enkel/batteri/session.py

   1 # This file is part of the Enkel web programming library.
   2 #
   3 # Copyright (C) 2007 Espen Angell Kristiansen (espeak@users.sourceforge.net)
   4 #
   5 # This program is free software; you can redistribute it and/or
   6 # modify it under the terms of the GNU General Public License
   7 # as published by the Free Software Foundation; either version 2
   8 # of the License, or (at your option) any later version.
   9 #
  10 # This program is distributed in the hope that it will be useful,
  11 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 # GNU General Public License for more details.
  14 #
  15 # You should have received a copy of the GNU General Public License
  16 # along with this program; if not, write to the Free Software
  17 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  18
  19 from enkel.cookie import Cookie, get_cookies
  20 from enkel.session.backend import NoSuchSessionError
  21
  22
  23 class StartResponseWrapper(object):
  24         """ Used by SessionMiddleware. """
  25         def __init__(self, start_response, cookie):
  26                 self.start_response = start_response
  27                 self.cookie = cookie
  28
  29         def __call__(self, status, headers, exc_info=None):
  30                 headers.append(self.cookie.get_httpheader())
  31                 return self.start_response(status, headers, exc_info)
  32
  33
  34 class SessionMiddleware(object):
  35         """ A session middleware.
  36
  37         Test/Example
  38         ============
  39                 >>> from enkel.wansgli.apptester import AppTester
  40                 >>> from enkel.session.memory import MemorySession
  41
  42                 >>> def myapp(env, start_response):
  43                 ...     start_response("200 OK", [("Content-type", "text/plain")])
  44                 ...     session = env["enkel.session"]
  45                 ...     if "num" in session:
  46                 ...             session["num"] += 1
  47                 ...     else:
  48                 ...             session["num"] = 0
  49                 ...     return ["This is call number %(num)d to this app" % session]
  50
  51                 >>> class MyBackend(MemorySession):
  52                 ...     def generate_sid(self):
  53                 ...             return "xxAb"
  54
  55                 >>> b = MyBackend()
  56                 >>> sessionapp = SessionMiddleware(myapp, b)
  57
  58                 >>> AppTester(sessionapp).run_get().body
  59                 'This is call number 0 to this app'
  60
  61                 >>> t = AppTester(sessionapp)
  62                 >>> t.set_env("HTTP_COOKIE", "sid=xxAb")
  63                 >>> t.run_get().body
  64                 'This is call number 1 to this app'
  65
  66         @cvar ENV_KEY: The environ key used to contain the session.
  67         """
  68         ENV_KEY = "enkel.session"
  69         def __init__(self, app, backend, cookiename="sid",
  70                                 cookiedomain=None, cookiepath="/"):
  71                 """
  72                 @param app: A WSGI application.
  73                 @param backend: A session backend following the
  74                                 L{enkel.session.backend.SessionBackend} interface.
  75                 @param cookiename: The name of the session cookie.
  76                 @param cookiedomain: See L{enkel.cookie.Cookie.domain}.
  77                 @param cookiepath: See L{enkel.cookie.Cookie.path}.
  78                 """
  79                 self.app = app
  80                 self.backend = backend
  81                 self.cookiename = cookiename
  82                 self.cookiedomain = cookiedomain
  83                 self.cookiepath = cookiepath
  84
  85         def __call__(self, env, start_response):
  86
  87                 # import info from cookie
  88                 cookies = get_cookies(env)
  89                 session = None
  90                 if cookies and self.cookiename in cookies:
  91                         try:
  92                                 sid = cookies[self.cookiename]
  93                         except KeyError:
  94                                 pass
  95                         else:
  96                                 try:
  97                                         session = self.backend.load(sid)
  98                                 except NoSuchSessionError:
  99                                         pass
 100
 101                 if session == None:
 102                         session = dict()
 103                         sid = self.backend.generate_sid()
 104                 env[self.ENV_KEY] = session
 105
 106                 # create new cookie
 107                 cookie = Cookie(self.cookiename, sid)
 108                 cookie.path = self.cookiepath
 109                 cookie.domain = self.cookiedomain
 110                 cookie.set_timeout(self.backend.timeout)
 111
 112                 # run app
 113                 sr = StartResponseWrapper(start_response, cookie)
 114                 for buf in self.app(env, sr):
 115                         yield buf
 116                 self.backend.save(sid, session)
 117
 118
 119
 120 def suite():
 121         import doctest
 122         return doctest.DocTestSuite()
 123
 124 if __name__ == "__main__":
 125         from enkel.wansgli.testhelpers import run_suite
 126         run_suite(suite())