Django学习笔记第五篇--实战练习一--查询数据库并操作cookie

一、启动项目：

 django-admin start mysite1
 cd mysite1
 python manage.py startapp loginapp

根据上文敲命令就可以创建好了一个项目结构，之后就是修改配置文件，这里使用的数据库是MySQL的。

二、修改配置文件：

settings.py

 """
 Django settings for mysite1 project.

 Generated by 'django-admin startproject' using Django 1.8.

 For more information on this file, see
 https://docs.djangoproject.com/en/1.8/topics/settings/

 For the full list of settings and their values, see
 https://docs.djangoproject.com/en/1.8/ref/settings/
 """

 # Build paths inside the project like this: os.path.join(BASE_DIR, ...)
 import os

 BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))

 # Quick-start development settings - unsuitable for production
 # See https://docs.djangoproject.com/en/1.8/howto/deployment/checklist/

 # SECURITY WARNING: keep the secret key used in production secret!
 SECRET_KEY = 'u-=+xrj*5cr+z92==pmlct&c2ta+7o8ia8_y!(ne^*538_afr1'

 # SECURITY WARNING: don't run with debug turned on in production!
 DEBUG = True

 ALLOWED_HOSTS = []

 # Application definition

 INSTALLED_APPS = (
     'django.contrib.admin',
     'django.contrib.auth',
     'django.contrib.contenttypes',
     'django.contrib.sessions',
     'django.contrib.messages',
     'django.contrib.staticfiles',
     'loginapp'
 )

 MIDDLEWARE_CLASSES = (
     'django.contrib.sessions.middleware.SessionMiddleware',
     'django.middleware.common.CommonMiddleware',
     'django.middleware.csrf.CsrfViewMiddleware',
     'django.contrib.auth.middleware.AuthenticationMiddleware',
     'django.contrib.auth.middleware.SessionAuthenticationMiddleware',
     'django.contrib.messages.middleware.MessageMiddleware',
     'django.middleware.clickjacking.XFrameOptionsMiddleware',
     'django.middleware.security.SecurityMiddleware',
 )

 ROOT_URLCONF = 'mysite1.urls'

 TEMPLATES = [
     {
         'BACKEND': 'django.template.backends.django.DjangoTemplates',
         'DIRS': [],
         'APP_DIRS': True,
         'OPTIONS': {
             'context_processors': [
                 'django.template.context_processors.debug',
                 'django.template.context_processors.request',
                 'django.contrib.auth.context_processors.auth',
                 'django.contrib.messages.context_processors.messages',
             ],
         },
     },
 ]

 WSGI_APPLICATION = 'mysite1.wsgi.application'

 # Database
 # https://docs.djangoproject.com/en/1.8/ref/settings/#databases

 DATABASES = {
     'default': {
         'ENGINE': 'django.db.backends.mysql',
         'NAME': 'mysite1',
         'USER': 'root',
         'HOST': '127.0.0.1',
         'PORT': '',
     }
 }

 # Internationalization
 # https://docs.djangoproject.com/en/1.8/topics/i18n/

 LANGUAGE_CODE = 'en-us'

 TIME_ZONE = 'UTC'

 USE_I18N = True

 USE_L10N = True

 USE_TZ = True

 # Static files (CSS, JavaScript, Images)
 # https://docs.djangoproject.com/en/1.8/howto/static-files/

 STATIC_URL = '/static/'

三、创建数据库：

 mysql -h 127.0.0.1 -u root
 create database mysite1
 exit

然后编辑models.py文件：

 from django.db import models

 # Create your models here.
 class account(models.Model):
     username = models.CharField(max_length=20)
     password = models.CharField(max_length=256)

然后选择创建数据库表结构

 $ python manage.py migrate   # 创建表结构
 $ python manage.py makemigrations loginapp  # 让 Django 知道我们的模型有一些变更
 $ python manage.py migrate loginapp   # 创建表结构

四、编写urls.py文件：

 from django.conf.urls import include, url
 from django.contrib import admin
 from loginapp import views

 urlpatterns = [
     # Examples:
     # url(r'^$', 'mysite1.views.home', name='home'),
     # url(r'^blog/', include('blog.urls')),

     url(r'^admin/', include(admin.site.urls)),
     url(r'^login/', 'loginapp.views.login'),
     url(r'^main/', 'loginapp.views.main'),
     url(r'^logout/', 'loginapp.views.logout'),
 ]

五、最重要的视图函数到了：

views.py

 # -*- coding:utf-8 -*-
 import hashlib
 from django.shortcuts import render
 from django.http import HttpResponse
 from models import account
 # Create your views here.
 def get_md5(text):
     md5 = hashlib.md5()
     d5.update(text)
     return md5.hexdigest()

 def login(request):
     user = request.GET["user"]
     pswd = request.GET["pswd"]
     #pswd = get_md5(pswd)
     result = account.objects.get(username=user)
     try:
         if pswd == result.password:
             response = HttpResponse("Welcome %s, Login Success!"%user)
             response.set_cookie("login_name",user)
             response.set_cookie("login_code",1)
             return response
         else:
             return HttpResponse("Sorry,Login Failed!")
     except Excception,ex:
         return HttpResponse("Sorry,Login Failed!")

 def main(request):
     if "login_code" in request.COOKIES:
         logincode = request.COOKIES["login_code"]
         print logincode
         print type(logincode)
         if logincode == "":
             return HttpResponse("Yes , sir!")
         else:
             return HttpResponse("Sorry , sir!")

 def logout(request):
     user = request.GET["user"]
     if "login_name" in request.COOKIES:
         if user == request.COOKIES["login_name"]:
             response = HttpResponse("ByeBye!")
             response.set_cookie("login_code",0)
             return response
         else:
             return HttpResponse("Sorry User Error!")
     else:
         return HttpResponse("Sorry User Error!")

六、总结：

1、数据库的对象应该是from modles.py import classname 这里就是数据库对象了，然后就是classname.objects.get或者其他操作；

2、get方法获取的是符合条件的数据的一项，是一个数据实例，其属性使用ret.name方式调用；

3、读写cookie，cookie在request.COOKIES中，字典结构，写的事后麻烦一些，需要response = HttpResponse等一类返回响应对象的函数的返回值。然后使用response.ser_cookie(key,value)方式设置，最后return response返回；

 from models import account
 #create a new user
 account.objects.create(username=user,password=pswd)
 ##or
 object = account(username=user,password=pswd)
 object.save()

 #delete a user
 account.objects.filter(username=user).delete()

 #update a user
 account.objects.filter(username=user).update(password=pswd)
 ##or
 object = account.objects.get(username=user)
 object.password = pswd
 object.save()

 #query for a user
 account.objects.get(username=user,password=pswd)
 ##or
 account.objects.all()
 ##or
 account.objects.all().values(username)
 account.objects.all().values_list(username,password)