authorizer/server/oauth/oauth.go

package oauth

import (
	"context"

	"github.com/coreos/go-oidc/v3/oidc"
	"golang.org/x/oauth2"
	facebookOAuth2 "golang.org/x/oauth2/facebook"
	githubOAuth2 "golang.org/x/oauth2/github"
	linkedInOAuth2 "golang.org/x/oauth2/linkedin"

	"github.com/authorizerdev/authorizer/server/constants"
	"github.com/authorizerdev/authorizer/server/memorystore"
)

// OAuthProviders is a struct that contains reference all the OAuth providers
type OAuthProvider struct {
	GoogleConfig   *oauth2.Config
	GithubConfig   *oauth2.Config
	FacebookConfig *oauth2.Config
	LinkedInConfig *oauth2.Config
	AppleConfig    *oauth2.Config
	TwitterConfig  *oauth2.Config
}

// OIDCProviders is a struct that contains reference all the OpenID providers
type OIDCProvider struct {
	GoogleOIDC *oidc.Provider
}

var (
	// OAuthProviders is a global variable that contains instance for all enabled the OAuth providers
	OAuthProviders OAuthProvider
	// OIDCProviders is a global variable that contains instance for all enabled the OpenID providers
	OIDCProviders OIDCProvider
)

// InitOAuth initializes the OAuth providers based on EnvData
func InitOAuth() error {
	ctx := context.Background()
	googleClientID, err := memorystore.Provider.GetStringStoreEnvVariable(constants.EnvKeyGoogleClientID)
	if err != nil {
		googleClientID = ""
	}
	googleClientSecret, err := memorystore.Provider.GetStringStoreEnvVariable(constants.EnvKeyGoogleClientSecret)
	if err != nil {
		googleClientSecret = ""
	}
	if googleClientID != "" && googleClientSecret != "" {
		p, err := oidc.NewProvider(ctx, "https://accounts.google.com")
		if err != nil {
			return err
		}
		OIDCProviders.GoogleOIDC = p
		OAuthProviders.GoogleConfig = &oauth2.Config{
			ClientID:     googleClientID,
			ClientSecret: googleClientSecret,
			RedirectURL:  "/oauth_callback/google",
			Endpoint:     OIDCProviders.GoogleOIDC.Endpoint(),
			Scopes:       []string{oidc.ScopeOpenID, "profile", "email"},
		}
	}

	githubClientID, err := memorystore.Provider.GetStringStoreEnvVariable(constants.EnvKeyGithubClientID)
	if err != nil {
		githubClientID = ""
	}
	githubClientSecret, err := memorystore.Provider.GetStringStoreEnvVariable(constants.EnvKeyGithubClientSecret)
	if err != nil {
		githubClientSecret = ""
	}
	if githubClientID != "" && githubClientSecret != "" {
		OAuthProviders.GithubConfig = &oauth2.Config{
			ClientID:     githubClientID,
			ClientSecret: githubClientSecret,
			RedirectURL:  "/oauth_callback/github",
			Endpoint:     githubOAuth2.Endpoint,
		}
	}

	facebookClientID, err := memorystore.Provider.GetStringStoreEnvVariable(constants.EnvKeyFacebookClientID)
	if err != nil {
		facebookClientID = ""
	}
	facebookClientSecret, err := memorystore.Provider.GetStringStoreEnvVariable(constants.EnvKeyFacebookClientSecret)
	if err != nil {
		facebookClientSecret = ""
	}
	if facebookClientID != "" && facebookClientSecret != "" {
		OAuthProviders.FacebookConfig = &oauth2.Config{
			ClientID:     facebookClientID,
			ClientSecret: facebookClientSecret,
			RedirectURL:  "/oauth_callback/facebook",
			Endpoint:     facebookOAuth2.Endpoint,
			Scopes:       []string{"public_profile", "email"},
		}
	}

	linkedInClientID, err := memorystore.Provider.GetStringStoreEnvVariable(constants.EnvKeyLinkedInClientID)
	if err != nil {
		linkedInClientID = ""
	}
	linkedInClientSecret, err := memorystore.Provider.GetStringStoreEnvVariable(constants.EnvKeyLinkedInClientSecret)
	if err != nil {
		linkedInClientSecret = ""
	}
	if linkedInClientID != "" && linkedInClientSecret != "" {
		OAuthProviders.LinkedInConfig = &oauth2.Config{
			ClientID:     linkedInClientID,
			ClientSecret: linkedInClientSecret,
			RedirectURL:  "/oauth_callback/linkedin",
			Endpoint:     linkedInOAuth2.Endpoint,
			Scopes:       []string{"r_liteprofile", "r_emailaddress"},
		}
	}

	appleClientID, err := memorystore.Provider.GetStringStoreEnvVariable(constants.EnvKeyAppleClientID)
	if err != nil {
		appleClientID = ""
	}
	appleClientSecret, err := memorystore.Provider.GetStringStoreEnvVariable(constants.EnvKeyAppleClientSecret)
	if err != nil {
		appleClientSecret = ""
	}
	if appleClientID != "" && appleClientSecret != "" {
		OAuthProviders.AppleConfig = &oauth2.Config{
			ClientID:     appleClientID,
			ClientSecret: appleClientSecret,
			RedirectURL:  "/oauth_callback/apple",
			Endpoint: oauth2.Endpoint{
				AuthURL:  "https://appleid.apple.com/auth/authorize",
				TokenURL: "https://appleid.apple.com/auth/token",
			},
		}
	}

	twitterClientID, err := memorystore.Provider.GetStringStoreEnvVariable(constants.EnvKeyTwitterClientID)
	if err != nil {
		twitterClientID = ""
	}
	twitterClientSecret, err := memorystore.Provider.GetStringStoreEnvVariable(constants.EnvKeyTwitterClientSecret)
	if err != nil {
		twitterClientSecret = ""
	}
	if twitterClientID != "" && twitterClientSecret != "" {
		OAuthProviders.TwitterConfig = &oauth2.Config{
			ClientID:     twitterClientID,
			ClientSecret: twitterClientSecret,
			RedirectURL:  "/oauth_callback/twitter",
			Endpoint: oauth2.Endpoint{
				// Endpoint is currently not yet part of oauth2-package. See https://go-review.googlesource.com/c/oauth2/+/350889 for status
				AuthURL:   "https://twitter.com/i/oauth2/authorize",
				TokenURL:  "https://api.twitter.com/2/oauth2/token",
				AuthStyle: oauth2.AuthStyleInHeader,
			},
			Scopes: []string{"tweet.read", "users.read"},
		}
	}

	return nil
}