signet-backend/endpoints/login.go

package endpoints

import (
	"encoding/json"
	"net/http"
	"time"

	"github.com/golang-jwt/jwt/v4"
	"github.com/imosed/signet/auth"
	. "github.com/imosed/signet/data"
	"github.com/rs/zerolog/log"
	"github.com/spf13/viper"
)

type LoginResponse struct {
	Token *string `json:"token"`
}

func Login(w http.ResponseWriter, r *http.Request) {
	var req AuthenticationRequest
	err := json.NewDecoder(r.Body).Decode(&req)
	if err != nil {
		log.Error().Err(err).Msg("Failed to decode body in login attempt")
		return
	}

	var userData struct {
		ID         uint
		Password   string
		Privileges uint
	}

	var resp LoginResponse
	Db.Table("users").Select("id, password, privileges").
		Where("username = ?", req.Username).First(&userData)
	var passwordMatches bool
	passwordMatches, err = ComparePasswordAndHash(req.Password, userData.Password)
	if err != nil {
		log.Error().Err(err).Msg("Could not compare password to hash in login attempt")
		return
	}
	if !passwordMatches {
		resp.Token = nil
		err = json.NewEncoder(w).Encode(resp)
		if err != nil {
			log.Error().Err(err).Msg("Failed to deliver failed login attempt response")
		}
		return
	}

	token := jwt.NewWithClaims(jwt.SigningMethodHS256, &auth.Claims{
		Username:   req.Username,
		Privileges: userData.Privileges,
		RegisteredClaims: jwt.RegisteredClaims{
			ExpiresAt: jwt.NewNumericDate(time.Now().Add(10 * time.Hour)),
		},
	})

	secret := viper.GetString("app.secretKey")
	tokenString, err := token.SignedString([]byte(secret))
	if err != nil {
		log.Error().Err(err).Msg("Could not generate JWT token")
		return
	}
	resp.Token = &tokenString

	err = json.NewEncoder(w).Encode(resp)
	if err != nil {
		log.Error().Err(err).Msg("Could not deliver response in Login call")
	}
}