adding jwt tokens

backend/services/auth.go

@@ -0,0 +1,68 @@
+package services
+
+import (
+	"time"
+
+	"adam-french.co.uk/backend/models"
+	"github.com/golang-jwt/jwt/v5"
+)
+
+type Auth struct {
+	config *AuthConfig
+}
+
+type AuthConfig struct {
+	Secret []byte
+}
+
+type Tokens struct {
+	AccessToken  string
+	RefreshToken string
+}
+
+func InitAuth(config *AuthConfig) *Auth {
+	auth := Auth{config: config}
+
+	return &auth
+}
+
+func (auth *Auth) GenerateJWT(user *models.User) (*Tokens, error) {
+	accessToken := jwt.NewWithClaims(jwt.SigningMethodHS256, jwt.MapClaims{
+		"username": user.Username,
+		"id":       user.ID,
+		"admin":    user.Admin,
+		"exp":      time.Now().AddDate(0, 0, 1).Unix(),
+	})
+
+	refreshToken := jwt.NewWithClaims(jwt.SigningMethodHS256, jwt.MapClaims{
+		"id":  user.ID,
+		"exp": time.Now().AddDate(1, 0, 0).Unix(),
+	})
+
+	accessTokenString, err := accessToken.SignedString(auth.config.Secret)
+	if err != nil {
+		return nil, err
+	}
+
+	refreshTokenString, err := refreshToken.SignedString(auth.config.Secret)
+	if err != nil {
+		return nil, err
+	}
+
+	return &Tokens{AccessToken: accessTokenString, RefreshToken: refreshTokenString}, nil
+}
+
+func (auth *Auth) VerifyJWT(tokens Tokens) (*jwt.MapClaims, error) {
+	token, err := jwt.Parse(tokens.AccessToken, func(token *jwt.Token) (any, error) {
+		return auth.config.Secret, nil
+	}, jwt.WithValidMethods([]string{jwt.SigningMethodHS256.Alg()}))
+	if err != nil {
+		return nil, err
+	}
+
+	if claims, ok := token.Claims.(jwt.MapClaims); ok && token.Valid {
+		return &claims, nil
+	}
+
+	return nil, err
+}