Django basics

First, install and use

Download and install
- Command line: pip3 install django == 1.11.21
- pycharm
Create a project
- Command Line:
  - Find a folder to store the project file, open a terminal:
  - django-admin startproject Project Name
  - Project Directory
- pycahrm
start up
- Command Line
  - Switch to the root directory of the project under manage.py
  - python36 manage.py runserver —— 127.0.0.1:80`
  - python36 manage.py runserver 80——127.0.0.1:80
  - python36 manage.py runserver 0.0.0.0:80——0.0.0.0:80
- pycharm: green triangle starting point can be configured

Simple to use

Example: Returns the specified HTML file

# In urls.py the 
# imported 
from django.shortcuts Import the HttpResponse, the render 
# function 
DEF index (Request):
     # return the HttpResponse ( 'index') 
    return the render (Request, ' index.html ' ) 
# URL and the corresponding function relationship between 
the urlpatterns = [ 
    URL (R & lt ' ^ ADMIN / ' , admin.site.urls), 
    URL (R & lt ' ^ index / ' , index), 
]

Second, static files

Configuration

Set in the settings.py

= STATIC_URL ' / static / '           # Aliases 
STATICFILES_DIRS = [             # Set the file path, can be provided a plurality of 
    the os.path.join (base_dir, ' static1 ' ), 
    the os.path.join (base_dir, ' static ' ), 
    the os.path .join (base_dir, ' static2 ' ), 
]

use
- Add an alias before the path: / static /
- Multiple file paths, but also use the same alias, not the file name
- If the path after the same alias name, in order to find a list of STATICFILES_DIRS
```
< Link the rel = "this stylesheet" the href = "/ static / CSS / the login.css" >          {# #} beginning Aliases 
```

Third, the simple login example

form data form to submit questions to note:
- Address filed: action = "", the requested mode: method = "post"
- All attributes have a name input box, such as the name = "username"
- There is a input box type = "submit" or there is a button
Submit post request, since Django has a csrf check, all requests will be problems
- Solution: The settings in MIDDLEWARE of 'django.middleware.csrf.CsrfViewMiddleware' commented

Redirect

导入：from django.shortcuts import redirect

# Used in the function, for example, 
return the redirect ( ' / index / ' )       # Parameters: url Path 
# Note: must be preceded by /, representatives from the root url splicing, or would have been spliced back current url

from django.shortcuts Import the HttpResponse, the render, the redirect 
DEF index (Request):
     # return the HttpResponse ( 'index') 
    return the render (Request, ' index.html ' ) 
DEF Login (Request):
     IF request.method == ' POST ' :
         # acquire books form submitted form 
        username = request.POST [ ' username ' ] 
        password = request.POST [ ' password ' ]
         # authentication username and password 
        ifmodels.User.objects.filter (username = username, password = password):
             # authentication is successful jump to the index page 
            # return the redirect ( 'https://www.baidu.com/') 
            return the redirect ( ' / index / ' )
         # unsuccessful login again 
    return the render (Request, ' the login.html ' ) 
the urlpatterns = [ 
    URL (R & lt ' ^ ADMIN / ' , admin.site.urls), 
    URL (R & lt ' ^ index / ' , views.index) , 
    URL (R & lt ' ^ Login / ' , views.login), 
]

Examples

Four, app

Creating app
- Command line: python manage.py startapp app name
- pycharm: tools -> run manage.py task -> enter the command: startapp app name

Settings.py provided in Example: app named app01

= INSTALLED_APPS [ 
    ... 
    ' app01 ' ,
     ' app01.apps.App01Config ' ,        # recommended wording 
]

app files
- migrations: Migrating store file
- admin.py:Django provides background management tool
- app.py: information related to the app
- models.py: ORM with related content
- views.py: view, write function

Fifth, use the MySQL process

Create a MySQL database: create database day53;

In settings.py set, Django connect to the MySQL database:

= DATABASES {
     ' default ' : {
         ' ENGINE ' : ' django.db.backends.mysql ' ,       # engine 
        ' NAME ' : ' day53 ' ,                          # database name 
        ' the HOST ' : ' 127.0.0.1 ' ,                      # IP address 
        ' PORT ' : 3306                             # port 
        ' the USER ' : 'the root ' ,                           # users 
        ' PASSWORD ' : ' 123 '                         # password 
    } 
}

Written and settings, init py files in the same directory in which:
```
import pymysql
pymysql.install_as_MySQLdb()
```

Create a table (written under the app models.py class):

from django.db import models

class User(models.Model):
    username = models.CharField(max_length=32)       # username varchar(32)
    password = models.CharField(max_length=32)       # username varchar(32)

Run the database migration:
- python manage.py makemigrations: model.py registered under detect each app, record changes of record model
- python manage.py migrate: synchronized recording changes to the database

Six, MVC and MTV

MVC
- M: model model - and interact with the database
- V: view view - HTML
- C: controller Controller - transfer instruction dispatch logic operations
MTV：
- M: model model ORM - and interact with the database
- T: tempalte Template - HTML
- V: view view - business logic function
djando is MTV mode

First, install and use

Second, static files

Third, the simple login example

Four, app

Fifth, use the MySQL process

Six, MVC and MTV

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