Go Token - Golang HTTP Application for JWT Authentication

Go Token is a simple Golang HTTP application that provides endpoints for generating and verifying JSON Web Tokens (JWT) for user authentication.

This Go application provides token management functionalities, including token generation, token verification, and token destruction. It uses JSON Web Tokens (JWTs) to secure your endpoints and manage user sessions.

Prerequisites

Before running this application, make sure you have the following prerequisites installed on your system:

• Go (Golang): You can download and install Go from https://golang.org/dl/.

Getting Started

1. Clone the repository:

   git clone https://github.com/ahmedMHasan/go-token.git
   cd go-token

2. Install the required packages by running:

   go get github.com/dgrijalva/jwt-go

3. Build and run the project:

   go run main.go

The application will start and listen on port 8080.

Endpoints

Generate Token

• Endpoint: /generateToken

• Method: POST

• Description: Generates a JWT token for a specified username.

• Usage: Send a POST request to this endpoint with a JSON body containing the username and password for the user you want to authenticate. The endpoint will return a JWT token along with its expiration time.

  Example using cURL:

  curl -X POST -d '{"username": "your_username", "password": "your_password"}' http://localhost:8080/generateToken

Verify Token

• Endpoint: /verifyToken

• Method: GET

• Description: Verifies the JWT token provided in the request header.

• Usage: Access this endpoint with a valid JWT token in the "Token" header to check if the token is valid. It will return "Logged In" if the token is valid; otherwise, it will return "Unauthorized."

  Example using cURL:

  curl -H "Token: your_jwt_token" http://localhost:8080/verifyToken

Destroy Token

• Endpoint: /destroyToken

• Method: POST

• Description: Terminates the session (token) based on the username and password.

• Usage: Send a POST request to this endpoint with a JSON body containing the username and password of the user for whom you want to destroy the token. If the provided credentials are correct, and a valid token exists for the user, the token will be destroyed, and subsequent requests with that token will be unauthorized.

  Example using cURL:

  curl -X POST -d '{"username": "your_username", "password": "your_password"}' http://localhost:8080/destroyToken

Token Management

• Tokens are generated with an expiration time of 1 Hour for demonstration purposes. You can modify the generateJWT function to set a different expiration time as needed.

• The application keeps track of the last valid token for each username. If a user generates a new token while a valid token exists, the application will return the last valid token along with its expiration time.

• To destroy a token, send a request to the /destroyToken endpoint with valid credentials. If the token is valid and matches the last valid token for the user, it will be destroyed.

Usage with Postman

1. Open Postman or any API testing tool.

2. Create a new request for each of the following endpoints:

   • Generate Token: Set the request URL to http://localhost:8080/generateToken, and send the request with a JSON body containing username and password. You will receive a JWT token in the response.

   • Verify Token: Set the request URL to http://localhost:8080/verifyToken. Add a header with the key "Token" and the value being the JWT token obtained from the "Generate Token" request. Send the request to verify the token.

   • Destroy Token: Set the request URL to http://localhost:8080/destroyToken. Send a POST request with a JSON body containing username and password to destroy the token for the specified user.

Project Structure

• main.go: The main Go source code file.
• README.md: This README file.
• .gitignore: Git ignore file.
• LICENSE: License information.

Contributing

Contributions are welcome! If you have any suggestions or find any issues, please open an issue or create a pull request.

License

This project is licensed under the MIT License. See the LICENSE file for details.

Acknowledgments

• Thanks to the authors of the github.com/dgrijalva/jwt-go library for their work on JWT token handling in Go.

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