chenhg5/cc-connect · error

webex: postFile status %d

Error message

webex: postFile status %d

What it means

The multipart upload POST to /messages (files form field) finished but the status was not 200 or 201. This is the file/attachment counterpart of postMessage's status guard: Webex rejected the upload, e.g. oversized file (413), unsupported media type, invalid roomId, or an auth failure — transport-level failures were already handled inside doWithRetry.

Source

Thrown at platform/webex/client.go:246

		name = "attachment"
	}
	part, err := w.CreateFormFile("files", name)
	if err != nil {
		return err
	}
	if _, err := part.Write(f.Data); err != nil {
		return err
	}
	if err := w.Close(); err != nil {
		return err
	}
	resp, err := c.doWithRetry(ctx, http.MethodPost, c.base()+"/messages", buf.Bytes(), w.FormDataContentType(), "webex: postFile")
	if err != nil {
		return err
	}
	defer func() { _ = resp.Body.Close() }()
	if resp.StatusCode != http.StatusOK && resp.StatusCode != http.StatusCreated {
		return fmt.Errorf("webex: postFile status %d", resp.StatusCode)
	}
	return nil
}

View on GitHub (pinned to 4000b2338a)

Solutions

1. Check the file size — keep under Webex's ~100MB limit, and compress if needed
2. Verify the MIME type is supported by Webex messaging (no arbitrary executables)
3. Confirm the bot is a member of the target room (404 case)
4. Retry with backoff on 429/5xx

Example fix

// before
err := client.PostFile(ctx, roomID, largeFile)
// after
if len(largeFile.Data) > 100*1024*1024 {
    return fmt.Errorf("file too large for webex")
}
err := client.PostFile(ctx, roomID, largeFile)

if len(f.Data) > 100*1024*1024 { return errors.New("file exceeds webex 100MB limit") }

err := client.PostFile(ctx, roomID, f)
if err != nil {
    if strings.Contains(err.Error(), "status 400") { return fmt.Errorf("unsupported file: %w", err) }
    return retryWithBackoff(err)
}

When it happens

Trigger: Multipart upload rejected: 400 (unsupported file type or size >100MB), 401 (token), 404 (bot not in room), 429 (rate limit), 5xx during upload.

Common situations: Uploading oversized files; Webex-restricted MIME types (e.g. executable formats); slow uploads hitting gateway timeouts; bot removed from target room.

Understand the failure class

Background: "API error: {status}" and "HTTP 401/403/404/429/5xx" errors: non-2xx HTTP responses explained — this error's family across 27 libraries.

Related errors

• dingtalk: upload image: %w
• create form file: %w
• write media data: %w
• close multipart writer: %w
• create upload request: %w

AI-assisted analysis of chenhg5/cc-connect@4000b2338a (2026-09-06). Data as JSON: /api/errors/ce20d1209a8f7875. Report an issue: GitHub.