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': '3306',
    }
}


# 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 == "1":
            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)