siyuan-note/siyuan · error

unsupported system proxy protocol [%s]

Error message

unsupported system proxy protocol [%s]

What it means

When SiYuan reads the system proxy settings it normalizes each proxy address to a URL and only accepts http, https, socks5 and socks5h schemes. If the address parses but carries any other scheme (e.g. socks4, ftp, pac), normalizeSystemNetworkProxyURL rejects it with this error and the system proxy import fails.

Source

Thrown at kernel/util/system_proxy.go:108

	if "" == ret.HTTPProxy && "" == ret.HTTPSProxy {
		return nil, fmt.Errorf("system proxy does not contain a supported HTTP, HTTPS or SOCKS proxy")
	}
	return ret, nil
}

func normalizeSystemNetworkProxyURL(address, defaultScheme string) (string, error) {
	address = strings.TrimSpace(address)
	if !strings.Contains(address, "://") {
		address = defaultScheme + "://" + address
	}
	proxyURL, err := url.Parse(address)
	if err != nil || "" == proxyURL.Host {
		return "", fmt.Errorf("invalid system proxy address")
	}
	switch strings.ToLower(proxyURL.Scheme) {
	case "http", "https", "socks5", "socks5h":
	default:
		return "", fmt.Errorf("unsupported system proxy protocol [%s]", proxyURL.Scheme)
	}
	return proxyURL.String(), nil
}

func parseSystemNetworkProxyBypass(proxyOverride string) string {
	entries := []string{}
	seen := map[string]bool{}
	add := func(entry string) {
		if "" != entry && !seen[entry] {
			entries = append(entries, entry)
			seen[entry] = true
		}
	}
	for _, field := range strings.Split(proxyOverride, ";") {
		field = strings.TrimSpace(field)
		if strings.EqualFold(field, "<local>") {
			add("localhost")
			add("127.0.0.1")

View on GitHub (pinned to 8641553a1f)

Solutions

1. Change the proxy entry to use a supported scheme: http://, https://, socks5:// or socks5h://
2. If the upstream proxy is SOCKS4, replace it with a SOCKS5-capable proxy or a converter
3. Remove the scheme entirely (e.g. '127.0.0.1:8080'); the default http scheme is then applied automatically

Example fix

// before
proxies["http"] = "socks4://127.0.0.1:1080"
// after
proxies["http"] = "socks5://127.0.0.1:1080"

u, err := url.Parse(strings.TrimSpace(proxyAddr))
if err != nil || u.Host == "" {
	return fmt.Errorf("invalid system proxy address")
}
switch strings.ToLower(u.Scheme) {
case "http", "https", "socks5", "socks5h", "": // empty gets default scheme
default:
	return fmt.Errorf("unsupported system proxy protocol [%s]", u.Scheme)
}

func isSupportedProxyScheme(addr string) bool {
	u, err := url.Parse(addr)
	if err != nil || u.Host == "" {
		return false
	}
	switch strings.ToLower(u.Scheme) {
	case "http", "https", "socks5", "socks5h":
		return true
	}
	return !strings.Contains(addr, "://") // scheme-less defaults to http
}

cfg, err := parseSystemNetworkProxy(proxyServer, proxyOverride)
if err != nil {
	logging.LogWarnf("skip system proxy: %s", err)
	cfg = nil // proceed without proxy
}

When it happens

Trigger: parseSystemNetworkProxy is given a ProxyServer string (Windows registry ProxyServer, env-style config) whose address contains a scheme not in the allow-list, e.g. 'socks4=127.0.0.1:1080', 'ftp=http://proxy:8080' or a URL literally starting with 'file://' — normalizeSystemNetworkProxyURL hits the default branch of the scheme switch.

Common situations: Users behind corporate proxies configured with SOCKS4, or Windows proxy entries that were pasted from tools emitting exotic schemes; also typos like 'httpx://host:port'.

Understand the failure class

Background: Invalid enum value errors: "Unknown type", "Invalid scope", "must be one of" — when a string is not on the library's allowed list — this error's family across 23 libraries.

Related errors

• parse [u] failed: %s
• proxy returned unexpected tunnel data
• URL must start with http:// or https://
• SOCKS5 proxy does not support context dialing
• proxy CONNECT returned %s

AI-assisted analysis of siyuan-note/siyuan@8641553a1f (2026-09-11). Data as JSON: /api/errors/b0814850485c48b1. Report an issue: GitHub.