django中確定會話的年齡

Question

如何確定django中會話對象的年齡？

Answer 1

好的，這是我想出的。好多了。我認爲這是作爲使用Session對象post_save便宜是會得到：

from django.db import models 
from people.models import Member 
from django.contrib.sessions.models import Session 
from django.contrib.sessions.backends.db import SessionStore 


from django.db.models import * 
from django.db.models.signals import post_save, pre_delete, post_init 
from datetime import datetime 

class SessionInfo(models.Model): 
    #note: a OneToOneField with the name 'session' has been added as part of the inheritance 
    created = models.DateTimeField(auto_now_add=True) #joined field is auto initialized with creation time 
    session = models.OneToOneField(Session) 
    def age(self): 
     return (datetime.now() - self.created) 


def session_create_listener(instance, **kwargs): 
    store = SessionStore(session_key=instance.session_key) 

    if '_auth_user_id' in store: 
     try: 
      instance.sessioninfo 
     except SessionInfo.DoesNotExist: 
      sessioninfo = SessionInfo(session=instance) 
      sessioninfo.save()   

post_save.connect(session_create_listener, sender=Session) 

Answer 2

您需要掛接來自django.contrib.sessions.models.Session的post_init信號，以通知會話開始（或結束），然後將該信息保存到您自己的應用程序中的模型。例如

from django.contrib.sessions.models import Session 
from django.db.models import * 
from django.db.models.signals import post_init, pre_delete 
from django.dispatch import receiver 
from datetime import datetime 

class SessionTimer(Session): 
    #note: a OneToOneField with the name 'session' has been added as part of the inheritance 
    created = DateTimeField(auto_now_add=True) #joined field is auto initialized with creation time 
    def age(self): 
     return (datetime.now() - self.created) 

@receiver(post_init, sender=Session) 
def session_create_listener(instance, **kwargs): 
    created_session = instance 
    timer_entry = SessionTimer(session=created_session) 
    timer_entry.save() 

@receiver(pre_delete, sender=Session) 
def session_destroy_listener(instance, **kwargs): 
    SessionTimer.objects.get(session=instance).delete() # short version 

因此，當你需要知道一個會話的年齡，使用session.sessiontimer.age()。這將返回一個表示會話年齡的TimeDelta對象。

Answer 3

這是我最終做的，而不是托馬斯的建議。請注意，我拒絕使用接收器裝飾器，以便它在1.3之前仍然有效。

（這需要嚴肅的糾正）。

from django.db import models 
from people.models import Member 
from django.contrib.sessions.models import Session 
from django.contrib.sessions.backends.db import SessionStore 


from django.db.models import * 
from django.db.models.signals import post_save, pre_delete, post_init 
#from django.dispatch import receiver 
from datetime import datetime 

class SessionInfo(models.Model): 
    #note: a OneToOneField with the name 'session' has been added as part of the inheritance 
    created = models.DateTimeField(auto_now_add=True) #joined field is auto initialized with creation time 
    session = models.OneToOneField(Session) 
    def age(self): 
     return (datetime.now() - self.created) 


def session_create_listener(instance, **kwargs): 
    store = SessionStore(session_key=instance.session_key) 

    if '_auth_user_id' in store: 
     try: 
      sessioninfo = SessionInfo.objects.get(session=instance) 
     except SessionInfo.DoesNotExist: 
      sessioninfo = SessionInfo(session=instance) 
      sessioninfo.save() 
      store['anonymous'] = False 
      store.save() 
    else: 
     try: 
      store['anonymous'] 
     except KeyError: 
      store['anonymous'] = True 
      store.save() 

post_save.connect(session_create_listener, sender=Session) 

我希望有人能爲我解決這個問題，因爲我無法相信這是最有效的方法。

首先，每當會話被修改時，這會增加兩個額外的數據庫命中（第一次嘗試：sessioninfo = SessionInfo.objects.get（session = instance））。

第一個顯然是在查找期間。第二次發生保存時，再次觸發整個過程。

怎麼辦？