What causes "wecom-ws: send file: %w" in chenhg5/cc-connect?

Unwrap the error chain (%w) to find the underlying upload stage that failed

wecom-ws: send file: %w

Error message

wecom-ws: send file: %w

What it means

SendFile wraps any failure from uploadWSMedia (the init/chunk/finish WebSocket upload that yields a media_id) with this prefix. The wrapped error chain contains the real cause — upload chunk timeout, finish failure, or decode error from the same file.

Source

Thrown at platform/wecom/websocket_outbound_media.go:173

	}
}

// SendFile uploads and sends a file through the WeCom AI Bot WebSocket API.
func (p *WSPlatform) SendFile(ctx context.Context, rctx any, file core.FileAttachment) error {
	rc, ok := rctx.(wsReplyContext)
	if !ok {
		return fmt.Errorf("wecom-ws: SendFile: invalid reply context type %T", rctx)
	}
	if rc.chatID == "" {
		return fmt.Errorf("wecom-ws: chatID is empty, cannot send file")
	}
	if len(file.Data) == 0 {
		return fmt.Errorf("wecom-ws: file data is empty")
	}

	mediaID, err := p.uploadWSMedia(ctx, "file", wsFileFileName(file), file.Data)
	if err != nil {
		return fmt.Errorf("wecom-ws: send file: %w", err)
	}
	if err := p.sendWSMediaMessage(ctx, rc.chatID, "file", mediaID); err != nil {
		return fmt.Errorf("wecom-ws: send file: %w", err)
	}
	return nil
}

func wsFileFileName(file core.FileAttachment) string {
	name := filepath.Base(strings.TrimSpace(file.FileName))
	if name != "" && name != "." {
		return name
	}
	switch strings.ToLower(file.MimeType) {
	case "text/html":
		return "file.html"
	case "application/pdf":
		return "file.pdf"
	case "text/plain":

View on GitHub (pinned to 4000b2338a)

Solutions

Unwrap the error chain (%w) to find the underlying upload stage that failed
Retry SendFile once after verifying the WS connection; transient timeouts are common
Reduce file size or chunk size if timeouts recur
Check WeCom AI Bot quota/permissions for media uploads

Defensive patterns

Strategy: try-catch

Validate before calling

if len(file.Data) == 0 || file.Data == nil {
	return fmt.Errorf("no data to upload")
}

Try / catch

if err := p.SendFile(ctx, rc, file); err != nil {
	var netErr net.Error
	if errors.As(err, &netErr) && netErr.Timeout() {
		// reconnect WS and retry upload once
	}
	return fmt.Errorf("file delivery failed: %w", err)
}

Prevention

Always inspect errors.As/Unwrap — the real cause is one level down
Check WS health before large uploads
Retry once for transient timeouts; abort on repeated failures

When it happens

Trigger: SendFile → uploadWSMedia returns any error: chunk send timeout, finish timeout, finish decode failure, or empty media_id.

Common situations: WS connection dropped during a large upload; per-chunk ack timeout on slow networks; WeCom server rejecting the upload session due to size or permissions.

Understand the failure class

Background: "API request failed": what wrapped HTTP errors from external APIs mean and how to find the real cause — this error's family across 29 libraries.

Related errors

AI-assisted analysis of chenhg5/cc-connect@4000b2338a (2026-09-06). Data as JSON: /api/errors/6baa24db8e69f586. Report an issue: GitHub.