Learn python from scratch with me (8) full stack development

foreword

Looking back, I talked about python syntax programming, compulsory introductory basics and network programming, multi-thread/multi-process/coroutine, etc., and then talked about database programming articles MySQL, Redis, MongoDB articles, and machine learning. Turning forward, the series of articles have been sorted out:

1. Learn python from scratch with me (1) Compulsory programming grammar
2. Learn python from scratch with me (2) Network programming
3. Learn python from scratch with me (3) Multi-thread/multi-process/ Coroutine
4. Learn python from scratch with me (4) Database programming: MySQL database
5. Learn python from scratch with me (5) Database programming: Redis database
6. Learn python from scratch with me (6) ) Database programming: MongoDB database
7. Learn python from scratch with me (7) Machine learning

This series of articles is based on the following learning routes. Due to the large content:

Learn python from scratch to advanced advanced roadmap

Pay attention to the official account: python technology training camp , learn advanced step by step

Python resources suitable for zero-based learning and advanced people:

① Tencent certified python complete project practical tutorial notes PDF
② More than a dozen major manufacturers python interview topic PDF
③ Python full set of video tutorials (zero foundation-advanced advanced JS reverse)
④ Hundreds of project actual combat + source code + notes
⑤ Programming grammar - machine learning -Full-stack development-data analysis-crawler-APP reverse engineering and other full set of projects + documents
⑥ Exchange and study
⑦ Want to take part-time orders

1. Web page development

1. HTML5

HTML5 is the fifth version of Hyper Text Markup Language, a standard for creating web pages and web applications. Compared with the previous HTML version, HTML5 adds some new functions and APIs, which is to adapt to the needs of the modern Internet, especially the needs of mobile devices and embedded devices.

Key features of HTML5 include:

1. Semantic tags : HTML5 introduces some new tags, such as header, nav, section, article, etc. These tags make web content more semantically meaningful and improve readability and accessibility.

2. Multimedia support : HTML5 allows audio and video to be directly embedded in web pages without plug-ins, which greatly simplifies the development of web applications. In addition, HTML5 supports adaptive resizing of videos to fit different devices.

3. Canvas drawing function : HTML5 introduces a new API called Canvas, which can draw graphics, charts, animations, etc. on web pages. The Canvas API provides more interactivity and visualization for web applications.

4. Local storage : HTML5 introduces two local storage APIs: localStorage and sessionStorage. These APIs allow web applications to store data locally, improving application performance and reliability.

5. Web Worker : HTML5 introduces a new API called Web Workers, which allows JavaScript to run in the background without blocking the user interface. This can improve the performance and responsiveness of web applications.

6. Enhanced form functions : HTML5 introduces some new form elements and attributes, such as date, time, email, url, number, range, etc. These elements can greatly improve the user interaction experience of the website and reduce the dependence on JavaScript .

7. WebSocket : HTML5 introduces a new network protocol called WebSocket, which can open persistent connections in modern web browsers and transmit data in real time. This enables web applications to quickly and reliably implement two-way communication between the server and the client.

8.GeoLocation : HTML5 introduces a new API called GeoLocation, which allows web applications to obtain the user's geographic location. This opens up endless possibilities for many types of web applications, such as mapping and location applications.

In summary, HTML5 is an important web technology standard, which provides many new functions and APIs, which can greatly expand the functionality and performance of modern web applications. If you're going to learn web development, then HTML5 is an important technology worth learning.

2. CSS

CSS, or Cascading Style Sheets, is a language used to describe the appearance and layout of web pages. In web development, CSS is often used in conjunction with HTML to control the style of web pages.

Here are some detailed explanations of CSS:

1. CSS Syntax

CSS uses selectors and properties to describe the style of a web page. Selectors are used to select the HTML elements whose styles are to be changed, while attributes are used to describe the styles to be changed. The syntax of CSS is as follows:

选择器 {
属性1: 值1;
属性2: 值2;
…
}

Selectors typically use an HTML element's tag name, class name, or ID to specify the element whose style is to be changed. For example, the following is a CSS rule that sets the font color of all h1 elements to red:

h1 {
color: red;
}

2. CSS rules

A CSS rule consists of a selector and a set of property declarations. Each attribute declaration consists of an attribute name and an attribute value. For example, the following is a CSS rule that sets the font color to white and the background color to blue for all buttons with class "button":

.button {
color: white;
background-color: blue;
}

3. CSS Units

CSS supports various units to represent size, distance and time. Here are some common CSS units:

• px : pixels
• em : the font size relative to the parent element
• rem : font size relative to the root element
• % : relative to the size of the parent element
• vh/vw : percentage of viewport height/width

4. CSS Box Model

The CSS box model is used to describe the size and positioning of HTML elements. Each HTML element is a "box" that consists of four parts: the content area, the padding area, the border area, and the margin area. The following is a diagram of the CSS box model:

+-----------------------+
|         外边距        |
|      +-------------+  |
|      |   边框      |  |
|      |  +---------+|  |
|      |  |内边距   ||  |
|      |  |         ||  |
|      |  |         ||  |
|      |  |         ||  |
|      |  +---------+|  |
|      +-------------+  |
|         内容          |
+-----------------------+

5. CSS layout

CSS can be used to control the layout of web pages, including how to position and arrange HTML elements. Here are some common CSS layout techniques:

• position attribute : The element can be positioned relative to its parent element, the top of the document, or the bottom of the document.
• float attribute : You can make elements float around the text, creating multi-column layouts.
• display property : You can change the way the element is displayed, such as converting the element to a table or flexbox layout.
• flexbox layout : Provides a flexible way to arrange and align HTML elements, especially useful for creating responsive layouts.

