token_generator

Token Generator Example

This example demonstrates how to use the TokenGenerator functionality to create JWT tokens directly without using HTTP middleware handlers.

Features

• Direct Token Generation: Generate complete token pairs (access + refresh) programmatically
• Refresh Token Management: Handle refresh token rotation and revocation
• RFC 6749 Compliant: Follows OAuth 2.0 standards for token management
• No HTTP Required: Generate tokens without needing HTTP requests

Usage

Run the example:

cd _example/token_generator
go run main.go

Key Methods

TokenGenerator(userData any) (*core.Token, error)

Generates a complete token pair containing:

• Access token (JWT)
• Refresh token (opaque)
• Token metadata (expiry, creation time, etc.)

tokenPair, err := authMiddleware.TokenGenerator(userData)
if err != nil {
    log.Fatal("Failed to generate token pair:", err)
}

fmt.Printf("Access Token: %s\n", tokenPair.AccessToken)
fmt.Printf("Refresh Token: %s\n", tokenPair.RefreshToken)
fmt.Printf("Expires In: %d seconds\n", tokenPair.ExpiresIn())

TokenGeneratorWithRevocation(userData any, oldRefreshToken string) (*core.Token, error)

Generates a new token pair and automatically revokes the old refresh token:

newTokenPair, err := authMiddleware.TokenGeneratorWithRevocation(userData, oldRefreshToken)
if err != nil {
    log.Fatal("Failed to refresh token pair:", err)
}

Token Structure

The core.Token struct contains:

type Token struct {
    AccessToken  string `json:"access_token"`   // JWT access token
    TokenType    string `json:"token_type"`     // Always "Bearer"
    RefreshToken string `json:"refresh_token"`  // Opaque refresh token
    ExpiresAt    int64  `json:"expires_at"`     // Unix timestamp
    CreatedAt    int64  `json:"created_at"`     // Unix timestamp
}

Utility Methods

• ExpiresIn() - Returns seconds until token expires
• Server-side refresh token storage and validation
• Automatic token rotation on refresh

Use Cases

1. Programmatic Authentication: Generate tokens for service-to-service communication
2. Testing: Create tokens for testing authenticated endpoints
3. Registration Flow: Issue tokens immediately after user registration
4. Background Jobs: Generate tokens for background processing
5. Custom Authentication: Build custom authentication flows

Security Features

• Refresh Token Rotation: Old tokens are automatically revoked
• Server-side Storage: Refresh tokens are stored securely server-side
• Expiry Management: Both access and refresh tokens have proper expiry
• RFC 6749 Compliance: Follows OAuth 2.0 security standards