chenhg5/cc-connect · error

%s: build video message: %w

Error message

%s: build video message: %w

What it means

Failed to serialize the larkim.MessageMedia struct (containing the uploaded file_key) into the JSON message content string via mediaMsg.String(). This is a local JSON-marshalling failure, not an API failure.

Source

Thrown at platform/feishu/feishu.go:5587

			if !uploadResp.Success() {
				return fmt.Errorf("%s: upload video code=%d msg=%s", p.tag(), uploadResp.Code, uploadResp.Msg)
			}
			return nil
		})
	}); err != nil {
		return err
	}
	if uploadResp.Data == nil || uploadResp.Data.FileKey == nil {
		return fmt.Errorf("%s: upload video: no file_key returned", p.tag())
	}
	fileKey := *uploadResp.Data.FileKey

	slog.Debug(p.tag()+": video uploaded", "file_key", fileKey, "format", format, "size", len(video))

	mediaMsg := larkim.MessageMedia{FileKey: fileKey}
	mediaContent, err := mediaMsg.String()
	if err != nil {
		return fmt.Errorf("%s: build video message: %w", p.tag(), err)
	}

	return p.sendMediaMessage(ctx, rc, larkim.MsgTypeMedia, mediaContent)
}

type postElement struct {
	Tag      string `json:"tag"`
	Text     string `json:"text,omitempty"`
	Language string `json:"language,omitempty"`
	ImageKey string `json:"image_key,omitempty"`
	Href     string `json:"href,omitempty"`
	UserId   string `json:"user_id,omitempty"`
	UserName string `json:"user_name,omitempty"`
}

type postLang struct {
	Title   string          `json:"title"`
	Content [][]postElement `json:"content"`

View on GitHub (pinned to 4000b2338a)

Solutions

1. Upgrade/reinstall the Feishu SDK — a stock MessageMedia with a valid fileKey always marshals
2. Verify fileKey contains only the plain key string (no control characters injected)
3. Check vendor directory integrity (go mod verify)
4. If it persists, replace mediaMsg.String() with explicit json.Marshal of a map for debugging

content, err := mediaMsg.String()
if err != nil {
    slog.Error("media marshal failed", "err", err)
    return err
}

When it happens

Trigger: mediaMsg.String() returns an error, which for larkim.MessageContent implementations is practically only a json.Marshal failure — essentially never with a plain FileKey string field.

Common situations: Extremely rare in practice; could indicate a corrupted SDK install or a custom MessageMedia build with unmarshalable fields.

Understand the failure class

Background: json.Marshal / "failed to marshal" errors in Go: why "unsupported type" happens and how to fix it — this error's family across 22 libraries.

Related errors

• marshal Agy permission hook: %w
• marshal Agy hooks overlay: %w
• marshal stdin: %w
• codex app-server encode: %w
• decode response: %w

AI-assisted analysis of chenhg5/cc-connect@4000b2338a (2026-09-06). Data as JSON: /api/errors/450cac6c6b2bb9cc. Report an issue: GitHub.