3. JavaScript

JavaScript is a scripting language used to write interactive web pages. Using JavaScript, developers can interactively modify HTML and CSS, respond to user input, process data, etc. by utilizing APIs provided by web browsers.

Here are some JavaScript details:

1. JavaScript syntax

The basic syntax of JavaScript is similar to other programming languages, including variables, operators, loops, conditional statements, functions, etc. JavaScript code can be embedded in a web page or called from an external file. Here is an example of simple JavaScript code that adds two numbers and prints the result to a web page:

<script> var a = 1; var b = 2; var c = a + b; document.write(c); </script>

2. JavaScript variables

JavaScript variables are used to store data, which can be of data types such as numbers, strings, Boolean values, arrays, and objects. Variables must be declared before they are used. Variables can be declared using the keywords var, let, or const, depending on the scope and mutability of the variable. Here is an example of declaring a variable using var:

var name = “John”;
var age = 30;
var isStudent = true;

3. JavaScript Arithmetic Operators

JavaScript supports various arithmetic operators, including addition, subtraction, multiplication, division, modulo (remainder), etc. Here is an example using arithmetic operators:

var a = 10;
var b = 5;
var c = a + b; // 15
var d = a - b; // 5
var e = a * b; // 50
var f = a / b; // 2
var g = a % b; // 0

4. JavaScript functions

A JavaScript function is a reusable block of code that takes input (parameters), performs some action, and returns some result. JavaScript functions can be defined using the function keyword. Here is an example of a simple JavaScript function that takes two numbers as arguments and returns their sum:

function add(a, b) {
return a + b;
}

5. JavaScript events

JavaScript events refer to interactive behaviors or states that occur within the browser, such as clicking buttons, scrolling pages, and so on. By writing event handlers in JavaScript code, specific actions can be performed when an event occurs. Here's an example of a simple JavaScript event handler that displays a message when the user clicks a button:

Click me!

6. JavaScript objects

A JavaScript object is a collection of related properties and methods. Properties are characteristics of an object, and methods are behaviors of an object. JavaScript objects can be defined through object literals, constructors, or classes. Here's an example of defining a JavaScript object using an object literal:

var person = {
firstName: “John”,
lastName: “Doe”,
age: 30,
fullName: function() {
return this.firstName + " " + this.lastName;
}
};

7. JavaScript asynchronous programming

JavaScript asynchronous programming is a special programming model that allows JavaScript code to wait for certain operations to complete without being blocked. Common asynchronous programming patterns include callback functions, promises, and async/await. The following is an example of asynchronous programming using a callback function, which uses the XMLHttpRequest object to fetch data from the server and calls the callback function when the data is ready:

var xhttp = new XMLHttpRequest();
xhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
// 数据就绪，执行成功回调
var data = JSON.parse(this.responseText);
handleData(data);
}
};
xhttp.open(“GET”, “https://example.com/api/data”, true);
xhttp.send();

4. jQuery

jQuery is a popular JavaScript library that simplifies JavaScript programming by providing a convenient API for manipulating HTML documents and handling events.

Here are some jQuery details:

1. jQuery syntax

jQuery manipulates HTML elements through selectors, providing a convenient and quick syntax for manipulating the Document Object Model (DOM).

The $() function can receive a selector string or an HTML document object, and returns a jQuery object, which provides many jQuery functions. Here's a basic jQuery example:

$(document).ready(function(){
// 在文档准备好后，执行这里面的代码
});

2. jQuery selector

jQuery selectors support the same syntax as CSS selectors, and elements can be selected using tag names, classes, and IDs. Here are some examples of commonly used jQuery selectors:

// 选择所有元素
$(document).find(‘*’)

// 选择ID为my-element的元素
$(‘#my-element’)

// 选择class为my-class的元素
$(‘.my-class’)

// 选择所有button元素
$(‘button’)

3. jQuery manipulates HTML elements

Through the jQuery object, you can easily operate on HTML elements. Here are some examples of commonly used jQuery manipulation HTML elements:

// 获取元素的文本内容
var text = $(‘p’).text();

// 设置元素的文本内容
$(‘p’).text(‘new text’);

// 获取元素的属性值
var href = $(‘a’).attr(‘href’);

// 设置元素的属性值
$(‘a’).attr(‘href’, ‘new href’);

// 显示元素
$(‘div’).show();

