tamnd/gauth

Clean authentication for Go

GAuth

Clean way to write authentication for Go.

This package was inspired by https://github.com/intridea/omniauth (written in Ruby) and http://github.com/markbates/goth (written in Go).

Features

• Support both OAuth 1.0a and OAuth2
• Have a long list of providers and is easy to write new ones.

Install

$ go get github.com/tamnd/gauth

List of Providers

Here are the list of supported providers. Would you love to see more providers? Feel free to contribute ones by create your own repository or create pull requests!

I use the list as reference. When porting providers directly from those gems, I also keep the author of the gems as author of the providers.

Please keep the list in alphabetical order

Provider	Description	Author	Is Official?
AngelList	Authenticate to AngelList using OAuth2.	railsjedi	No
Aol	Authenticate to Aol using OAuth2.	pianosnake	No
App.net	Authenticate to App.net using OAuth2.	phuu	No
Behance	Authenticate to Behance using OAuth2.	sandboxws	No
Box	Authenticate to Box using OAuth2.	iCoreTech, Inc.	No
Dropbox	Authenticate to Dropbox using OAuth2.	bamorim	No
Facebook	Authenticate to Facebook using OAuth2.	tamnd	No
Foursquare	Authenticate to Foursquare using OAuth2.	arunagw	No
Instagram	Authenticate to Instagram using OAuth2.	tamnd	No
Meetup	Authenticate to Meetup using OAuth2.	tapster	No

Usage

First, import GAuth and create OAuth provider

import (
	"github.com/tamnd/gauth"
	"github.com/tamnd/gauth/provider/facebook"
)

// Create facebook provider
var provider = facebook.New("FACEBOOK_KEY", "FACEBOOK_CLIENT_SECRET", "http://localhost:8080/auth/facebook/callback")

Next, define a handler for GET /auth/facebook. This will redirect the user to the facebook login page.

func login(w http.ResponseWriter, r *http.Request) {
	authURL, _, err := provider.AuthURL("state")
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	http.Redirect(w, r, authURL, http.StatusTemporaryRedirect)
}

Then define the handler for callback request at /auth/facebook/callback:

func callback(w http.ResponseWriter, r *http.Request) {
	code := r.URL.Query().Get("code")

	// Get access token from verification code.
	token, err := provider.Authorize(code)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

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

	// Marshal user info and write to the response.
	output, _ := json.Marshal(user)
	w.Write([]byte(output))
}

Finally, we register those handlers and start the server:

func main() {
	fmt.Println("Start listening on :8080")

	http.Handle("/auth/facebook", http.HandlerFunc(login))
	http.Handle("/auth/facebook/callback", http.HandlerFunc(callback))
	http.ListenAndServe(":8080", nil)
}

See the full source code at examples/facebook.go.

Write new provider

Writing new provider is pretty easy. You just need to define OAuth endpoints:

package yoursite

import "github.com/tamnd/gauth/oauth2"

var Endpoint = oauth2.Endpoint{
	AuthURL:  "https://yoursite.com/oauth2/auth",
	TokenURL: "https://yoursite.com/oauth2/token",
}

and define a function User to get user info from an access token:

package yoursite

import "github.com/tamnd/gauth"

func User(token *gauth.AccessToken) (*gauth.User, error) {
	// Get the user info here...
}

For example, here is the Facebook Authentication Provider:

provider/facebook/facebook.go

package facebook

import (
	"github.com/tamnd/gauth"
	"github.com/tamnd/gauth/oauth2"
)

var Endpoint = oauth2.Endpoint{
	AuthURL:  "https://www.facebook.com/dialog/oauth",
	TokenURL: "https://graph.facebook.com/oauth/access_token",
}

func New(clientId string, secret string, callbackURL string, scopes ...string) gauth.Provider {
	provider := &oauth2.Provider{
		Endpoint: Endpoint,
		UserFn:   User,
	}
	provider.Init(clientId, secret, callbackURL)
	return provider
}

provider/facebook/user.go

package facebook

import (
	"net/url"

	"github.com/tamnd/gauth"
	"github.com/tamnd/httpclient"
)

var endpointProfile = "https://graph.facebook.com/me?fields=email,first_name,last_name,link,bio,id,name,picture,location"

func User(token *gauth.AccessToken) (*gauth.User, error) {
	URL := endpointProfile + "&access_token=" + url.QueryEscape(token.Token)

	u := struct {
		ID      string `json:"id"`
		Email   string `json:"email"`
		Bio     string `json:"bio"`
		Name    string `json:"name"`
		Link    string `json:"link"`
		Picture struct {
			Data struct {
				URL string `json:"url"`
			} `json:"data"`
		} `json:"picture"`
		Location struct {
			Name string `json:"name"`
		} `json:"location"`
	}{}

	err := httpclient.JSON(URL, &u)
	if err != nil {
		return nil, err
	}

	user := gauth.User{
		ID:          u.ID,
		Name:        u.Name,
		Email:       u.Email,
		Username:    u.Name,
		Location:    u.Location.Name,
		Description: u.Bio,
		Avatar:      u.Picture.Data.URL,
		Raw:         u,
	}

	return &user, nil
}

Contribute

• Fork repository
• Create a feature branch
• Open a new pull request
• Create an issue for bug report or feature request

Contact

• Nguyen Duc Tam
• [email protected]
• http://twitter.com/tamnd87

License

The MIT License (MIT). Please see LICENSE for more information.

Copyright (c) 2015 Nguyen Duc Tam, [email protected]