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The first experience of Django of Python full Stack Road Series

Django has to be said to be a very powerful full-stack framework in Python, and the entry is relatively simple, as long as you have learned the basic knowledge of Django, and then do one or two projects, not too small, and then you will find that in those small and beautiful frameworks, you will learn very quickly, because you have already learned and experienced the Web development process when you are learning Django. So there will be such a phenomenon, some novice friends in learning Flask, Tornado and other small and beautiful framework, many concepts do not quite understand, such as ORM, routing, etc., but you learn Django will not have this problem.

History of Django

Django grew up in real-world applications and was written by a web development team in Lawrence, Kansas. It was born in the fall of 2003, when Lawrence Journal-World newspaper programmers Adrian Holovaty and Simon Willison began to write programs in Python.

At that time, their World Online team produced and maintained several local news sites, and gradually developed in a fast-paced development environment peculiar to the press. These sites include LJWorld.com, Lawrence.com, and KUsports.com, and additional features required by journalists (or management) or the entire program can be quickly set up within a planned time, usually only a few days or hours. Therefore, Adrian and Simon have developed a time-saving network program development framework, which is the only way to complete the program before the deadline.

By the time the framework was developed in the summer of 2005, it had already been used to create a number of World Online sites. At that time, Jacob Kaplan-Moss on the World Online team decided to release the framework as open source software.

A few years from now, Django is a well-developed open source project with tens of thousands of users and contributors that has spread widely around the world. The two developers of the original World Online (Adrian and Jacob) are still in charge of Django, but its direction is more influenced by the community team.

Extracted from djangobook3

Django access proc

Before learning Django, let's first understand the access process of Django. This is very important, so that you can understand the whole workflow of Django. Of course, I have also drawn the picture, as shown in the following figure:

Explain how the above figure works. First, to create such an environment, you open Qzone, but you cannot directly access your space without entering your QQ account and password. At this time, you need to enter your account password to enter. Assuming that your account password output is correct, you will naturally enter Qzone. Use this example to describe the process in the above figure:

The user opens the Google browser and enters Qzone's URL, but he is not currently logged in, so he needs to enter the account password. Now enter the account password, and then click to log in.

The login request will first enter the Django routing system (there is actually middleware in front of the routing), indicating which resource you want to access, and then the request will be passed to the corresponding routing function.

At this time, the function receives the account password passed by the user and goes to the database (model, the signal can do some operations before and after the database) to make a match.

The current user name and password are correct, and then the view renders the page

Return the page to the browser, and the user enters his own Qzone

Install Python

Django itself is written in pure Python, so the first step in installing the framework is to make sure you have installed python2.x or python3.x, and you can download and install python from https://www.python.org/downloads/.

I have already installed Python3.x here.

$python3-VPython 3.5.2 installation

At present, my operating system is Mac and has been configured and installed with pip3 and python3. We can install it directly using pip:

# install the latest stable version of pip3 install django by default

Specify to install the django version, although this knowledge is not in django, but still want to say

# specify installation of version 1.9 pip install django==1.9

At present, the latest stable version is 1.10.You can enter the Python interpreter to import the django module to verify whether it is installed correctly

> import django

If you do not report an error during import, it means that the installation is successful, otherwise you may need to reinstall.

# Import django > import django# to view the current version > django.get_version () '1.10.5' to create a Django project

Django provides us with a django-admin instruction to make it easy for us to create a django project under the command line. You can use django-admin-help to see the help of this instruction, of course, if you want to do so.

Now let's take a look at one of the more commonly used parameters, which are all obtained through django-admin-- help.

Parameter description startproject create a complete project startapp create an apprunserver run the http service provided by django shell enter the shellmakemigrations generation database command of the environment to be django migrate execute the generated database command

Then let's use startproject to create a project

$django-admin startproject ansheng$ cd ansheng/$ lsansheng manage.py

The manage.py file is a command-line tool that allows you to interact with the Django project in a variety of ways. Typing python manage.py help shows that he provides us with those assignments, such as the following commands are commonly used:

Specify a description of createsuperuser to create a django background super administrator changepassword to change the password of the super administrator

It seems that these two are also the most commonly used. There is another parameter that is the same as the above django-admin-help. Please compare and test it yourself.

