Function New

middleware/idempotency/idempotency.go:45–182

New creates idempotency middleware that caches responses keyed by the configured idempotency header.

(config ...Config)

// New creates idempotency middleware that caches responses keyed by the
// configured idempotency header.
func New(config ...Config) fiber.Handler {
	// Set default config
	cfg := configDefault(config...)

	redactKeys := !cfg.DisableValueRedaction

	maskKey := func(key string) string {
		if redactKeys {
			return redactedKey
		}
		return key
	}

	keepResponseHeadersMap := make(map[string]struct{}, len(cfg.KeepResponseHeaders))
	for _, h := range cfg.KeepResponseHeaders {
		// CopyString is needed because utils.ToLower uses UnsafeString
		// and map keys must be immutable
		keepResponseHeadersMap[utilsstrings.ToLower(h)] = struct{}{}
	}

	maybeWriteCachedResponse := func(c fiber.Ctx, key string) (bool, error) {
		if val, err := cfg.Storage.GetWithContext(c, key); err != nil {
			return false, fmt.Errorf("failed to read response: %w", err)
		} else if val != nil {
			var res response
			if _, err := res.UnmarshalMsg(val); err != nil {
				return false, fmt.Errorf("failed to unmarshal response: %w", err)
			}

			_ = c.Status(res.StatusCode)

			for header, vals := range res.Headers {
				for _, val := range vals {
					c.RequestCtx().Response.Header.Add(header, val)
				}
			}

			if len(res.Body) != 0 {
				if err := c.Send(res.Body); err != nil {
					return true, err
				}
			}

			_ = c.Locals(localsKeyIsFromCache, true)

			return true, nil
		}

		return false, nil
	}

	return func(c fiber.Ctx) error {
		// Don't execute middleware if Next returns true
		if cfg.Next != nil && cfg.Next(c) {
			return c.Next()
		}

		// Don't execute middleware if the idempotency key is empty