基于django2.2的网页构建

1. 安装django

   pip install django==2.2
   

2. 建一个在线商城的项目

   django-admin startproject pyshop
   

3. 启动项目

   python manage.py runserver
   

4. 页面访问效果 http://127.0.0.1:8000

   

5. 建议一个项目的app 产品 products

   django-admin startapp products
   

6. 在app的 views 里面写一下 请求页面 比如 http://127.0.0.1:8000/products

   from django.shortcuts import render
   from django.http import HttpResponse
   def index(request):
       return HttpResponse('HelloWorld')
   

7. 为了让 products能够访问 需要在app的urls(需要自己建) 及 项目的urls配置urlpatterns

   app的url配置：

   from django.urls import path
   from . import views
   urlpatterns = [
       path('', views.index),
   ]
   

   项目的url配置 他要包括app的url 组合起来用

   from django.contrib import admin
   from django.urls import path, include
   urlpatterns = [
       path('admin/', admin.site.urls),
       path('products/', include('products.urls')),
   ]
   

8. 展示效果http://127.0.0.1:8000/products/

   

9. 模型 对product 进行模型设计 实际上就是建表（python会按照模型建好的自己建表）

   from django.db import models
   # Create your models here.
   class Product(models.Model):
       name = models.CharField(max_length=255)
       price = models.FloatField()
       stock = models.IntegerField()
       image_url = models.CharField(max_length=2083)
   

10. 在setting 加上 app的配置

    INSTALLED_APPS = [
        'django.contrib.admin',
        'django.contrib.auth',
        'django.contrib.contenttypes',
        'django.contrib.sessions',
        'django.contrib.messages',
        'django.contrib.staticfiles',
        'products.apps.ProductsConfig',
    ]
    

11. 创建product的model

    python manage.py makemigrations
    

    (venv) D:\PyShop>python manage.py makemigrations
    Migrations for 'products':
      products\migrations\0001_initial.py
        - Create model Product
    (venv) D:\PyShop>
    

    初始化的文件放在这里 products\migrations\0001_initial.py

12. 根据生产的 初始化文件建表

    python manage.py migrate
    

    (venv) D:\PyShop>python manage.py migrate
    Operations to perform:
      Apply all migrations: admin, auth, contenttypes, products, sessions
    Running migrations:
      Applying contenttypes.0001_initial... OK
      Applying auth.0001_initial... OK
      Applying admin.0001_initial... OK
      Applying admin.0002_logentry_remove_auto_add... OK
      Applying admin.0003_logentry_add_action_flag_choices... OK
      Applying contenttypes.0002_remove_content_type_name... OK
      Applying auth.0002_alter_permission_name_max_length... OK
      Applying auth.0003_alter_user_email_max_length... OK
      Applying auth.0004_alter_user_username_opts... OK
      Applying auth.0005_alter_user_last_login_null... OK
      Applying auth.0006_require_contenttypes_0002... OK
      Applying auth.0007_alter_validators_add_error_messages... OK
      Applying auth.0008_alter_user_username_max_length... OK
      Applying auth.0009_alter_user_last_name_max_length... OK
      Applying auth.0010_alter_group_name_max_length... OK
      Applying auth.0011_update_proxy_permissions... OK
      Applying products.0001_initial... OK
      Applying sessions.0001_initial... OK
    (venv) D:\PyShop>
    

13. 类似的 再建一个 offer的模型 包含 优惠券的代码 描述 和折扣

    class Offer(models.Model):
        code = models.CharField(max_length=10)
        description = models.CharField(max_length=256)
        discount = models.FloatField()
    同样去做迁移变化
    (venv) D:\PyShop>python manage.py makemigrations
    Migrations for 'products':
      products\migrations\0002_offer.py
        - Create model Offer
    (venv) D:\PyShop>
    再去生成表
    (venv) D:\PyShop>python manage.py migrate
    Operations to perform:
      Apply all migrations: admin, auth, contenttypes, products, sessions
    Running migrations:
      Applying products.0002_offer... OK
    (venv) D:\PyShop>
    

14. 创建超级管理员 admin

    (venv) D:\PyShop>python manage.py createsuperuser
    Username (leave blank to use 'work1'): admin
    Email address: dfwlai@163.com
    Password:
    Password (again):
    The password is too similar to the username.
    This password is too short. It must contain at least 8 characters.
    This password is too common.
    Bypass password validation and create user anyway? [y/N]: y
    Superuser created successfully.
    (venv) D:\PyShop>
    

15. 在admin.py中注册我们的模型

    from django.contrib import admin
    from .models import Product
    # Register your models here.
    admin.site.register(Product)
    

    admin页面会显示如下

    

16. 可以手动增加一个产品 橘子

    

17. 展示效果如下

    

18. 这个时候我们改一下 让产品字段按列表展出

    from django.contrib import admin
    from .models import Product
    # Register your models here.
    class ProductAdmin(admin.ModelAdmin):
        list_display = ('name','price','stock')
    admin.site.register(Product,ProductAdmin)
    

    效果

    

环境：python3.7.4 django 2.2

部署过程中遇到的问题：

1、报错：

　　File "D:\Python\Python37-32\lib\site-packages\django\views\debug.py", line 332, in get_traceback_html

　　t = DEBUG_ENGINE.from_string(fh.read())　　

　　UnicodeDecodeError: 'gbk' codec can't decode byte 0xa6 in position 9737: illegal multibyte sequence

解决：

　　打开django/views下的debug.py文件，转到line331行：

　　　with Path(CURRENT_DIR, 'templates', 'technical_500.html').open() as fh

　　将其改成：

　　　　with Path(CURRENT_DIR, 'templates', 'technical_500.html').open(encoding="utf-8") as fh

就成功了。

3、django.core.exceptions.ImproperlyConfigured: Error loading MySQLdb module.

Did you install mysqlclient?

pip install PyMySQL pymsql 已经不用了

pip install mysqlclient 安装mysqlclient

wiki：

使用mysql 来当数据库

1、首先默认的setting的数据库配置
DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.sqlite3',
        'NAME': os.path.join(BASE_DIR, 'db.sqlite3'),
    }
}
改为:  其中lzy  是database名字 我的本地库 root没有密码
DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql',
        'NAME': 'lzy',
        'HOST': '127.0.0.1',
        'PORT': 3306,
        'USER': 'root',
        'PASSWORD': '',
    }
}