feat(jwt): validating token

backend/jwt.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"errors"
 	"time"
 
 	"github.com/golang-jwt/jwt/v5"
@@ -20,6 +21,9 @@ type JwtClaims struct {
 	Expire time.Time
 }
 
+// obviously this is very not secure. TODO: extract to env
+var JWT_SECRET = []byte("very secret")
+
 func createToken(claims JwtClaims) *jwt.Token {
 	return jwt.NewWithClaims(jwt.SigningMethodHS256, jwt.MapClaims{
 		"UserID": claims.UserID,
@@ -36,7 +40,7 @@ func CreateRefreshToken(userId uuid.UUID) string {
 	})
 
 	// TODO: bruh what is this
-	tokenString, err := token.SignedString([]byte("very secret"))
+	tokenString, err := token.SignedString(JWT_SECRET)
 	if err != nil {
 		panic(err)
 	}
@@ -52,10 +56,41 @@ func CreateAccessToken(userId uuid.UUID) string {
 	})
 
 	// TODO: bruh what is this
-	tokenString, err := token.SignedString([]byte("very secret"))
+	tokenString, err := token.SignedString(JWT_SECRET)
 	if err != nil {
 		panic(err)
 	}
 
 	return tokenString
 }
+
+var NotValidToken = errors.New("Not a valid token")
+
+func GetUserIdFromAccess(accessToken string) (uuid.UUID, error) {
+	token, err := jwt.Parse(accessToken, func(token *jwt.Token) (any, error) {
+		return JWT_SECRET, nil
+	}, jwt.WithValidMethods([]string{jwt.SigningMethodHS256.Alg()}))
+
+	if err != nil {
+		return uuid.Nil, err
+	}
+
+	// Blah blah, check expiry and stuff
+
+	// this function is stupid
+	if claims, ok := token.Claims.(jwt.MapClaims); ok {
+		tokenType, ok := claims["Type"]
+		if !ok || tokenType.(string) != "access" {
+			return uuid.Nil, NotValidToken
+		}
+
+		userId, err := uuid.Parse(claims["UserID"].(string))
+		if err != nil {
+			return uuid.Nil, NotValidToken
+		}
+
+		return userId, nil
+	} else {
+		return uuid.Nil, NotValidToken
+	}
+}

backend/main.go

@@ -63,9 +63,19 @@ func main() {
 	})
 
 	r.Get("/image", func(w http.ResponseWriter, r *http.Request) {
-		userId := r.Header.Get("userId")
+		token := r.Header.Get("Authorization")[7:]
 
-		images, err := userModel.ListWithProperties(r.Context(), uuid.MustParse(userId))
+		fmt.Println(token)
+
+		userId, err := GetUserIdFromAccess(token)
+		if err != nil {
+			log.Println(err)
+			w.WriteHeader(http.StatusForbidden)
+			fmt.Fprintf(w, "Get out of here!")
+			return
+		}
+
+		images, err := userModel.ListWithProperties(r.Context(), userId)
 		if err != nil {
 			log.Println(err)
 			w.WriteHeader(http.StatusNotFound)