## Use case { #use-case }

For example, imagine that you want to return an HTTP status code of "OK" `200` by default.

But if the data didn't exist, you want to create it, and return an HTTP status code of "CREATED" `201`.

But you still want to be able to filter and convert the data you return with a `response_model`.

For those cases, you can use a `Response` parameter.

## Use a `Response` parameter { #use-a-response-parameter }

// migration fails upon any error.
func formatErasureMigrateV1ToV2(data []byte, version string) ([]byte, error) {
	if version != formatErasureVersionV1 {
		return nil, fmt.Errorf(`format version expected %s, found %s`, formatErasureVersionV1, version)
	}

	formatV1 := &formatErasureV1{}
	if err := json.Unmarshal(data, formatV1); err != nil {
		return nil, err
	}

	formatV2 := &formatErasureV2{}

	var gnuLongName, gnuLongLink string

	// Externally, Next iterates through the tar archive as if it is a series of
	// files. Internally, the tar format often uses fake "files" to add meta
	// data that describes the next file. These meta data "files" should not
	// normally be visible to the outside. As such, this loop iterates through
	// one or more "header files" until it finds a "normal file".
	format := FormatUSTAR | FormatPAX | FormatGNU

	data, _, err := readConfigWithMetadata(ctx, store, rebalMetaName, opts)
	if err != nil {
		return err
	}

	if len(data) == 0 {
		return nil
	}
	if len(data) <= 4 {
		return fmt.Errorf("rebalanceMeta: no data")
	}

	// Read header
	switch binary.LittleEndian.Uint16(data[0:2]) {
	case rebalMetaFmt:
	default:

        assertEquals(2, result); // Based on mock data
    }

    public void test_getMatchedLabelValueSet_multipleMatches() {
        // Load some test data first
        labelTypeHelper.load();

        Set<String> result = labelTypeHelper.getMatchedLabelValueSet("/test/path");
        assertNotNull(result);
        // Result depends on test data configuration
    }

    // Helper method to create test data

        assertTrue(response.hasMoreElements());
    }

    @Test
    @DisplayName("Test data handling with various sizes")
    void testDataHandlingWithVariousSizes() {
        // Test with small data count
        response.setDataCount(10);
        assertEquals(10, response.getDataCount());

        // Test with large data count
        response.setDataCount(65535);
        assertEquals(65535, response.getDataCount());

data/folder/file.html テスト data/file.txt テキスト...

/**
 * Container for SMB server negotiation data.
 * This class holds the server capabilities, configuration, and security
 * parameters received during SMB protocol negotiation.
 *
 * Stores server-specific data obtained during SMB1 protocol negotiation.
 */
public class ServerData {

    /**
     * Default constructor for ServerData.
     * Creates an empty server data container to be populated during SMB negotiation.
     */

# Den Request direkt verwenden

Bisher haben Sie die Teile des Requests, die Sie benötigen, mithilfe von deren Typen deklariert.

Daten nehmend von:

* Dem Pfad als Parameter.
* Headern.
* Cookies.
* usw.

Und indem Sie das tun, validiert **FastAPI** diese Daten, konvertiert sie und generiert automatisch Dokumentation für Ihre API.

Es gibt jedoch Situationen, in denen Sie möglicherweise direkt auf das `Request`-Objekt zugreifen müssen.

{* ../../docs_src/request_form_models/tutorial001_an_py39.py hl[9:11,15] *}

**FastAPI** will **extract** the data for **each field** from the **form data** in the request and give you the Pydantic model you defined.

## Check the Docs { #check-the-docs }

You can verify it in the docs UI at `/docs`:

<div class="screenshot">