feat: add jwt

utils/jwt.go

@@ -0,0 +1,66 @@
+package utils
+
+import (
+	"fmt"
+	"nCovTrack-Backend/global"
+	"time"
+
+	"github.com/golang-jwt/jwt/v4"
+)
+
+var JWT_KEY = []byte(global.ServerSettings.Jwt.Secret)
+
+// Generate token for user
+// Return: token generated
+func GenerateToken(claims jwt.MapClaims) string {
+	claims["exp"] = time.Now().Add(15 * 24 * time.Hour).Unix()
+	claims["iat"] = time.Now().Unix()
+	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
+	tokenStr, err := token.SignedString(JWT_KEY)
+	if err != nil {
+		panic(err)
+	}
+	return tokenStr
+}
+
+// Renew user's token
+// tokenStr: user request token
+// Return:
+// 		BlankString: token is invalid or token is expired out of allowed time;
+//		OldToken: token is not need to renew;
+//		NewToekn: token is renew;
+func RenewToken(tokenStr string) string {
+	token, err := jwt.Parse(tokenStr, func(t *jwt.Token) (interface{}, error) {
+		return JWT_KEY, nil
+	})
+
+	// Token is invalid
+	switch err.(*jwt.ValidationError).Errors {
+	case jwt.ValidationErrorSignatureInvalid:
+		return ""
+	case jwt.ValidationErrorIssuedAt:
+		return ""
+	}
+
+	claims := token.Claims.(jwt.MapClaims)
+	expireAt := time.Unix(int64(claims["exp"].(float64)), 0)
+	expireDuration := expireAt.Sub(time.Now())
+
+	// Token is out of allow expire duration
+	if expireDuration.Hours() < float64(-global.ServerSettings.Jwt.RenewExpireDays*24) {
+		return ""
+	}
+	// Token not need renew
+	if expireDuration.Hours() > float64(global.ServerSettings.Jwt.RenewAheadDays*24) {
+		return tokenStr
+	}
+	fmt.Println(expireDuration)
+
+	claims["exp"] = time.Now().Add(15 * 24 * time.Hour).Unix()
+	token = jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
+	tokenStr, err = token.SignedString(JWT_KEY)
+	if err != nil {
+		panic(err)
+	}
+	return tokenStr
+}