.compile(r'[^>]*?)href=["\'](?P[^"\']*?)(?P#\S+)?["\'](?P[^>]*?)>', re.I)

        self._re_forms = re.compile('', re.I)

    def _prepare_url(self, url):
        patt = None
        if url.find('?') == -1:
            patt = '%s?'
        else:
            patt = '%s&'
        return patt % (url,)

    def process_request(self, request):
        if not request.COOKIES.has_key('sessionid'):
            value = None
            if hasattr(request, 'POST') and request.POST.has_key('sessionid'):
                value = request.POST['sessionid']
            elif hasattr(request, 'GET') and request.GET.has_key('sessionid'):
                value = request.GET['sessionid']
            if value:
                request.COOKIES['sessionid'] = value        

    def process_response(self, request, response):

        if not request.path.startswith("/admin")  and response.cookies.has_key('sessionid'):
            try:
                sessionid = response.cookies['sessionid'].coded_value
                if type(response) is HttpResponseRedirect:

                    if not sessionid: sessionid = ""
                    redirect_url = [x[1] for x in response.items() if x[0] == "Location"][0]
                    redirect_url = self._prepare_url(redirect_url)
                    return HttpResponseRedirect('%ssessionid=%s' % (redirect_url,sessionid,)) 


                def new_url(m):
                    anchor_value = ""
                    if m.groupdict().get("anchor"): anchor_value = m.groupdict().get("anchor")
                    return_str = '' % \
                         (m.groupdict()['pre_href'],
                         self._prepare_url(m.groupdict()['in_href']),
                         sessionid,
                         anchor_value,
                         m.groupdict()['post_href'])
                    return return_str                                 
                response.content = self._re_links.sub(new_url, response.content)


                repl_form = '
' + \
                    ''
                repl_form = repl_form % (sessionid,)
                response.content = self._re_forms.sub(repl_form, response.content)

                return response
            except:

                return response
        else:
            return response