【转帖+改造】django HTTP Request 的调用层次
from http://kasicass.blog.163.com/blog/static/3956192009510115226144/

django.core.management.base.py, commands 的基类，定义了几个基础接口
django.core.management.[commands], 里面实现了 startproject, runserver 等所有的 commands
django.core.management.__init__.py 中的 execute_manager() 是所有逻辑的入口。

python manager.py runserver ip:port ==>  django.core.management.__init__.py    django.core.management.commands.runserver.py      django.core.servers.basehttp.run()        httpd = WSGIServer(server_address, WSGIRequestHandler)        httpd.set_app(wsgi_handler)  # wsgi_handler = AdminMediaHandler(WSGIHandler(), path)        httpd.serve_forever()        # django.core.handlers.wsgi.WSGIHandlerhttp request =>  django.core.servers.basehttp.WSGIRequestHandler.handle()    django.core.servers.basehttp.ServerHandler.run()      django.core.servers.basehttp.AdminMediaHandler.__call__()        django.core.handlers.wsgi.WSGIHandler.__call__()          request = self.request_class(environ)     【1】          response = self.get_response(request)      【2】            django.core.handlers.base.BaseHandler.get_response()              resolver = urlresolvers.RegexURLResolver(r'^/', urlconf)              callback, callback_args, callback_kwargs = resolver.resolve(request.path_info)              response = callback(request, *callback_args, **callback_kwargs)    django.core.servers.basehttp.ServerHandler.run(), response 会被一路 return，到达这里后，拼接，再发回给浏览器。

我们的小程序 helloworld.index() 就是上面的 callback 函数。
-------------------------------------------------
# urls.py

urlpatterns = patterns('',    (r'^hello/$', 'foobar.helloworld.index'),)

-------------------------------------------------
# helloworld.py

from django.http import HttpResponsedef index(request):    return HttpResponse("Hello Django!")

-------------------------------------------------

WSGI 是啥，看：
http://cvs.woodpecker.org.cn/svn/woodpecker/pureprolog/trunk/essay/wsgiinto/wsgi_into.html
http://wiki.python.org/moin/WSGIImplementations


==================================================================================
//我的注释：奇怪吗，在上面生成response的过程当中，又再次生成了request，看上面的【1】，原因在于：我们对request对象当中进行的一些参数设置，要反馈到response当中去，比如cookie和session，这也不难理解为什么下面这样的代码，把我们设置的session 给回传给客户端了

 def login(request):       m = Member.objects.get(username=request.POST['username'])      if m.password == request.POST['password']:          request.session['member_id'] = m.id          return HttpResponse("You're logged in.")      else:          return HttpResponse("Your username and password didn't match.") 

via http://docs.djangoproject.com/en/dev/topics/http/sessions/