The basics of Python web asynchronous programming

As web applications continue to grow and increase in complexity, asynchronous programming for the web is becoming more and more popular. Python is a highly extensible programming language, and large-scale web applications have been widely written using Python frameworks, such as Django and Flask. However, for asynchronous web programming, Python actually has many problems in handling high concurrency and I/O-intensive tasks, but not all Python frameworks can solve these problems. Therefore, some new Python frameworks have emerged, such as Tornado and Aiohttp, specifically designed to handle asynchronous programming.

This article will introduce the basic knowledge of Python asynchronous programming and its application in web development. We'll explore:

1. What is asynchronous programming?
2. Two implementation methods of asynchronous programming in Python
3. Advantages of Python asynchronous programming
4. Comparison and application of Python asynchronous framework
5. What is asynchronous programming?

Asynchronous programming refers to separating the I/O operations and calculations of the computer system so that you can perform another operation without waiting for one operation to complete. Ordinary I/O operations will wait until the operation is completed, which wastes a lot of valuable time. The benefit of asynchronous programming is that it can effectively use CPU resources, while reducing waiting time and improving system performance.

In Python, asynchronous programming is implemented through asynchronous IO. Asynchronous IO means that when performing input and output operations, it does not block the execution of the CPU or other processes, but runs other operations before these operations are completed. The characteristic of asynchronous IO is that it uses callback functions or coroutines to notify the program and give a result before an operation is completed. These results can be called immediately by the waiting thread or processor.

2. Two ways to implement asynchronous programming in Python

(1) Callback function:

The callback function is a special function whose purpose is to achieve elegant code writing in asynchronous programming. The callback function is usually called after the operation is completed in order to process the returned results. In Python, there are many modules that support callback function-based asynchronous IO, such as Twisted and Asyncio.

(2) Coroutine:

Coroutine is a lightweight thread, that is, there can be multiple tasks using coroutines in a process, and coroutines can be executed to a certain Pause at one point, the coroutine will not continue execution until the program executing the coroutine explicitly resumes the coroutine. Python 3.5 and later introduced the async/await syntax, and Python's coroutine module has been greatly improved. These functions have become part of the standard library of Python 3.5 and are widely used in web development.

3. Advantages of Python asynchronous programming

One of the major advantages of Python asynchronous programming is that when handling a large number of concurrent connection requests, you can avoid using thread or process resources to handle I /O events, thus greatly saving CPU resources and memory overhead. The asynchronous programming I/O model is suitable for web applications, especially for input and output intensive applications, the asynchronous I/O model is particularly useful.

In addition, because asynchronous programming allows multiple tasks to be performed simultaneously and to switch between these tasks, asynchronous programming is more responsive and allows users to obtain results more quickly and reliably.

4. Comparison and application of Python asynchronous framework

Python asynchronous framework mainly includes Tornado and Aiohttp, both of which focus on I/O-intensive production environments Application development, all with high scalability and performance.

Tornado is a high-performance asynchronous programming framework. Node.js-style asynchronous code is easy to use and supports asynchronous HTTP clients and servers. It comes with a simple web service that can customize the web Application functionality. The characteristic of Tornado is that it uses a single-threaded, non-blocking programming model to handle requests, which is very useful for handling IO-intensive tasks.

Aiohttp is a pure Python asynchronous framework for building web applications and HTTP clients. This Python framework uses asynchronous traffic to make web services more responsive and allows developers to define asynchronous code using standard functions and syntax. This makes Aiohttp suitable for handling high concurrency and I/O intensive tasks.

Summary:

Python is now a very popular programming language and has been widely adopted by many developers because it is highly flexible, scalable and meets the development needs of web applications.

Python asynchronous programming is an implementation method used by the Python framework. It implements asynchronous processing technology, which can effectively use system resources, while reducing waiting time and improving system performance.

Python’s asynchronous frameworks mainly include Tornado and Aiohttp, both of which have excellent performance and scalability and are widely used in building high-performance web applications and processing I/O-intensive tasks.

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