// 隐藏元素
$(‘div’).hide();

4. jQuery handles events

jQuery can help simplify the process of handling events such as mouse clicks, mouse movements, keyboard key presses, and more. Here are some examples of commonly used jQuery handling events:

// 在元素上绑定单击事件
$(‘button’).click(function(){
// 执行单击事件的代码
});

// 在文档上绑定键盘按键事件
$(document).keypress(function(event){
// 执行键盘按键事件的代码
});

// 在元素上绑定鼠标移动事件
$(‘p’).mousemove(function(event){
// 执行鼠标移动事件的代码
});

5. jQuery effect

jQuery provides a series of effect functions that can manipulate HTML elements through animations and gradients. Here are some examples of commonly used jQuery effects:

// 使用渐隐效果隐藏元素
$(‘p’).fadeOut();

// 使用渐显效果显示元素
$(‘p’).fadeIn();

// 使用动画函数移动元素
$(‘div’).animate({
left: ‘250px’,
top: ‘250px’
});

// 在元素上绑定滚动事件
$(window).scroll(function(){
// 执行滚动事件的代码
});

Five, Vue detailed explanation

Vue is a popular JavaScript framework for building interactive, single-page web applications. Its main features are lightweight, efficient and easy to learn. Vue provides many features such as reactive data binding, component system, routing and state management, etc.

The following are some detailed explanations of Vue:

1. Vue components

Vue components are a core concept of Vue applications that allow you to split the user interface into independent, reusable parts. Each Vue component has its own template, script and style.

Here is an example of a simple Vue component:

<template>
  <div>
    <h1>{
   
   { title }}</h1>
    <p>{
   
   { description }}</p>
  </div>
</template>

<script>
export default {
  name: 'MyComponent',
  props: {
    title: String,
    description: String
  }
}
</script>

<style>
h1 { font-size: 24px }
p { font-size: 16px }
</style>

2. Vue responsive data binding

Vue uses its reactivity system to automatically track changes in application state and reflect those changes in views. When application state changes, all Vue components that use these states will re-render with the latest values.

Here is a simple Vue reactive data binding example:

<template>
  <div>
    <p>Counter: {
   
   { counter }}</p>
    <button @click="increment">Increment</button>
  </div>
</template>

<script>
export default {
  data() {
    return {
      counter: 0
    }
  },
  methods: {
    increment() {
      this.counter++
    }
  }
}
</script>

3. Vue routing

Vue Router is an official Vue.js routing plugin for implementing routing functions in Vue applications, such as switching between different pages, backward and forward history, etc.

Here is a simple Vue routing example:

import Vue from 'vue'
import VueRouter from 'vue-router'
import Home from './views/Home.vue'
import About from './views/About.vue'

Vue.use(VueRouter)

const routes = [
  { path: '/', component: Home },
  { path: '/about', component: About }
]

const router = new VueRouter({
  mode: 'history',
  routes
})

export default router

4. Vue state management

Vuex is a state management library used in Vue applications to manage the state of the application. It provides a unified approach to data management, ensuring predictability and maintainability of application state.

Here is a simple Vuex example:

import Vue from 'vue'
import Vuex from 'vuex'

Vue.use(Vuex)

const store = new Vuex.Store({
  state: {
    count: 0
  },
  mutations: {
    increment(state) {
      state.count++
    }
  },
  actions: {
    incrementAsync({ commit }) {
      setTimeout(() => {
        commit('increment')
      }, 1000)
    }
  },
  getters: {
    doubleCount(state) {
      return state.count * 2
    }
  }
})

export default store

5. Vue tools

Vue provides a series of tools and plugins to help developers improve efficiency and development experience during the development process. Among them, Vue Devtools is a very popular Chrome extension, which provides a developer-friendly interface to help developers debug Vue applications more easily. In addition, Vue also provides some libraries and plug-ins, such as Vue Router, Vuex, Vue CLI and Vue Test Utils, etc., to help developers better build and test Vue applications.

2. Django

One-step Python Django deployment, talk about Python Django framework

Django is a web application framework developed in Python. It follows the MVC (Model-View-Controller) design pattern and aims to help developers build and maintain high-quality web applications faster and easier. Django provides a powerful infrastructure and tools to handle complex business logic, ORM mapping, security and other issues.

Here are some common elements of Django development:

• URL configuration : Django provides a URL routing system that allows developers to map requests to corresponding view functions.

• View function : Django's view function processor is responsible for obtaining the corresponding data from the request, and obtaining or updating data from the database according to logic processing, and finally returns the result to the front-end page.

• Models : Models in Django are Python classes that interact with the database. Developers can use the ORM (Object Relational Mapping) mechanism to map Python classes with corresponding database tables, making data manipulation more convenient while maintaining code readability and maintainability.

• Templates : Django's template system helps developers create dynamic web UI pages. Developers can render dynamic data to HTML pages by using the Django Template Language.

• Form : Django provides form processing and validation functions, enabling users to easily submit data and ensure the correctness of the data.

