Middlewares and some string util functions refactored. Added partial Documentation.

internal/strings.go

@@ -0,0 +1,19 @@
+package internal
+
+// PreferFirst returns first non-empty string
+func PreferFirst(first string, second string) string {
+	if first != "" {
+		return first
+	}
+	return second
+}
+
+// Contains checks whether []string Contains string
+func Contains(s []string, e string) bool {
+	for _, a := range s {
+		if a == e {
+			return true
+		}
+	}
+	return false
+}