init

internal/urlrewrite/rewrite.go

@@ -0,0 +1,65 @@
+package urlrewrite
+
+import "encoding/json"
+
+func rewriteStringValue(input, oldPrefix, newPrefix string) (string, bool) {
+	if oldPrefix == "" || newPrefix == "" {
+		return input, false
+	}
+	if len(input) >= len(oldPrefix) && input[:len(oldPrefix)] == oldPrefix {
+		return newPrefix + input[len(oldPrefix):], true
+	}
+	return input, false
+}
+
+func rewriteJSONContent(input, oldPrefix, newPrefix string) (string, bool, error) {
+	var data any
+	if err := json.Unmarshal([]byte(input), &data); err != nil {
+		rewritten, changed := rewriteStringValue(input, oldPrefix, newPrefix)
+		if changed {
+			return rewritten, true, nil
+		}
+		return "", false, err
+	}
+	rewritten, changed := rewriteAny(data, oldPrefix, newPrefix)
+	if !changed {
+		return input, false, nil
+	}
+	out, err := json.Marshal(rewritten)
+	if err != nil {
+		return "", false, err
+	}
+	return string(out), true, nil
+}
+
+func rewriteAny(value any, oldPrefix, newPrefix string) (any, bool) {
+	switch v := value.(type) {
+	case map[string]any:
+		changed := false
+		for key, child := range v {
+			newChild, childChanged := rewriteAny(child, oldPrefix, newPrefix)
+			if childChanged {
+				v[key] = newChild
+				changed = true
+			}
+		}
+		return v, changed
+	case []any:
+		changed := false
+		for i, child := range v {
+			newChild, childChanged := rewriteAny(child, oldPrefix, newPrefix)
+			if childChanged {
+				v[i] = newChild
+				changed = true
+			}
+		}
+		return v, changed
+	case string:
+		if rewritten, changed, err := rewriteJSONContent(v, oldPrefix, newPrefix); err == nil && changed {
+			return rewritten, true
+		}
+		return rewriteStringValue(v, oldPrefix, newPrefix)
+	default:
+		return value, false
+	}
+}