Tencent/WeKnora · error

decode extract_result object: %w

Error message

decode extract_result object: %w

What it means

The extract_result field did not start with '[', so the library decodes it as a single extractResultItem object; that object decode failed (mineru_cloud_converter.go:321). This means the doubly-encoded JSON inside extract_result is neither a valid single item object nor (per 853) a valid array. Usually the payload is malformed or the schema diverged from extractResultItem.

Source

Thrown at internal/infrastructure/docparser/mineru_cloud_converter.go:321

		logger.Infof(context.Background(), "[MinerUCloud] Raw extract_result: %s", rawExtract)
	}

	// Pretty-print the structure to reveal all available fields
	var rawObj interface{}
	if err := json.Unmarshal(pollResp.Data.ExtractResult, &rawObj); err == nil {
		logResponseStructure("MinerUCloud", rawObj, "extract_result")
	}

	// The extract_result can be either a single object or an array
	var items []extractResultItem
	if pollResp.Data.ExtractResult[0] == '[' {
		if err := json.Unmarshal(pollResp.Data.ExtractResult, &items); err != nil {
			return nil, fmt.Errorf("decode extract_result array: %w", err)
		}
	} else {
		var single extractResultItem
		if err := json.Unmarshal(pollResp.Data.ExtractResult, &single); err != nil {
			return nil, fmt.Errorf("decode extract_result object: %w", err)
		}
		items = []extractResultItem{single}
	}

	return items, nil
}

// extractDoneResult extracts markdown and images from a completed batch item.
// Prefers inline markdown/content fields; falls back to downloading full_zip_url.
func (c *MinerUCloudReader) extractDoneResult(_ context.Context, item *extractResultItem) (string, []types.ImageRef, error) {
	text := firstNonEmpty(item.Markdown, item.Content, item.Text)
	if text != "" {
		logger.Infof(context.Background(), "[MinerUCloud] parsed (inline), length=%d", len(text))
		return text, nil, nil
	}

	if item.FullZipURL == "" {
		return "", nil, fmt.Errorf("MinerU Cloud state=done but no markdown/content or full_zip_url")

View on GitHub (pinned to 988cbb0330)

Solutions

1. Log the raw extract_result string to see the actual shape returned.
2. Update extractResultItem to match the current MinerU Cloud response schema.
3. Add a fallback decode into json.RawMessage / map[string]any to introspect unknown shapes instead of failing outright.
4. Verify you are using a compatible MinerU Cloud API version/endpoint.

Example fix

// before
var single extractResultItem
if err := json.Unmarshal(pollResp.Data.ExtractResult, &single); err != nil {
    return nil, fmt.Errorf("decode extract_result object: %w", err)
}
// after — log the payload for diagnosis
var single extractResultItem
if err := json.Unmarshal(pollResp.Data.ExtractResult, &single); err != nil {
    return nil, fmt.Errorf("decode extract_result object: %w (payload: %.300s)", err, string(pollResp.Data.ExtractResult))
}

var raw any
if err := json.Unmarshal(pollResp.Data.ExtractResult, &raw); err != nil {
    return fmt.Errorf("extract_result is not valid JSON: %w", err)
}
if _, ok := raw.(map[string]any); !ok {
    return errors.New("extract_result is not a JSON object")
}

func isExtractResultObject(raw json.RawMessage) bool {
    var obj map[string]json.RawMessage
    return json.Unmarshal(raw, &obj) == nil
}

items, err := pollBatchResult(ctx, batchID)
if err != nil {
    if strings.Contains(err.Error(), "decode extract_result object") {
        // introspect payload; report contract mismatch
        return fmt.Errorf("unexpected extract_result shape: %w", err)
    }
    return err
}

When it happens

Trigger: fetchBatchStatus receives extract_result that is neither '['-prefixed nor a JSON object matching extractResultItem — e.g. a quoted plain string, an object with renamed fields, or corrupted doubly-encoded JSON.

Common situations: MinerU Cloud returning a failure/status-only object without the expected fields plus changed types; API upgrades changing field names (e.g. full_zip_url moved); mocking/stub environments returning simplified payloads.

Related errors

• decode extract_result array: %w
• decode poll response: %w
• failed to decode API response: %w
• failed to set FAQ metadata: %w
• unmarshal page: %w

AI-assisted analysis of Tencent/WeKnora@988cbb0330 (2026-09-02). Data as JSON: /api/errors/bb7b1a9978d3d706. Report an issue: GitHub.