api: fix validation and http response

internal/api/v1/utils/utils.go

@@ -6,6 +6,7 @@ import (
 	"net/http"
 
 	"github.com/yusing/go-proxy/internal/logging"
+	"github.com/yusing/go-proxy/internal/utils/strutils/ansi"
 )
 
 func WriteBody(w http.ResponseWriter, body []byte) {
@@ -27,13 +28,17 @@ func RespondJSON(w http.ResponseWriter, r *http.Request, data any, code ...int)
 		j = []byte(fmt.Sprintf("%q", data))
 	case []byte:
 		j = data
+	case error:
+		j, err = json.Marshal(ansi.StripANSI(data.Error()))
 	default:
 		j, err = json.MarshalIndent(data, "", "  ")
-		if err != nil {
-			logging.Panic().Err(err).Msg("failed to marshal json")
-			return false
-		}
 	}
+
+	if err != nil {
+		logging.Panic().Err(err).Msg("failed to marshal json")
+		return false
+	}
+
 	_, err = w.Write(j)
 	if err != nil {
 		HandleErr(w, r, err)