OliveTin/internal/httpservers/restapi_auth_jwt.go

package httpservers

import (
	"errors"
	"fmt"
	"github.com/golang-jwt/jwt/v4"
	log "github.com/sirupsen/logrus"
	"net/http"
)

func parseJwtToken(cookieValue string) (*jwt.Token, error) {
	return jwt.Parse(cookieValue, func(token *jwt.Token) (interface{}, error) {
		// Don't forget to validate the alg is what you expect:
		if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
			return nil, fmt.Errorf("unexpected signing method: %v", token.Header["alg"])
		}

		// hmacSampleSecret is a []byte containing your secret, e.g. []byte("my_secret_key")
		return []byte(cfg.AuthJwtSecret), nil
	})
}

func getClaimsFromJwtToken(cookieValue string) (jwt.MapClaims, error) {
	token, err := parseJwtToken(cookieValue)

	if err != nil {
		log.Errorf("jwt parse failure: %v", err)
		return nil, errors.New("jwt parse failure")
	}

	if claims, ok := token.Claims.(jwt.MapClaims); ok && token.Valid {
		return claims, nil
	} else {
		return nil, errors.New("jwt token isn't valid")
	}
}

func lookupClaimValueOrDefault(claims jwt.MapClaims, key string, def string) string {
	if val, ok := claims[key]; ok {
		return fmt.Sprintf("%s", val)
	} else {
		return def
	}
}

func parseJwtCookie(request *http.Request) (string, string) {
	cookie, err := request.Cookie(cfg.AuthJwtCookieName)

	if err != nil {
		log.Debugf("jwt cookie check %v name: %v", err, cfg.AuthJwtCookieName)
		return "", ""
	}

	claims, err := getClaimsFromJwtToken(cookie.Value)

	log.Debugf("jwt claims data: %+v", claims)

	if err != nil {
		log.Warnf("jwt claim error: %+v", err)
		return "", ""
	}

	username := lookupClaimValueOrDefault(claims, cfg.AuthJwtClaimUsername, "")
	usergroup := lookupClaimValueOrDefault(claims, cfg.AuthJwtClaimUserGroup, "")

	return username, usergroup
}