api: fix validation and http response

internal/api/v1/utils/error.go

@@ -4,6 +4,7 @@ import (
 	"net/http"
 
 	E "github.com/yusing/go-proxy/internal/error"
+	"github.com/yusing/go-proxy/internal/utils/strutils/ansi"
 )
 
 // HandleErr logs the error and returns an HTTP error response to the client.
@@ -23,6 +24,13 @@ func HandleErr(w http.ResponseWriter, r *http.Request, origErr error, code ...in
 	http.Error(w, http.StatusText(statusCode), statusCode)
 }
 
+func RespondError(w http.ResponseWriter, err error, code ...int) {
+	if len(code) > 0 {
+		w.WriteHeader(code[0])
+	}
+	WriteBody(w, []byte(ansi.StripANSI(err.Error())))
+}
+
 func ErrMissingKey(k string) error {
 	return E.New("missing key '" + k + "' in query or request body")
 }