Function New

middleware/cors/cors.go:27–206

New creates a new middleware handler

(config ...Config)

// New creates a new middleware handler
func New(config ...Config) fiber.Handler {
	// Set default config
	cfg := ConfigDefault

	// Override config if provided
	if len(config) > 0 {
		cfg = config[0]

		// Set default values
		if len(cfg.AllowMethods) == 0 {
			cfg.AllowMethods = ConfigDefault.AllowMethods
		}
	}

	redactValues := !cfg.DisableValueRedaction

	maskValue := func(value string) string {
		if redactValues {
			return redactedValue
		}
		return value
	}

	// Warning logs if both AllowOrigins and AllowOriginsFunc are set
	if len(cfg.AllowOrigins) > 0 && cfg.AllowOriginsFunc != nil {
		log.Warn("[CORS] Both 'AllowOrigins' and 'AllowOriginsFunc' have been defined.")
	}

	// allowOrigins is a set of strings that contains the allowed origins
	// defined in the 'AllowOrigins' configuration.
	allowOrigins := make(map[string]struct{}, len(cfg.AllowOrigins))
	allowSubOrigins := []subdomain{}

	// Validate and normalize static AllowOrigins
	allowAllOrigins := len(cfg.AllowOrigins) == 0 && cfg.AllowOriginsFunc == nil
	for _, origin := range cfg.AllowOrigins {
		if origin == "*" {
			allowAllOrigins = true
			break
		}

		trimmedOrigin := utils.TrimSpace(origin)
		if before, after, found := strings.Cut(trimmedOrigin, "://*."); found {
			withoutWildcard := before + "://" + after
			isValid, normalizedOrigin := normalizeOrigin(withoutWildcard)
			if !isValid {
				panic("[CORS] Invalid origin format in configuration: " + maskValue(trimmedOrigin))
			}
			scheme, host, ok := strings.Cut(normalizedOrigin, "://")
			if !ok {
				panic("[CORS] Invalid origin format after normalization:" + maskValue(trimmedOrigin))
			}
			sd := subdomain{prefix: scheme + "://", suffix: host}
			allowSubOrigins = append(allowSubOrigins, sd)
		} else {
			isValid, normalizedOrigin := normalizeOrigin(trimmedOrigin)
			if !isValid {
				panic("[CORS] Invalid origin format in configuration: " + maskValue(trimmedOrigin))