What causes "too many redirects" in chenhg5/cc-connect?

Use a direct, non-redirecting image URL (the final destination after following redirects manually).

too many redirects

Error message

too many redirects

What it means

The rich-card image fetcher limits redirect chains to 3 hops via http.Client's CheckRedirect. When a URL redirects more than twice, it returns this error to stop infinite/long redirect loops, which also serves as SSRF protection since each hop is re-validated. The http.Client then surfaces it wrapped in url.Error.

Source

Thrown at platform/feishu/feishu.go:6596

	}
	return u.Hostname()
}

func fetchRichCardRemoteImage(ctx context.Context, rawURL string) ([]byte, string, error) {
	u, err := url.Parse(rawURL)
	if err != nil || (u.Scheme != "http" && u.Scheme != "https") || u.Host == "" {
		return nil, "", errors.New("invalid remote image URL")
	}

	client := &http.Client{
		Timeout: richCardImageFinalWait,
		Transport: &http.Transport{
			DialContext:           dialPublicRichCardImageContext,
			ResponseHeaderTimeout: richCardImageFinalWait,
		},
		CheckRedirect: func(req *http.Request, via []*http.Request) error {
			if len(via) >= 3 {
				return errors.New("too many redirects")
			}
			if !isRemoteRichCardImageURL(req.URL.String()) {
				return errors.New("redirected to unsupported image URL")
			}
			return nil
		},
	}

	req, err := http.NewRequestWithContext(ctx, http.MethodGet, rawURL, nil)
	if err != nil {
		return nil, "", err
	}
	req.Header.Set("User-Agent", "cc-connect-feishu-rich-card-image-resolver/1.0")

	resp, err := client.Do(req)
	if err != nil {
		return nil, "", err
	}

View on GitHub (pinned to 4000b2338a)

Solutions

Use a direct, non-redirecting image URL (the final destination after following redirects manually).
Pre-resolve the redirect chain once and store the final URL.
Ask the content provider to fix the redirect loop; verify the URL with curl -IL to count hops.

Example fix

// before
card.ImageURL = "https://shortener.example.com/img/abc123"
// after
finalURL := resolveRedirects("https://shortener.example.com/img/abc123") // follow once at ingestion time
card.ImageURL = finalURL

Defensive patterns

Strategy: fallback

Validate before calling

client := &http.Client{CheckRedirect: func(req *http.Request, via []*http.Request) error {
    if len(via) >= 3 { return errors.New("too many redirects") }
    return nil
}}
// HEAD the URL first to count hops before card rendering

Try / catch

var urlErr *url.Error
if errors.As(err, &urlErr) && strings.Contains(urlErr.Err.Error(), "too many redirects") {
    // use a cached/proxied copy of the image instead
}

Prevention

Prefer direct CDN URLs over shorteners in generated card content.
Resolve shortener chains once at ingestion and store the final URL.
Cache successfully fetched images and reuse them instead of refetching redirecting URLs.

When it happens

Trigger: Fetching a rich card image whose server issues a >=3-deep redirect chain (platform/feishu/feishu.go:6596); also triggered when any redirect hop fails the isRemoteRichCardImageURL re-validation, though that yields the redirect-target error instead.

Common situations: Image CDN behind multiple chained redirects (auth -> geo -> CDN); redirect loops caused by misconfigured servers; shortener services that redirect several times; expired URLs redirecting to login pages repeatedly.

Related errors

AI-assisted analysis of chenhg5/cc-connect@4000b2338a (2026-09-06). Data as JSON: /api/errors/d8d9f9f263adfb8e. Report an issue: GitHub.