Sample code for easy implementation of JWT authentication with Golang

JSON Web Tokens (JWT) is a popular security method used to represent statements between two parties. In the field of web applications, they are often used as a way to transfer identity information (declaration) from clients to servers. This tutorial will walk you through the implementation of the JWT authentication process in your Go application.

What is JWT

JSON Web Token (JWT) is a compact and URL-safe way to transfer declarations between two parties. The declaration in JWT is encoded as a JSON object and is digitally signed using JSON Web Signature (JWS).

The usual format of JWT is:

• Header: The header (xxxxx) is usually composed of two parts: the token type JWT and the signature algorithm.
• Load: The load (yyyyy) contains the statement. The statement is a statement about the subject (user).
• Signature: To create a signature (zzzzzzz) section, you need to sign with the encoded header, the encoded load, a key, and the algorithm specified in the header.

Go environment settings

First, you need a package for handling JWT in Go. We will use the /golang-jwt/jwt package. [1]

Generate JWT in Go

Let's create a function that generates JWT:

package main

import (
 "fmt"
 "/golang-jwt/jwt/v4"
 "time"
)
var mySigningKey = []byte("secretpassword")
func GenerateJWT() (string, error) {
 token := (jwt.SigningMethodHS256)
 claims := .()
 claims["authorized"] = true
 claims["user"] = "John Doe"
 claims["exp"] = ().Add( * 30).Unix()
 tokenString, err := (mySigningKey)
 if err != nil {
  ("Something went wrong: %s", ())
  return "", err
 }
 return tokenString, nil
}

Verify JWT in Go

Now, let's verify the JWT:

func ValidateToken(tokenString string) (*, error) {
 token, err := (tokenString, func(token *) (interface{}, error) {
  if _, ok := .(*); !ok {
   return nil, ("There was an error")
  }
  return mySigningKey, nil
 })

 if err != nil {
   return nil, err
 }
 return token, nil
}

Authentication using JWT in Go Web Application

Here is a simple example of integrating JWT generation and verification in Go's HTTP server:

package main

import (
 "fmt"
 "log"
 "net/http"
)

func HomePage(w , r *) {
 validToken, err := GenerateJWT()
 if err != nil {
  (w, ())
 }
 clientToken := ("Token")
 if clientToken != validToken {
  ()
  (w, "Token is not valid")
  return
 }
 (w, "Hello, World!")
}

func handleRequests() {
 ("/", HomePage)
 ((":9000", nil))
}

func main() {
 handleRequests()
}

Use this setting:

• The server creates a JWT when accessing the home page.
• To perform verification, the client needs to send the same JWT in the header "Token".
• This is just a basic example. In practical cases, you generate a token after logging in and check on every request that requires authentication.

JWT provides a powerful and flexible way to handle authentication and authorization in web applications. In Go, using packages like /golang-jwt/jwt[2], it is very simple to implement JWT-based authentication. But remember to always keep your signature keys private and use a secure approach in production applications, preferably RSA, for added security.

This is the article about the example code for using Golang to easily implement JWT authentication. For more relevant content on Go to implement JWT authentication, please search for my previous articles or continue browsing the following related articles. I hope everyone will support me in the future!