What causes "invalid proxy_url: scheme and host are required" in Tencent/WeKnora?

Add the scheme: change "localhost:8080" to "http://localhost:8080"

invalid proxy_url: scheme and host are required

Error message

invalid proxy_url: scheme and host are required

What it means

The proxy_url parsed successfully but lacks a scheme or a host, so it cannot be used as an HTTP proxy URL. This is a validation error distinct from parse failures; the URL syntax was fine but semantically incomplete.

Source

Thrown at internal/infrastructure/web_search/proxy.go:43

func NewSearchHTTPClient(timeout time.Duration, proxyURL string) (*http.Client, error) {
	proxyURL = strings.TrimSpace(proxyURL)
	def, ok := http.DefaultTransport.(*http.Transport)
	if !ok {
		return nil, fmt.Errorf("default HTTP transport is not *http.Transport")
	}
	t := def.Clone()
	t.DialContext = utils.SSRFSafeDialContext

	if proxyURL != "" {
		if err := ValidateProxyURL(proxyURL); err != nil {
			return nil, err
		}
		u, err := url.Parse(proxyURL)
		if err != nil {
			return nil, fmt.Errorf("invalid proxy_url: %w", err)
		}
		if u.Scheme == "" || u.Host == "" {
			return nil, fmt.Errorf("invalid proxy_url: scheme and host are required")
		}
		t.Proxy = http.ProxyURL(u)
	} else {
		t.Proxy = http.ProxyFromEnvironment
	}

	cfg := utils.DefaultSSRFSafeHTTPClientConfig()
	cfg.Timeout = timeout
	return utils.NewSSRFSafeHTTPClientWithTransport(cfg, t), nil
}

View on GitHub (pinned to 988cbb0330)

Solutions

Add the scheme: change "localhost:8080" to "http://localhost:8080"
Ensure the host is present, not just a scheme
Run ValidateProxyURL/url.Parse checks on config at startup, before provider creation
For SOCKS, use socks5:// explicitly

Example fix

// before
proxyURL := "10.0.0.5:3128"
// after
proxyURL := "http://10.0.0.5:3128"

Defensive patterns

Strategy: validation

Validate before calling

func hasSchemeAndHost(raw string) bool {
    u, err := url.Parse(strings.TrimSpace(raw))
    return err == nil && u.Scheme != "" && u.Host != ""
}
// usage: if proxyURL != "" && !hasSchemeAndHost(proxyURL) { ... reject ... }

Try / catch

client, err := web_search.NewSearchHTTPClient(timeout, proxyURL)
if err != nil {
    if strings.Contains(err.Error(), "scheme and host are required") {
        return fmt.Errorf("proxy_url %q needs scheme and host, e.g. http://proxy:8080", proxyURL)
    }
    return err
}

Prevention

Always include the scheme (http://, https://, socks5://) in proxy config
Add a UI/config-level regex check like ^[a-z][a-z0-9+.-]*://
Normalize config values with strings.TrimSpace before use
Document the expected format next to the proxy_url field

When it happens

Trigger: NewSearchHTTPClient called with values like "localhost:8080" (no scheme; url.Parse treats it as path-only), "/path/to/sock", or "" is allowed but "http://" (empty host) triggers this.

Common situations: Config values like "proxy.company.com:3128" without http://, YAML interpolation dropping the scheme, users entering only a hostname from proxy docs.

Related errors

AI-assisted analysis of Tencent/WeKnora@988cbb0330 (2026-09-02). Data as JSON: /api/errors/08c6361f126b63e8. Report an issue: GitHub.