Function Example_sanitizeStrings

reflect/protorange/example_test.go:232–307

Scan all protobuf string values for a sensitive word and replace it with a suitable alternative.

()

// Scan all protobuf string values for a sensitive word and replace it with
// a suitable alternative.
func Example_sanitizeStrings() {
	m := &newspb.Article{
		Author:  "Hermione Granger",
		Date:    timestamppb.New(time.Date(1998, time.May, 2, 0, 0, 0, 0, time.UTC)),
		Title:   "Harry Potter vanquishes Voldemort once and for all!",
		Content: "In a final duel between Harry Potter and Lord Voldemort earlier this evening...",
		Tags:    []string{"HarryPotter", "LordVoldemort"},
		Attachments: []*anypb.Any{{
			TypeUrl: "google.golang.org.KeyValueAttachment",
			Value: mustMarshal(&newspb.KeyValueAttachment{
				Name: "aliases.txt",
				Data: map[string]string{
					"Harry Potter": "The Boy Who Lived",
					"Tom Riddle":   "Lord Voldemort",
				},
			}),
		}},
	}

	protorange.Range(m.ProtoReflect(), func(p protopath.Values) error {
		const (
			sensitive   = "Voldemort"
			alternative = "[He-Who-Must-Not-Be-Named]"
		)

		// Check if there is a sensitive word to redact.
		last := p.Index(-1)
		s, ok := last.Value.Interface().(string)
		if !ok || !strings.Contains(s, sensitive) {
			return nil
		}
		s = strings.Replace(s, sensitive, alternative, -1)

		// Store the redacted string back into the message.
		beforeLast := p.Index(-2)
		switch last.Step.Kind() {
		case protopath.FieldAccessStep:
			m := beforeLast.Value.Message()
			fd := last.Step.FieldDescriptor()
			m.Set(fd, protoreflect.ValueOfString(s))
		case protopath.ListIndexStep:
			ls := beforeLast.Value.List()
			i := last.Step.ListIndex()
			ls.Set(i, protoreflect.ValueOfString(s))
		case protopath.MapIndexStep:
			ms := beforeLast.Value.Map()
			k := last.Step.MapIndex()
			ms.Set(k, protoreflect.ValueOfString(s))
		}
		return nil
	})

	fmt.Println(protojson.Format(m))

	// Output:
	// {
	//   "author": "Hermione Granger",
	//   "date": "1998-05-02T00:00:00Z",