What causes "download failed: HTTP %d" in siyuan-note/siyuan?

404: verify owner/repo, branch name, and file path; prefer the tree/ URL form.

download failed: HTTP %d

Error message

download failed: HTTP %d

What it means

Thrown by fetchBytes when the HTTP response status code is 400 or above. The status number is formatted into the message. It surfaces server-side rejections (not found, forbidden, rate limit, server error) distinctly from transport errors.

Source

Thrown at kernel/util/skill.go:408

		data, contentType, ferr := fetchBytes(fallback.downloadURL)
		if ferr != nil {
			return nil, "", fmt.Errorf("download failed (tried main and master): %v", err)
		}
		return data, contentType, nil
	}
	return nil, "", err
}

// fetchBytes 执行带大小限制的 GET
func fetchBytes(rawURL string) (data []byte, contentType string, err error) {
	resp, err := httpclient.NewBrowserRequest().Get(rawURL)
	if err != nil {
		return nil, "", errors.New("download failed: " + err.Error())
	}
	defer resp.Body.Close()

	if resp.StatusCode >= 400 {
		return nil, "", fmt.Errorf("download failed: HTTP %d", resp.StatusCode)
	}

	contentType = resp.Header.Get("Content-Type")
	body, err := io.ReadAll(io.LimitReader(resp.Body, maxSkillDownloadBytes+1))
	if err != nil {
		return nil, "", errors.New("read body failed: " + err.Error())
	}
	if len(body) > maxSkillDownloadBytes {
		return nil, "", errors.New("skill source too large (limit 10MB)")
	}
	return body, contentType, nil
}

// installFromZip 解压 zip 并安装其中的 skill
func installFromZip(data []byte) (*InstallSkillResult, error) {
	tmpRoot := filepath.Join(TempDir, "ai", "skill-install", gulu.Rand.String(7))
	if err := os.MkdirAll(tmpRoot, 0755); err != nil {
		return nil, err

View on GitHub (pinned to 251596fc0d)

Solutions

404: verify owner/repo, branch name, and file path; prefer the tree/<branch> URL form.
403: reduce request frequency, wait out the rate-limit window, or authenticate via a token-bearing URL where supported.
5xx: retry after a short delay; check status.github.com.
For release assets, confirm the exact tag and asset filename from the releases page.

Defensive patterns

Strategy: try-catch

Try / catch

res, err := util.InstallSkill(src)
if err != nil {
    if strings.Contains(err.Error(), "HTTP 404") {
        return errors.New("skill source not found; check the owner/repo, branch, and path")
    }
    if strings.Contains(err.Error(), "HTTP 403") {
        return errors.New("access denied or rate-limited by GitHub; wait and retry, or use an authenticated URL")
    }
    return err
}

Prevention

Verify owner/repo and branch spellings before installing.
Cache successful downloads to reduce repeated hits that trigger rate limits.
For release assets, confirm the exact tag and filename from the releases page.

When it happens

Trigger: 404 for a non-existent repo/file/branch; 403 or 401 for private repos or rate limiting; 5xx for upstream outages; release asset URL returning 404 because the tag/asset name is wrong.

Common situations: Wrong owner/repo or branch (404); GitHub rate limit on unauthenticated codeload (403); private repo (404/401); a release asset renamed or removed; GitHub incident (5xx).

Related errors

AI-assisted analysis of siyuan-note/siyuan@251596fc0d (2026-08-12). Data as JSON: /api/errors/5fc586aa309a52e9. Report an issue: GitHub.