x/auth/login.go

// routes/login/login.go

package auth

import (
	"crypto/rand"
	"encoding/base64"
	"net/http"
)

func NewLoginHandler(c Config) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		// Generate random state
		b := make([]byte, 32)
		_, err := rand.Read(b)
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}
		state := base64.StdEncoding.EncodeToString(b)

		session, err := Store.Get(r, SessionName)
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}
		session.Values["state"] = state
		err = session.Save(r, w)
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}

		authenticator, err := NewAuthenticator(c.Domain, c.ClientID, c.ClientSecret, c.CallbackURL)
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}

		http.Redirect(w, r, authenticator.Config.AuthCodeURL(state), http.StatusTemporaryRedirect)
	}

}