siyuan-note/siyuan · error

path must start with /

Error message

path must start with /

What it means

Thrown by siyuan.client.fetch when the first argument (path) is a string but does not begin with '/'. fetch only accepts a server-relative path because it rewrites it to http://127.0.0.1:<port><path>; absolute or scheme-relative URLs are rejected to keep plugin requests on the local kernel.

Source

Thrown at kernel/plugin/api_client.go:64

	client := rt.NewObject()

	lo.Must0(client.Set("fetch", rt.ToValue(func(call goja.FunctionCall, rt *goja.Runtime) goja.Value {
		promise, resolve, reject := rt.NewPromise()

		var argErr error
		var path string
		method := "GET"
		headers := map[string]string{}
		var bodyString *string
		var bodyBytes *[]byte

		if goja.IsString(call.Argument(0)) {
			path = call.Argument(0).String()
		} else {
			argErr = fmt.Errorf("path required")
		}
		if argErr == nil && !strings.HasPrefix(path, "/") {
			argErr = fmt.Errorf("path must start with /")
		}
		if argErr == nil {
			if init := call.Argument(1); isJsValueNotNull(init) {
				if initObj := init.ToObject(rt); initObj != nil {
					if m := initObj.Get("method"); goja.IsString(m) {
						method = m.String()
					}

					if h := initObj.Get("headers"); isJsValueNotNull(h) {
						if exportErr := rt.ExportTo(h, &headers); exportErr != nil {
							argErr = fmt.Errorf("failed to export headers: %w", exportErr)
						}
					}

					if argErr == nil {
						if b := initObj.Get("body"); isJsValueNotNull(b) {
							if goja.IsString(b) {
								bodyString = new(b.String())

View on GitHub (pinned to 251596fc0d)

Solutions

1. Prefix the path with '/' so it is server-relative, e.g. '/api/query/similarBlocks'.
2. Normalize once: const p = path.startsWith('/') ? path : '/' + path.
3. Do not pass a full URL; fetch only targets the local kernel. Strip the origin/host before calling.

Example fix

// before
await siyuan.client.fetch('api/query/similarBlocks', { method: 'POST', body: '{}' });
// after
await siyuan.client.fetch('/api/query/similarBlocks', { method: 'POST', body: '{}' });

function safePath(p) {
  if (typeof p !== 'string') throw new TypeError('path must be a string');
  if (!p.startsWith('/')) throw new Error("path must start with /");
  return p;
}
await siyuan.client.fetch(safePath(path));

const isServerPath = (v) => typeof v === 'string' && v.startsWith('/');

When it happens

Trigger: Calling fetch('api/foo') (missing leading slash), fetch('http://host/api/foo') (absolute URL), or fetch('//host/path') (protocol-relative). Any string passed as arg 0 that lacks a '/' prefix fails the strings.HasPrefix check at api_client.go:63.

Common situations: Plugin author copies a URL from browser devtools (which may keep a relative form), builds the path from a variable that was trimmed, or mistakes siyuan.client.fetch for the browser fetch (which accepts full URLs).

Related errors

• custom emoji name must not be empty
• invalid path
• Untitled
• Cannot create a file starting with .
• Duplicated filename

AI-assisted analysis of siyuan-note/siyuan@251596fc0d (2026-08-12). Data as JSON: /api/errors/886561280f49dc3f. Report an issue: GitHub.