goauth

A comprehensive Go package that provides a unified interface for OAuth2 authentication across multiple providers. This package simplifies the integration of OAuth2 authentication in your Go applications by offering a consistent API for various OAuth2 providers.

Features

• Unified interface for all OAuth2 providers
• Easy-to-use API
• Type-safe implementation
• Extensive provider support
• Built-in token management
• Standardized user information
• Customizable scopes
• Error handling
• Token refresh support

Installation

go get -u github.com/mstgnz/goauth

Quick Start

Here's a simple example using GitHub OAuth2:

package main

import (
    "log"
    "net/http"
    "github.com/mstgnz/goauth/initialize"
    "golang.org/x/oauth2"
)

func main() {
    // Initialize the provider
    provider, err := initialize.NewProviderByName("github")
    if err != nil {
        log.Fatal(err)
    }

    // Configure the provider
    provider.SetClientId("your-client-id")
    provider.SetClientSecret("your-client-secret")
    provider.SetRedirectUrl("http://localhost:8080/callback")
    provider.SetScopes([]string{"read:user", "user:email"})

    // Setup login handler
    http.HandleFunc("/login", func(w http.ResponseWriter, r *http.Request) {
        url := provider.BuildAuthUrl("state", oauth2.AccessTypeOffline)
        http.Redirect(w, r, url, http.StatusTemporaryRedirect)
    })

    // Setup callback handler
    http.HandleFunc("/callback", func(w http.ResponseWriter, r *http.Request) {
        // Exchange code for token
        token, err := provider.FetchToken(r.URL.Query().Get("code"))
        if err != nil {
            http.Error(w, err.Error(), http.StatusInternalServerError)
            return
        }

        // Get user information
        user, err := provider.FetchUser(token)
        if err != nil {
            http.Error(w, err.Error(), http.StatusInternalServerError)
            return
        }

        log.Printf("Logged in user: %+v", user)
    })

    log.Fatal(http.ListenAndServe(":8080", nil))
}

Supported Providers

The package currently supports the following OAuth2 providers:

Provider	Documentation
Apple	Apple Developer
Discord	Discord Developer
Facebook	Facebook for Developers
Gitea	Gitea Developer
Gitee	Gitee Developer
GitHub	GitHub Developer
GitLab	GitLab Developer
Google	Google Identity Platform
Instagram	Instagram Graph API
Kakao	Kakao Developers
LiveChat	LiveChat API
Mailcow	Mailcow API
Microsoft	Microsoft Identity Platform
OIDC	OpenID Connect
Patreon	Patreon API
Spotify	Spotify for Developers
Strava	Strava API
Twitch	Twitch Developers
X (Twitter)	X Developer
VK	VK API
Yandex	Yandex Passport API

Advanced Usage

Custom Scopes

provider.SetScopes([]string{
    "read:user",
    "user:email",
    "custom:scope",
})

Token Refresh

newToken, err := provider.RefreshToken(oldToken)
if err != nil {
    log.Fatal(err)
}

Custom HTTP Client

client := provider.Client(token)
resp, err := client.Get("https://api.provider.com/endpoint")

Best Practices

1. Environment Variables: Store sensitive credentials in environment variables

   provider.SetClientId(os.Getenv("OAUTH_CLIENT_ID"))
   provider.SetClientSecret(os.Getenv("OAUTH_CLIENT_SECRET"))

2. State Parameter: Always validate the state parameter

   if r.URL.Query().Get("state") != expectedState {
       http.Error(w, "Invalid state parameter", http.StatusBadRequest)
       return
   }

3. Error Handling: Implement proper error handling

   if err := provider.ValidateConfig(); err != nil {
       log.Fatal("Configuration error:", err)
   }

Security Considerations

• Always use HTTPS in production
• Implement CSRF protection using the state parameter
• Store tokens securely
• Use environment variables for credentials
• Implement PKCE when available
• Keep scopes to minimum required
• Properly handle token expiration and refresh

Contributing

We welcome contributions! Please see CONTRIBUTING.md for guidelines.

License

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

Support

If you encounter any issues or have questions, please file an issue on the GitHub repository.