Detailed explanation of examples of Golang implementing JWT authentication

Preface

JWT (JSON Web Token) is an open standard (RFC 7519) used to securely transmit claims between network applications. It can guarantee the integrity of the statement through digital signature or encryption and is often used to pass identity information between the user and the server. In Golang, the generation, signature and verification of JWTs can be easily implemented by using third-party libraries. This article will introduce how to implement the basic functionality of JWT using Golang and provides a simple example code.

What is JWT

A JWT is a string consisting of three parts separated by dots:

• Header: Contains metadata of the token, such as type (JWT) and the algorithm used (such as HMAC SHA256 or RSA).
• Payload: contains claims, which are some declarative information about entities (usually users) and other data.
• Signature: Signature Header and Payload using a key to ensure data integrity.

JWT is often used to perform secure transmissions in terms of authentication and information exchange. Its advantages include ease of transmission, self-containment, ease of parsing and use.

Using JWT in Golang

In Golang, we can use third-party libraries to easily implement JWT generation, signature and verification functions. In this article, we will use/golang-jwt/jwt/v5This library is implemented.

First, we need to import the library:

import (
	"fmt"
	"time"
	jwt "/golang-jwt/jwt/v5"
)

Next, we define a structureJWTInstance, used to initialize the JWT instance and store the key:

type JWTInstance struct {
	SecretKey []byte
}

Then, we implement the method of initializing the JWT instance and generating the JWT:

func InitJwt(SecretKey []byte) JWTInstance {
	return JWTInstance{SecretKey}
}

// GenerateJWT GenerateJWTfunc (that JWTInstance) GenerateJWT(username string, count ) string {
	// Create a new JWT token	jwtToken := (jwt.SigningMethodHS256)
	// Set some declarations	claims := .()
	claims["username"] = username
	claims["exp"] = ().Add( * count).Unix()

	// Set the signature and get the token string	token, err := ()
	if err != nil {
		return ""
	}
	return token
}

Finally, we implement the method of parsing JWT:

// ParseJWT parses JWTfunc (that JWTInstance) ParseJWT(tokenString string)  {
	// parse JWT strings	token, err := (tokenString, func(token *) (interface{}, error) {
		return , nil
	})

	if err != nil {
		return nil
	}

	// Verify token	if claims, ok := .(); ok &&  {
		return claims
	}

	return nil
}

Sample code

Here is a simple example code that demonstrates how to initialize a JWT instance and generate and parse a JWT:

func TestJwt() {
	jwt := InitJwt([]byte("2024/3/23"))
	token := ("example_user", 24) // Generate JWT with a validity period of 24 hours	(token)

	claims := (token)
	(claims)
}

in conclusion

In this article, we introduce the basic concepts of JWT and the method of implementing JWT in Golang using third-party libraries. By using JWT, we can safely transmit claims between network applications and implement authentication and information exchange functions. In actual development, JWT can be customized to configure and use according to requirements to meet specific business needs.

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