Ginoauth — OAuth2 Library for Gin in Go

ginoauth is a Go library that simplifies the integration of OAuth2 authentication into applications built with the Gin web framework. It supports providers such as Google and Casdoor.

Features

• Easy OAuth2 authentication integration with Gin.
• Support for multiple providers (Google, Casdoor).
• Token and user data stored in signed and compressed cookies.
• Token refresh mechanism for expired tokens.
• Fetching user information from the provider.
• Flexible hooks: OnAuthenticateSuccess, OnUpdateUserInfo.

---

Installation

go get github.com/nullpointerfan/gin-oauth

---

Quick Start

1. Configure the Client

For Google:

import (
	"github.com/nullpointerfan/gin-oauth"
)

cfg := ginoauth.GoogleConfig{
	OAuthConfig: ginoauth.OAuthConfig{
		ClientID:     "your-google-client-id",
		ClientSecret: "your-google-client-secret",
		RedirectURL:  "http://localhost:8080/auth/callback",
		Secret:       []byte("your-jwt-secret"),
	},
}

auth := ginoauth.NewGoogleAuth(cfg)

For Casdoor:

cfg := ginoauth.CasdoorConfig{
	OAuthConfig: ginoauth.OAuthConfig{
		ClientID:     "casdoor-client-id",
		ClientSecret: "casdoor-client-secret",
		RedirectURL:  "http://localhost:8080/auth/callback",
		Secret:       []byte("your-jwt-secret"),
	},
	CasdoorHost: "https://your-casdoor-host",
}

auth := ginoauth.NewCasdoorAuth(cfg)

---

2. Setup Routes

r := gin.Default()

r.GET("/login", auth.LoginHandler)
r.GET("/auth/callback", auth.CallbackHandler)
r.GET("/logout", auth.LogoutHandler)

// Protected route
protected := r.Group("/")
protected.Use(auth.Authenticate)
{
	protected.GET("/profile", func(c *gin.Context) {
		user, _ := c.Get("user")
		c.JSON(200, gin.H{"user": user})
	})
}

---

Authentication

• OAuth2 tokens are stored in secure cookies with HMAC signature and gzip compression.
• When a token expires, it's automatically refreshed using the refresh_token.
• User information is also stored in cookies and can be extended via OnUpdateUserInfo.

---

Hooks

OnUpdateUserInfo

Called after receiving user data from the provider. Useful for adding custom fields or logic:

auth.OnUpdateUserInfo(func(userInfo *ginoauth.UserInfoResponse) error {
	userInfo.Name = strings.ToUpper(userInfo.Name)
	return nil
})

OnAuthenticateSuccess

Executed upon successful authentication:

auth.OnAuthenticateSuccess(func(c *gin.Context) error {
	c.Set("custom_user_data", "some_extra_info")
	return nil
})

---

Logout

To log out a user, simply call /logout:

r.GET("/logout", auth.LogoutHandler)

This will remove all session-related data (tokens and user info).