chenhg5/cc-connect · warning

remote image exceeds %d bytes

Error message

remote image exceeds %d bytes

What it means

After streaming the body through io.LimitReader(richCardImageMaxBytes+1), the actual byte count exceeded richCardImageMaxBytes. This catches servers that send no/wrong Content-Length (chunked encoding) where the 1245 check cannot fire.

Source

Thrown at platform/feishu/feishu.go:6633

	defer func() {
		if err := resp.Body.Close(); err != nil {
			slog.Debug("feishu: close rich card image response body", "error", err)
		}
	}()

	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
		return nil, "", fmt.Errorf("remote image HTTP status %d", resp.StatusCode)
	}
	if resp.ContentLength > richCardImageMaxBytes {
		return nil, "", fmt.Errorf("remote image too large: %d bytes", resp.ContentLength)
	}

	data, err := io.ReadAll(io.LimitReader(resp.Body, richCardImageMaxBytes+1))
	if err != nil {
		return nil, "", err
	}
	if len(data) > richCardImageMaxBytes {
		return nil, "", fmt.Errorf("remote image exceeds %d bytes", richCardImageMaxBytes)
	}
	mimeType := http.DetectContentType(data)
	if !isSupportedRichCardImageMIME(mimeType) {
		return nil, "", fmt.Errorf("unsupported remote image MIME %q", mimeType)
	}
	return data, mimeType, nil
}

func dialPublicRichCardImageContext(ctx context.Context, network, address string) (net.Conn, error) {
	host, port, err := net.SplitHostPort(address)
	if err != nil {
		return nil, err
	}

	var ips []net.IP
	if parsed := net.ParseIP(host); parsed != nil {
		ips = []net.IP{parsed}
	} else {

View on GitHub (pinned to 4000b2338a)

Solutions

1. Reduce image size server-side or switch to a thumbnail URL
2. Raise richCardImageMaxBytes if appropriate for the deployment
3. Point the card to a static file host that sets accurate Content-Length
4. Proxy and re-encode the image through a resizing service

// after reading: if len(data) > limit { abort } — pre-check via HEAD request Content-Length when available

When it happens

Trigger: Downloading a card image where the server omits Content-Length (chunked transfer) or lies about it, and the body turns out larger than the limit.

Common situations: Chunked responses from CDNs; streaming endpoints; servers with incorrect Content-Length headers.

Understand the failure class

Background: "File too large" / "file size exceeds limit" errors: why libraries cap file sizes and how to fix them — this error's family across 46 libraries.

Related errors

• remote image too large: %d bytes
• too many redirects
• remote image HTTP status %d
• invalid remote image URL
• init failed: %w

AI-assisted analysis of chenhg5/cc-connect@4000b2338a (2026-09-06). Data as JSON: /api/errors/d1f29995b5d793e3. Report an issue: GitHub.