• Background management : Django provides a built-in background management system that helps developers easily manage the background of web applications, including adding, updating, and deleting data, authorizing access, and more.

In conclusion, Django provides developers with good web application development infrastructure, tools, and specifications so that they can build high-quality web applications faster and easier.

1. Django Elementary

1. What is Django?

Django is a web framework that follows the MVC (Model-View-Controller) architecture, designed to help developers build and maintain high-quality web applications faster and easier. It is written in Python and has simple syntax and rich functionality.

2. Install Django

Before using Django, you need to install it. You can install Django with the following command:

pip install django

3. Create a Django project

To create a new Django project, execute the following command:

django-admin startproject myproject

"myproject" is your project name. This command will create a new directory containing the following files:

myproject/
    manage.py
    myproject/
        __init__.py
        settings.py
        urls.py
        asgi.py
        wsgi.py

4. Run the Django application

To run a Django application, use the following command:

python manage.py runserver

This command will start the development web server which will run on port 8000 of localhost by default.

5. Create a Django application

To create a new Django application, execute the following command:

python manage.py startapp myapp

"myapp" is your application name. This command will create a new directory containing the following files:

myapp/
   __init__.py
   admin.py
   apps.py
   models.py
   tests.py
   views.py

6. Django view

Django views are Python functions that process HTTP requests and return HTTP responses. To create a Django view, first define a Python function, then wrap it as a view with a decorator:

from django.http import HttpResponse
    
def my_view(request):
    return HttpResponse("Hello, world")

The view above will respond with "Hello, world" text when an HTTP request is received.

7. Django Templates

Django templates are HTML files that allow you to dynamically add data to HTML. To use Django templates, define an HTML file and use the Django templating language to insert data into the file:

{% extends "base.html" %}
    
{% block content %}
    <h1>{
   
   { page_title }}</h1>
    <p>{
   
   { page_content }}</p>
{% endblock %}

The above code will define an HTML block named "content" in the HTML template with extension "base.html" and insert dynamic data inside it referenced by the variables "page_title" and "page_content".

8. Django Models

Django models are Python classes that interact with the database. To create a Django model, define a Python class in which you define attributes and relationships using Django ORM (Object Relational Mapping):

from django.db import models
    
class Person(models.Model):
    first_name = models.CharField(max_length=30)
    last_name = models.CharField(max_length=30)

The code above defines a Django model named Person with two CharField properties: first_name and last_name.

9. Django Admin Site

The Django admin site is a built-in web interface for easily managing the backend of a Django application. You can make Django models manageable by registering them in the Django admin site:

from django.contrib import admin
    
from .models import Person
    
admin.site.register(Person)

The above code will register a Django model called "Person" in the Django admin site.

2. Advanced Django

1. Django view classification

Django supports different types of views, and the following types of views can be created as needed:

• Function Views : Basic Django views implemented as Python functions.
• Class-based views : Python class-based Django views that provide a lot of extra functionality.
• Generic Views : Pre-built Django views including functionality for common use cases.
• Viewsets : Django views for the API, supporting CRUD (create, read, update, delete) operations.

2. Django template inheritance

Django template inheritance refers to defining a common template in one HTML file and extending that template in other HTML files. To use Django template inheritance, create a base HTML template that contains common blocks, and use the {% extends %} tag to specify which templates to extend:

<!-- base.html -->
    
<html>
<head>
    {% block head %}
       <title>{% block title %}My Site{% endblock %}</title>
    {% endblock %}
</head>
<body>
    {% block content %}
    {% endblock %}
</body>
</html>

<!-- child.html -->
    
{% extends "base.html" %}
    
{% block title %}My amazing website{% endblock %}
    
{% block content %}
   <p>Welcome to my amazing website!{% endblock %}

The code above will create a base template and an extended template and insert custom blocks to render dynamic data.

3. Django form

Django's forms system provides you with tools to create HTML forms and manipulate form data. To define a Django form, create a Python class that inherits from Django's Form class:

from django import forms
    
class ContactForm(forms.Form):
    name = forms.CharField(max_length=100)
    email = forms.EmailField()
    message = forms.CharField(widget=forms.Textarea)

The code above defines a Django form called ContactForm that has three form fields: name, email, and message.

4. Django middleware

Django middleware is a reusable software component used to add extra functionality between HTTP requests and responses. To create a Django middleware, create a Python class with one of the following methods: process_request , process_view , process_exception or process_response .

class MyMiddleware:
    def __init__(self, get_response):
        self.get_response = get_response
    
    def __call__(self, request):
        # 每个请求都会执行这里
        response = self.get_response(request)
        # 每个响应都会执行这里
        return response

The above code defines a MyMiddleware class, in which the __init__ method initializes the middleware, and the __call__ method implements the logic processing of the middleware.

5. Django Signals

Django signals are an observer pattern for defining events and actions performed based on events in Django applications. To use Django signals, define a Python function and associate that function with a signal using the @receiver decorator:

from django.dispatch import receiver
from django.db.models.signals import post_save
from django.contrib.auth.models import User
    
@receiver(post_save, sender=User)
def create_user_profile(sender, instance, created, **kwargs):
    if created:
       UserProfile.objects.create(user=instance)

The code above defines a Python function called create_user_profile and associates it with the User model when the post_save signal occurs.