Ansheng/settings.py the global configuration file for the project, which is very important.

The routing configuration file for the ansheng/urls.py project, which is the main entry file for the django project.

There are some other unimportant documents that will not be elaborated.

Get the Django project up and running

Django has a built-in lightweight web development server that you can use during development, eliminating the need to install and configure nginx or apache.

If you have not started the server, please change to your project directory and run the following command:

Python manage.py runserverPerforming system checks...System check identified no issues (0 silenced). You have 13 unapplied migration (s). Your project may not work properly until you apply the migrations for app (s): admin, auth, contenttypes, sessions.Run 'python manage.py migrate' to apply them.August 08, 2016-11:29:42Django version 1.10, using settings' mysite.settings'Starting development server at http://127.0.0.1:8000/Quit the server with CTRL-BREAK.

This will start a local server on port 8000 and can only be connected and accessed from your computer. Now that the server is running, use a web browser to access http://127.0.0.1:8000/. You should see a delightful light blue Django welcome page.

Change the host address or port of this Development Server

By default, the runserver command starts the development server on port 8000 and only listens for local connections. To change the server port, pass in the port as a command line argument:

Python manage.py runserver 8080

By specifying an IP address, you can tell the server-allow non-local connection access. This feature is especially useful if you want to share the same development site with other developers. The IP address of 0.0.0.0 tells the server to listen on any network interface.

Python manage.py runserver 0.0.0.0:8000

After completing these settings, other computers on your local network will be able to access your IP address in a browser. For example: http://192.168.1.103:8000/

Example

In this example, we will cover many aspects of django, such as routing, views, models, templates, background management, and so on, which will be learned in the following chapters.

So what is this example? In fact, it is a very simple example, how to add users in the background and show users in the foreground? it's very simple, so let's do it next.

Based on the project ansheng created above, we are creating an app called users:

$python manage.py startapp users

For the first time, we also need to register app in our project. You can find the INSTALLED_APPS dictionary in ansheng/settings.py and add the APP name you just created:

INSTALLED_APPS = [. 'users',]

Because we need to use html, we also need to configure the template path file, first create a path to store the template file

$mkdir templates

Continue editing settings.py, find TEMPLATES, and modify DIRS as follows:

'DIRS': [os.path.join (BASE_DIR,' templates')]

Add a routing configuration to ansheng/urls.py:

From django.conf.urls import urlfrom django.contrib import admin# imports the view function usersfrom users.views import usersurlpatterns under app usersfrom users.views import usersurlpatterns = [url (r'^ admin/', admin.site.urls), # specifies the function url (r'^ users/$', users) corresponding to the route,]

The users/views.py view function is as follows:

From django.shortcuts import render# imports the UserInfo table in the model from .models import UserInfo# Create your views here.def users (request): # get all the users all_user = UserInfo.objects.all () # send the user information together with the front-end file to the browser return render (request, 'users.html', {' all_user': all_user})

The template/users.html content is as follows

Document {for user in all_user%} {{user.name}} {% endfor%}

Users/models.py profile

From django.db import models__all__ = ['UserInfo'] # Create your models here.class UserInfo (models.Model): name= models.CharField (max_length=30, verbose_name=' username') email = models.EmailField (verbose_name=' user mailbox')

Users/admin.py profile

From django.contrib import adminfrom .models import * # Register your models here.# registers UserInfo with admin admin.site.register (UserInfo)

Finally, we generate the database:

$python manage.py makemigrations$ python manage.py migrate

Create a Super Admin user

$python manage.py createsuperuser# username Username (leave blank to use 'ansheng'): ansheng# Yo box address, can be empty Email address: # password Password: # confirm password Password (again): Superuser created successfully.

Open http://127.0.0.1:8000/admin/ to log in to the background and enter the user and password we just created

Find the app we just added, and then click ADD to add one or more users:

Continue to open http://127.0.0.1:8000/users/ and you can see the user you just added. You can try to add another user and refresh the page to see if the new user you just added will be displayed.

# Python full Stack Road # Django

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