JuliusBrussee/caveman · error

provider %q upstream URL scheme %q is not allowed

Error message

provider %q upstream URL scheme %q is not allowed

What it means

parseBaseURL only accepts http and https upstream schemes; the configured URL for the named provider uses another scheme (e.g. file or ftp) and is rejected before any request is forwarded.

Source

Thrown at proxy/providers/openaicompat/openaicompat.go:345

	// a path cannot change route identity after another decoder or proxy hop.
	for _, escape := range []string{"%2f", "%5c", "%2e"} {
		if strings.Contains(strings.ToLower(path), escape) || strings.Contains(strings.ToLower(rawPath), escape) {
			return fmt.Errorf("ambiguous escaped path sequence %s", escape)
		}
	}
	return nil
}

func parseBaseURL(raw, provider string) (*url.URL, error) {
	if strings.TrimSpace(raw) == "" {
		return nil, fmt.Errorf("provider %q has no configured upstream URL", provider)
	}
	u, err := url.Parse(strings.TrimSpace(raw))
	if err != nil {
		return nil, err
	}
	if u.Scheme != "http" && u.Scheme != "https" {
		return nil, fmt.Errorf("provider %q upstream URL scheme %q is not allowed", provider, u.Scheme)
	}
	if !u.IsAbs() || u.Host == "" || u.Hostname() == "" {
		return nil, fmt.Errorf("provider %q upstream URL must be an absolute URL with a host", provider)
	}
	if u.User != nil {
		return nil, fmt.Errorf("provider %q upstream URL must not include userinfo", provider)
	}
	if u.Fragment != "" {
		return nil, fmt.Errorf("provider %q upstream URL must not include a fragment", provider)
	}
	if err := validatePathComponents(u.Path, u.RawPath); err != nil {
		return nil, fmt.Errorf("provider %q upstream URL path rejected: %w", provider, err)
	}
	return u, nil
}

View on GitHub (pinned to 5184b3d11a)

Solutions

1. Use an http:// or https:// upstream URL
2. Do not point compat upstreams at unix sockets or file URLs

When it happens

Trigger: Thrown at proxy/providers/openaicompat/openaicompat.go:302 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of JuliusBrussee/caveman@5184b3d11a (2026-08-18). Data as JSON: /api/errors/5abcb9739c468e7f. Report an issue: GitHub.