gofiber/fiber · error

fiber: keyauth error_uri must be absolute

Error message

fiber: keyauth error_uri must be absolute

What it means

When keyauth Config.ErrorURI is provided, the library parses it with url.Parse and requires an absolute URL (one with a scheme and host, e.g. https://...). A relative path or a value that fails to parse panics in configDefault(), because RFC 6750 requires error_uri to be an absolute URI.

Source

Thrown at middleware/keyauth/config.go:147

		cfg.Challenge = fmt.Sprintf("ApiKey realm=%q", cfg.Realm)
	}

	if cfg.Error != "" {
		switch cfg.Error {
		case ErrorInvalidRequest, ErrorInvalidToken, ErrorInsufficientScope:
		default:
			panic("fiber: keyauth unsupported error token")
		}
	}
	if cfg.ErrorDescription != "" && cfg.Error == "" {
		panic("fiber: keyauth error_description requires error")
	}
	if cfg.ErrorURI != "" {
		if cfg.Error == "" {
			panic("fiber: keyauth error_uri requires error")
		}
		if u, err := url.Parse(cfg.ErrorURI); err != nil || !u.IsAbs() {
			panic("fiber: keyauth error_uri must be absolute")
		}
	}
	if cfg.Error == ErrorInsufficientScope {
		if cfg.Scope == "" {
			panic("fiber: keyauth insufficient_scope requires scope")
		}
		for scope := range strings.SplitSeq(cfg.Scope, " ") {
			if scope == "" || !isScopeToken(scope) {
				panic("fiber: keyauth scope contains invalid token")
			}
		}
	} else if cfg.Scope != "" {
		panic("fiber: keyauth scope requires insufficient_scope error")
	}

	return cfg
}

View on GitHub (pinned to 9a4c7e57fe)

Solutions

1. Provide a full absolute URL including scheme, e.g. "https://example.com/docs/auth-errors".
2. Build the URL from a configured base so it stays absolute across environments.
3. Verify the value parses with net/url and u.IsAbs() returns true before passing it to keyauth.New().

Example fix

// before
app.Use(keyauth.New(keyauth.Config{
    Validator: validateKey,
    Error:     keyauth.ErrorInvalidToken,
    ErrorURI:  "/docs/auth-errors",
}))
// after
app.Use(keyauth.New(keyauth.Config{
    Validator: validateKey,
    Error:     keyauth.ErrorInvalidToken,
    ErrorURI:  "https://example.com/docs/auth-errors",
}))

if cfg.ErrorURI != "" {
    u, err := url.Parse(cfg.ErrorURI)
    if err != nil || !u.IsAbs() {
        log.Fatalf("keyauth: ErrorURI %q must be an absolute URL", cfg.ErrorURI)
    }
}

When it happens

Trigger: Setting Config.ErrorURI to a relative path like "/docs/errors", a path without scheme like "example.com/errors", or a malformed string that url.Parse rejects. This triggers the panic at middleware construction.

Common situations: Developer reuses an internal route path instead of a fully-qualified URL. Environment-specific base URLs omitted because the dev assumed a relative path is fine. Copying a path from a frontend router config.

Related errors

• fiber: keyauth unsupported error token
• fiber: keyauth error_description requires error
• fiber: keyauth error_uri requires error
• fiber: keyauth insufficient_scope requires scope
• fiber: keyauth scope contains invalid token

AI-assisted analysis of gofiber/fiber@9a4c7e57fe (2026-08-04). Data as JSON: /data/errors/3dd0367705034193.json. Report an issue: GitHub.