Three, Django advanced

1. Django performance optimization

Django performance optimization refers to improving the performance of Django applications through some techniques and tools. Here are some best practices for optimizing Django performance:

• Enable caching : Using caching can drastically reduce the response time of your Django application.
• Use a CDN : Using a content delivery network (CDN) can speed up the loading of static resources in your Django application.
• Turn on Gzip compression : Enabling Gzip compression can reduce the size of HTML, CSS, and JavaScript files, thereby improving page loading speed.
• Use asynchronous tasks : Use asynchronous task queues to distribute long-running or computationally intensive tasks to background computing resources, thereby improving the responsiveness of Django applications.
• Improve database queries : You can improve the performance of your Django applications by using indexes and sensible queries to optimize database performance.
• Storing static files on a third-party service : By sharing static files you can reduce the load on your Django application and thus improve responsiveness.

2. Django Security

Django security refers to taking steps to protect a Django application's data and users from potential threats. Here are some best practices for securing Django applications:

• Use HTTPS : Use HTTPS to encrypt all transmitted data of the Django application to improve data security.
• Protection against Cross-Site Request Forgery (CSRF) attacks : Django provides built-in CSRF protection to prevent malicious users from submitting malicious requests from other websites.
• Prevent SQL injection attacks : Using ORM can prevent SQL injection attacks.
• Protection against cross-site scripting (XSS) attacks : Filtering and escaping input to Django applications prevents XSS attacks.
• Turn off debug mode : Turning off debug mode for Django applications in production reduces the risk of malicious users

3. Performance tuning

1. Storage layer tuning

The storage layer is an important part of a web application and it is responsible for storing and retrieving data. In this post, we will focus on tuning the storage layer to improve the performance and scalability of web applications.

1. Database design

Good database design can greatly improve the performance and scalability of your application. When designing a database, the following principles should be followed:

• Correct data type : Choosing the correct data type is very important both for storing data and retrieving it. Unnecessary data types should be avoided, such as storing integers as strings, etc.
• Use of indexes : Indexes can help speed up database queries, but too many indexes can slow down database writes. Therefore, indexes should be used only when necessary.
• Database paradigm : Database paradigm helps in reducing data redundancy and improving data consistency. However, a normalized database may require more JOIN operations, thereby reducing query performance. Therefore, a balance should be found when designing a database.

2. Database query optimization

Database queries are a key factor affecting web application performance. Here are some techniques for optimizing database queries:

• Retrieve only necessary columns : Avoid retrieving unnecessary columns, which can reduce the burden on the database and improve database query performance.
• Use indexes : Indexes can help speed up queries, but too many indexes can slow down writes. Therefore, a balance needs to be found when designing indexes.
  Use batch queries: Batch queries allow multiple queries to be sent at the same time, thereby reducing the number of database interactions and improving query performance.
• Avoid full table scans : By using the WHERE clause or limiting the size of the query result set, you can avoid scanning the entire table, thereby improving query performance.

3. Cache

Caching is a technique for compressing data and improving query performance. Here are some techniques for using caching to optimize database access:

• Use a local cache : A local cache can cache frequently used data and reduce database access.
• Use Distributed Cache : Distributed cache can cache data located on different servers, thus improving query performance.
• Use a cache invalidation strategy : A cache invalidation strategy can ensure that the data in the cache is kept in sync with the data in the database, thereby avoiding the use of outdated data.

4. Database replication

Replicating the database to multiple nodes can improve the read performance and fault tolerance of the application. Here are some techniques for optimizing applications using database replication:

• Master-slave replication : Write data on the master server and read data on multiple slave servers. This can effectively reduce the burden on the master server and improve read performance.
• Master-Master Replication : Data is written and read on multiple master servers, which increases application fault tolerance and reduces single points of failure.
• Partition replication : Partitioning data to different servers can improve query speed and reduce the load on a single server.

To sum up, storage layer tuning is a very important task that has a great impact on the performance and scalability of web applications. By optimizing aspects such as database design, query, caching and replication, the performance of web applications can be effectively improved.

Two, celery asynchronous task

In web applications, it is sometimes necessary to perform long-running tasks, such as sending emails, generating PDF files, and so on. If these tasks are performed synchronously, it will greatly reduce the performance and responsiveness of the web application. At this time, asynchronous tasks become a good solution. Celery is a popular Python asynchronous task framework that helps us perform asynchronous tasks easily.

Here are some optimization tips for Celery asynchronous tasks:

1. Use asynchronous tasks

If a long-running task does not need to return results immediately, it is best to implement it as an asynchronous task. Asynchronous tasks do not block the application's main thread and allow the application to continue processing other requests. For long calculations or I/O operations that need to be performed, it is best to use Celery to implement asynchronous tasks.

