[Hot topic analysis] WebSocket detailed explanation, the ultimate weapon for real-time communication!

[Hot topic analysis] WebSocket detailed explanation, the ultimate weapon for real-time communication!

WebSocket is a protocol for full-duplex communication in web applications. It establishes persistent two-way communication between client and server through a single TCP connection, making real-time data exchange possible. This blog will comprehensively introduce the principles, characteristics, usage methods and practical application scenarios of WebSocket, and deeply explore the mysteries of WebSocket.

introduction

WebSocket is an important web technology, which solves the one-way communication limitation of the HTTP protocol, so that the server can actively push data to the client without the client continuously sending requests. This full-duplex communication capability is widely used in real-time communication, online games, stock market and other fields. This blog will introduce the principles, characteristics, usage methods and related cases of WebSocket in detail, and take you to understand and master WebSocket technology in depth.

WebSocket basics

What are WebSockets?

WebSocket is a protocol for full-duplex communication in web applications. It realizes real-time data exchange by establishing a persistent two-way connection between the client and the server. The WebSocket protocol is based on a TCP connection, is compatible with the HTTP protocol, and uses the HTTP protocol for handshaking. It is a lightweight, efficient, and fast way to communicate.

The development history of WebSocket

WebSocket was first proposed by Hixie as "WebSocket Protocol Version 0.1", and gradually improved and evolved in the subsequent development. Currently, the latest version of WebSocket is RFC 6455, which has become part of the HTML5 standard and is widely supported by major browsers.

Features of WebSocket

WebSocket has the following salient features:

• Full-duplex communication: Two-way communication can be carried out between the server and the client at the same time, without waiting for the process of request and response.
• Real-time performance: WebSocket adopts long-term connection method, which can transmit data in real time and has a fast response speed.
• Reduce network traffic: Compared with the HTTP protocol, WebSocket only needs one handshake when establishing a connection, reducing unnecessary network traffic.
• Cross-domain support: WebSocket supports cross-domain communication and can communicate between different domain names.
• Low latency: The real-time and high efficiency of WebSocket make it widely used in online games, online chat and other fields.

WebSocket principle analysis

WebSocket connection establishment process

The process of establishing a connection with WebSocket mainly includes the handshake phase and the data transmission phase. Specific steps are as follows:

1. The client sends a WebSocket handshake request to the server.
2. After receiving the request, the server returns a WebSocket handshake response.
3. After a successful handshake, a persistent two-way connection is established between the client and server.
4. Clients and servers can communicate in real time through this connection, sending data and receiving data.

WebSocket data frame

WebSocket uses data frames to transmit data, and each data frame contains an opcode, payload data, and other control information. The common opcodes are as follows:

• 0x00: Indicates that the data frame is a continuation frame, which is used to transmit the middle part of the fragmented message.
• 0x01: Indicates that the data frame is a text frame.
• 0x02: Indicates that the data frame is a binary frame.
• 0x08: Indicates that the data frame is a connection close frame.
• 0x09: Indicates that the data frame is a PING frame for heartbeat detection.
• 0x0A: Indicates that the data frame is a PONG frame, which is used to respond to the PING frame.

The relationship between WebSocket and HTTP

The WebSocket protocol is very similar to the HTTP protocol, but it is not a replacement protocol for HTTP. When WebSocket establishes a connection, it needs to shake hands through the HTTP protocol, but the subsequent data transmission stage no longer follows the HTTP protocol.

WebSocket application practice

Real-time chat application based on WebSocket

WebSocket is very suitable for implementing real-time chat applications. By establishing a WebSocket connection, chat messages can be sent and received in real time, avoiding the overhead of polling and short polling.

Stock quotes push based on WebSocket

WebSocket can realize real-time stock market push. The server pushes the latest stock market data to the client in real time, and the client can display the latest market information in time to provide a better user experience.

Online games based on WebSocket

The real-time and full-duplex communication characteristics of WebSocket make it very suitable for online game scenarios. The game server can push the game status and other players' operations to the client in real time, realizing the instant communication function of the multiplayer online game.

epilogue

Through this blog, we have comprehensively explored the principles, characteristics, usage methods and practical application scenarios of WebSocket. As a protocol for realizing full-duplex communication, WebSocket plays an important role in real-time communication, online games, stock market and other fields. An in-depth understanding and mastery of WebSocket technology is of great significance for improving the real-time and user experience of Web applications.