Files
ng-blog/backend/auth/login.go
2025-04-10 16:17:58 +02:00

103 lines
2.4 KiB
Go

package auth
import (
"encoding/json"
"errors"
"fmt"
"net/http"
"strings"
"time"
"git.schreifuchs.ch/schreifuchs/ng-blog/backend/model"
"github.com/golang-jwt/jwt/v5"
)
func Login(username, password string, secret []byte) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
var login model.Login
if err := json.NewDecoder(r.Response.Request.Body).Decode(&login); err != nil {
w.WriteHeader(http.StatusUnauthorized)
return
}
if login.Name == username && login.Password == password {
token, err := createJWT(secret)
if err != nil {
w.WriteHeader(http.StatusUnauthorized)
return
}
err = json.NewEncoder(w).Encode(&model.LoginResponse{
Token: token,
})
if err != nil {
w.WriteHeader(http.StatusUnauthorized)
return
}
w.WriteHeader(http.StatusOK)
return
}
}
}
func Authenticated(secret []byte) func(http.HandlerFunc) http.Handler {
return func(next http.HandlerFunc) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
// Our middleware logic goes here...
token, err := extractToken(r)
if err != nil {
w.WriteHeader(http.StatusUnauthorized)
return
}
err = validateJWT(token, secret)
if err != nil {
w.WriteHeader(http.StatusUnauthorized)
return
}
next(w, r)
})
}
}
func createJWT(secret []byte) (token string, err error) {
return jwt.NewWithClaims(jwt.SigningMethodHS512, jwt.MapClaims{
"exp": time.Now().Add(time.Hour * 24).Unix(),
}).SignedString(secret)
}
func validateJWT(tokenString string, secret []byte) (err error) {
token, err := jwt.Parse(tokenString, func(token *jwt.Token) (any, 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"])
}
return secret, nil
})
if err != nil {
return
}
if date, err := token.Claims.GetExpirationTime(); err == nil && date.After(time.Now()) {
return nil
}
return errors.New("JWT not valid")
}
func extractToken(r *http.Request) (token string, err error) {
tokenHeader := r.Header.Get("Authorization") // Grab the token from the header
if tokenHeader == "" {
err = errors.New("missing token")
return
}
token = strings.TrimPrefix(tokenHeader, "Bearer ")
if token == "" {
err = errors.New("malformed token")
}
return
}