2. Set the task timeout

If you do not specify a task timeout, the task will continue to execute when it takes up too many resources or cannot be completed on time. This leads to high CPU and memory utilization which can eventually cause the application to crash. Therefore, it is necessary to set the task timeout. In Celery, we can use the time_limit and soft_time_limit parameters to set the task timeout.

3. Parallelization of intensive tasks

If there are many intensive tasks to perform, it is best to parallelize them. Celery provides a convenient way to parallelize tasks - using concurrent tasks. By adjusting Celery's worker and concurrency configurations, we can easily execute large numbers of tasks in parallel.

4. Task result cache

If you need to call the same asynchronous task multiple times and the task result does not change frequently, it is better to cache the task result in memory or persistent storage. This way, applications can get task results faster and avoid performing the same task repeatedly. Celery provides a convenient way to cache task results - using a cache backend.

5. Optimization of message queue

Celery uses message queues to handle asynchronous tasks. For high-traffic applications, the performance of message queues is very important. Here are some tips for optimizing message queues:

• Selection of message queue : It is very important to choose a message queue with good performance and reliability, such as RabbitMQ, ActiveMQ, Redis, Kafka, etc.
• Configuration of the message queue : Setting the prefetch count and batch size of the message queue can have a significant impact on the efficiency of consumers.
• Monitoring of message queues : Regularly monitor message queues to ensure their performance and availability.

To sum up, using Celery for asynchronous task execution is an important means to improve the performance of web applications. By setting task timeouts, parallelizing intensive tasks, caching task results, and optimizing message queues, the execution efficiency and reliability of asynchronous tasks can be better improved.

3. Django caching mechanism

When developing web applications, caching is one of the important means to improve performance. Django provides a variety of caching mechanisms, including memory caching, file system caching, database caching, and caching framework extensions. This article will introduce the use and optimization of Django's caching mechanism in detail.

1. Open the cache

In Django's settings.py file, the following cache settings are defined:

CACHES = {
    'default': {
        'BACKEND': 'django.core.cache.backends.memcached.MemcachedCache',
        'LOCATION': '127.0.0.1:11211',
    }
}

This configuration defines a cache configuration named "default" that uses the MemcachedCache cache backend, which is one of Django's default cache backends. Other cache backends include local memory cache (LocMemCache), file system cache (FileBasedCache), and database cache (DatabaseCache). In addition, you can also use third-party cache backends, such as RedisCache, HDFSCache, etc.

After caching is enabled, we can use Django's built-in caching API for caching read and write operations. Here is a simple example:

from django.core.cache import cache

# 缓存一个数据，有效期为100秒
cache.set('my_key', 'my_value', timeout=100)

# 从缓存中获取一个数据
my_data = cache.get('my_key')
if my_data is not None:
    # 命中缓存，使用缓存中的数据
    pass
else:
    # 没有命中缓存，执行其他操作
    pass

2. Cache key design

The design of the cache key is very important because it determines how the cache is stored and accessed. We can generate cache keys in a number of ways, including:

• Using URL and Parameters :
  Concatenate URL and query parameters into a string as a cache key. This method is suitable for some common query pages, such as search result pages. Using this method requires attention to the order in which query parameters are processed to avoid generating different cache keys due to different order of parameters.

• Use primary key of database object :
  Use the primary key of the database object as the cache key. This method is suitable for caching for specific objects, such as article detail pages.

• Custom Rules :
  Use custom rules to generate cache keys. For example, use timestamp and other information to mark the version number of the cache, and change the version number when the content changes.

When designing cache keys, cache expiration time and cache hit ratio also need to be considered. For different pages and requirements, we need to choose different caching strategies and expiration times.

3. Use a caching framework

The Django cache framework is a very scalable caching tool that comes with Django, which can implement many advanced functions and custom extensions. It can run on a variety of cache backends and supports various cache policies, such as cache expiration time, cache version, cache dependencies, etc. The caching framework can help us easily implement efficient caching and avoid cumbersome processing of some low-level details.

It should be noted that the caching framework is not suitable for all situations. For some specific requirements, we may need to customize the caching mechanism to achieve better performance and effects.

4. Cache cleaning mechanism

For some content that needs to be updated, we need to clear the relevant data from the cache in time. For example, when we modify the content of an article, we need to clear the cache in time. Django provides a variety of cache cleaning strategies, including:

• Manual Clearing:
  Clearing the cache manually is the most common method. We can call methods in code cache.delete()to clear the specified cache or all caches.

• Automatic cleaning:
  When using the automatic caching mechanism, we can define some cleaning rules and conditions, such as based on time, based on cache size, based on cache version, etc. When certain conditions are met, the cache framework will automatically clean up the cache.

5. Cache optimization

The performance of the Django caching framework directly affects the performance of web applications. Here are some suggestions for cache optimization:

• Use an efficient caching backend . For example, using Memcached as a cache backend can improve cache access speed and concurrency performance.

• Avoid generating duplicate cached data . When multiple codes generate the same cache data at the same time, it will cause unnecessary cache update and invalidation operations, reducing the cache hit rate.

