我正在 Django 中编写一个 URL 缩短器应用程序。我想检查一个 URL 是否过期（URL 仅在 3 小时内有效）。下面是我的models.py，但它不工作我收到错误can't subtract datetime object
import uuid
import base64
import datetime
from django.db import models
from django.contrib import admin
#------------------------------------------------------------------------------
def _generateShortUrl():
"""
This function will generate base64 encoded id
"""
return base64.urlsafe_b64encode(uuid.uuid1().bytes)[:6]
class link(models.Model):
"""
This is a link class
"""
link = models.URLField() # To store user entered URL
hits = models.IntegerField(default=0) # How many hits for particular URL
last_used = models.DateTimeField(auto_now=True) # When URL is last used
short_url = models.CharField(max_length=6,unique=True) # base64 URL encoded id
def linkValidate(self):
timediff = datetime.datetime.now() - self.last_used
return timediff.min
def save(self, *args, **kwargs):
"""
Custom Save method for link model
"""
self.short_url = _generateShortUrl()
super(link, self).save(*args, **kwargs)
class user_info(models.Model):
"""
This is a user_info class
"""
user_agent = models.TextField() # Stores user_agent name used by user
user_ip = models.ManyToManyField(link) # Stores user's IP
def userIP(self):
"""Method to return tags related to store"""
return ','.join([t.link for t in self.link.all()])
#------------------------------------------------------------------------------
class linkAdmin(admin.ModelAdmin):
"""
link admin class
"""
list_display = ('link','hits','short_url','last_used',
'linkValidate')
ordering = ('hits',)
class userInfoAdmin(admin.ModelAdmin):
"""
user_info admin class
"""
list_display = ('user_agent','userIP')
#------------------------------------------------------------------------------
admin.site.register(link,linkAdmin)
admin.site.register(user_info,userInfoAdmin)
有人可以帮帮我吗。