diff --git a/fix.go b/fix.go
new file mode 100644
index 0000000..50eacee
--- /dev/null
+++ b/fix.go
@@ -0,0 +1,14 @@
+package fix
+
+import "net/url"
+
+// FixURLParameterLoss preserves URL parameters when path is rewritten
+// by cloning the original query values before modification.
+func PreserveQueryParams(originalURL *url.URL) url.Values {
+    params := make(url.Values)
+    for k, v := range originalURL.Query() {
+        params[k] = make([]string, len(v))
+        copy(params[k], v)
+    }
+    return params
+}