• Use cache partitions . Store different types of data in different cache partitions to avoid mixing irrelevant data and reduce the cache hit rate.

• Use cache auto-increment and auto-decrement . Cache auto-increment and auto-decrement are an efficient cache update method that can avoid frequent cache query and write operations.

• Set the cache invalidation time reasonably . Different types of data need to set different cache expiration times according to their own characteristics and needs, so as to avoid excessive storage and invalid consumption of cached data.

To sum up, Django's caching mechanism is one of the important means to improve the performance of web applications. We need to select an appropriate cache strategy and cache configuration according to the actual situation, optimize the design of the cache key and the cache cleaning mechanism, and pay attention to the performance and scalability of the cache.

Four, Nginx service

Nginx is a lightweight, high-performance web server and reverse proxy server, often used to build high-availability and high-performance web applications. In full-stack development, Nginx optimization is very important because it can directly affect the performance and reliability of web applications. This article will introduce the optimization and performance tuning methods of Nginx in detail.

1. Reasonably configure Nginx

When using Nginx, we need to configure Nginx reasonably, including adjusting parameters such as the number of worker processes, the number of connections, and cache. Here are some suggestions:

• Adjust the number of worker processes:
  The number of worker processes directly affects the performance of Nginx, so it is necessary to set an appropriate number of worker processes according to the server's hardware resources and actual load conditions. You can use the nginx -t command to check the configuration file for errors and the nginx -s reload command to reload the configuration.

• Adjust the number of connections:
  The setting of the number of connections is also very important, which will lead to performance bottlenecks during high concurrent access. Nginx provides keepalive_timeout to specify the maximum time for idle connections, during which time the connection is kept. The keepalive_timeout and the maximum number of connections need to be set reasonably according to the actual situation.

• Use cache:
  Nginx also provides a cache mechanism, you can use the proxy_cache_path directive of the ngx_http_proxy_module module to set the cache path and cache size. Using cache can effectively reduce server pressure and improve response speed.

2. Use advanced features of Nginx

Nginx provides many advanced features and extensions, such as load balancing, HTTPS, reverse proxy, dynamic modules, page compression, etc. These features can help us achieve highly available, high-performance web applications. Here are some suggestions:

• Use load balancing:
  Load balancing is a technique of distributing load to multiple servers that can improve the availability and performance of web applications. Nginx provides four load balancing algorithms: round robin, IP Hash, fair and random, you can choose the appropriate load balancing algorithm according to the specific situation.

• Use HTTPS:
  HTTPS is a secure web connection protocol that guarantees data security and privacy. Nginx provides SSL support, you can use the ngx_http_ssl_module module to set HTTPS certificates to implement HTTPS protocol access.

• Use a reverse proxy:
  A reverse proxy is a proxy method that forwards requests to multiple servers and returns responses to clients. Nginx can be used as a reverse proxy server to implement functions such as load balancing, caching and security.

• Use dynamic modules:
  A dynamic module is a module added to Nginx in the form of a plug-in, which can add some advanced functions and support new protocols. For example, Nginx provides the ngx_http_lua_module module, which can extend Nginx with Lua scripts.

• Page compression:
  Nginx supports enabling the gzip function, which can compress static resources such as HTML, CSS, and JS, and reduce page response time and network bandwidth consumption.

3. Monitor and optimize Nginx

It is also very important for the monitoring and optimization of Nginx, which can find and solve problems in real time and improve the performance and reliability of web applications. Here are some suggestions:

• Monitoring Nginx:
  You can use the ngx_http_stub_status_module module in Nginx to monitor the status and performance indicators of Nginx in real time, such as the number of connections, request processing time, error rate, etc.

• Nginx log:
  Nginx provides a variety of log formats and logging levels, which can record access information, error information and debugging information. Using Nginx logs can help us understand the status and performance indicators of web applications in real time.

• Nginx performance optimization:
  You can use some performance optimization techniques, such as HTTP caching, resource consolidation and compression, DNS preloading, etc., to improve the performance and quality of web applications.

To sum up, Nginx optimization and performance tuning are very important for full-stack development. We need to configure Nginx reasonably, use advanced functions and extensions of Nginx, monitor and optimize Nginx, in order to build high-availability, high-performance web applications.

Four, Django SDK development

Django is a popular Python web framework that provides a way to quickly develop web applications, including a series of development tools and libraries. In full-stack development, Django's SDK development is also very important, because it can directly affect the performance and reliability of web applications. This article will introduce how to use Django for SDK development and performance tuning.

1. Create a Django SDK project

First, we need to create a new project using Django, we can use the following command:

django-admin startproject myproject

This command will create a Django project named myproject, and Django will automatically create some necessary files. Next, we will create the SDK application in this project.

2. Create a Django SDK application

In a Django project, we can create a new application with the following command:

python manage.py startapp sdkapp

This command will create an application directory named sdkapp, and Django will automatically create some necessary files. Next, we need to create some view functions and APIs in the application to handle requests and return responses.

3. Create a Django SDK view function

In the Django SDK application, we need to create some view functions to implement the functions of the API. Here is an example view function:

from django.http import JsonResponse

def hello(request):
    return JsonResponse({'message': 'Hello, world!'})

The view function will receive a request object named request and return a response in JSON format with a message: "Hello, world!". We can use Django's routing system to map this view function to an API interface.

4. Create Django SDK route

In Django, we can use the urls.py file to define routes and map URL addresses to corresponding view functions. Here is an example route definition:

from django.urls import path
from sdkapp.views import hello

urlpatterns = [
    path('hello', hello, name='hello'),
]

In this example, we define an API interface called hello, which will use the hello view function we created earlier to handle requests. We can add this route to the main Django application, for example in the myproject/urls.py file.

5. Perform Django performance tuning

For Django SDK development, performance tuning is also very important, which can effectively improve the performance and reliability of web applications. Here are some common performance tuning techniques:

• Eliminate unnecessary middleware:
  Django provides a lot of middleware to perform various tasks, such as security policies, caching, and authentication. However, using too many middleware may affect performance, so we need to choose the appropriate middleware and remove unnecessary middleware.

• Caching:
  Django provides a variety of caching methods, which can cache view functions, templates, and data query results to improve response speed. For example, we can use Django's built-in cache decorator to cache response content.

• Database tuning:
  The ORM in Django has already handled most of the database operations for us, but when dealing with large amounts of data, we also need to consider some database tuning techniques, such as index optimization, query optimization, and table partitioning.

• Using asynchronous tasks:
  Django provides support for asynchronous tasks, which can be implemented using tools such as Celery and Redis. Asynchronous tasks can put some time-consuming operations in the background for execution, avoid blocking the main thread, and improve the performance and response speed of web applications.

• Use a web server:
  In a production environment, a web server is usually used to deploy Django applications, such as Apache, Nginx, and Gunicorn. These web servers provide some performance tuning options, such as enabling caching, compression, and load balancing.

To sum up, Django's SDK development and performance tuning are very important for full-stack development. We need to create Django projects and applications, define view functions and routes, and perform appropriate performance tuning to build highly available, high-performance web applications.

5. Docker container

Docker is a lightweight container technology that can package applications and dependencies into a portable container so that applications can run in any environment without having to worry about environment configuration issues. For full-stack development, Docker can help us easily deploy applications in development, testing, and production environments, while also improving application reliability and performance. This article will introduce how to use Docker containers for performance tuning of full-stack development.

1. Basic knowledge of Docker containers

When using Docker for full-stack development, you first need to understand the basics of Docker containers, including the following concepts:

• Image : A static template for a Docker container that includes all dependencies, configuration files, and applications needed to run the container. Images can be defined through a Dockerfile.

• Container : A running instance of a Docker image that can run applications and services in a container. Containers can be started, stopped, deleted and restarted at any time.

• Dockerfile : The definition file of the Docker image, which contains all the configuration information required for the container to run, such as the base image, dependency installation, environment variables, and startup commands.

2. Use Docker to deploy full-stack applications

Deploying a full-stack application with Docker typically requires the creation of multiple containers, each responsible for running a service or application. For example, we can create an Nginx container to handle web requests, a database container to handle data storage, a back-end application container to handle business logic, a front-end application container to provide the web interface, etc.

In Docker, we can use the docker-compose tool to define and manage the running status of multiple containers. docker-compose uses YAML files to describe the configuration and dependencies of multiple containers. For example, here is a sample docker-compose.yml file:

version: '3'
services:
  web:
    build: ./myapp
    ports:
      - "8000:8000"
  db:
    image: postgres

In the above example, we defined two Docker containers: web and db. The web container is built using the Dockerfile in the myapp directory, and port 8000 of the container is mapped to port 8000 of the host. The db container is built using the official PostgreSQL image.

3. Use Docker for performance tuning

Deploying applications with Docker provides us with many opportunities for performance tuning, such as:

• Reduce image size : Image size has a direct impact on container startup time and network transfer speed. We can reduce image size by using multi-stage builds, choosing an appropriate base image, and cleaning up useless files.

• Optimize container resources : In a Docker container, we can set the resource limits and priorities of the container such as CPU, memory, and disk. We need to configure container resources according to the characteristics and load of the application.

• Use inter-container communication : In a full-stack application, different containers need to communicate with each other. We can use the Docker network to achieve inter-container communication, and we can choose different network types and protocols, such as bridge network, overlay network and Overlay network.

• Persistent data storage : In a Docker container, the file system is temporary, and all data will be lost after the container is restarted. Therefore, we need to use persistent storage to save data, such as using local volumes or network storage, to ensure data reliability and durability.

To sum up, using Docker containers to deploy applications can help us carry out full-stack development more conveniently, and we can also use Docker containers for performance tuning and optimization. We need to understand the basics of Docker containers, use docker-compose to manage the running status of multiple containers, and perform performance tuning according to the needs of specific applications.

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