FastAPI wird nun:

* Die Daten **validieren** und sicherstellen, dass sie nicht länger als 50 Zeichen sind
* Dem Client einen **verständlichen Fehler** anzeigen, wenn die Daten ungültig sind
* Den Parameter in der OpenAPI-Schema-*Pfadoperation* **dokumentieren** (sodass er in der **automatischen Dokumentation** angezeigt wird)

		return
	}

	dnList := r.Form["userDNs"]
	isAll := r.Form.Get("all") == "true"
	selfOnly := !isAll && len(dnList) == 0

	if isAll && len(dnList) > 0 {
		// This should be checked on client side, so return generic error
		writeErrorResponseJSON(ctx, w, errorCodes.ToAPIErr(ErrInvalidRequest), r.URL)
		return
	}

	// Empty DN list and not self, list access keys for all users
	if isAll {

Và có hàng tá các bản thay thế, tất cả đều dựa trên OpenAPI. Bạn có thể dễ dàng thêm bất kì bản thay thế bào cho ứng dụng của bạn được xây dựng với **FastAPI**.

Bạn cũng có thể sử dụng nó để sinh code tự động, với các client giao viết qua API của bạn. Ví dụ, frontend, mobile hoặc các ứng dụng IoT.

## Tóm lại, từng bước một

### Bước 1: import `FastAPI`

{* ../../docs_src/first_steps/tutorial001.py hl[1] *}

// alternatively the zero value of a Reader may be used after calling [Reset]
// on it.
type Reader struct {
	buf          []byte
	rd           io.Reader // reader provided by the client
	r, w         int       // buf read and write positions
	err          error
	lastByte     int // last byte read for UnreadByte; -1 means invalid
	lastRuneSize int // size of last rune read for UnreadRune; -1 means invalid
}

    }

    /**
     * Represents the status of an API response.
     */
    public enum Status {
        /** Successful response status. */
        OK(0),
        /** Bad request status indicating client error. */
        BAD_REQUEST(1),
        /** System error status indicating server error. */
        SYSTEM_ERROR(2),
        /** Unauthorized status indicating authentication failure. */
        UNAUTHORIZED(3),

   * Error}, or else as a last resort, wraps it in a {@code RuntimeException} and then propagates.
   *
   * <p>This method always throws an exception. The {@code RuntimeException} return type allows
   * client code to signal to the compiler that statements after the call are unreachable. Example
   * usage:
   *
   * <pre>
   * T doSomething() {
   *   try {
   *     return someMethodThatCouldThrowAnything();

	defer setObjectLayer(z)

	r := rand.New(rand.NewSource(time.Now().UnixNano()))
	attempt := 1
	for {
		var err error
		bootstrapTrace(fmt.Sprintf("poolMeta.Init: loading pool metadata, attempt: %d", attempt), func() {
			err = z.Init(ctx) // Initializes all pools.
		})
		if err != nil {
			if !configRetriableErrors(err) {
				logger.Fatal(err, "Unable to initialize backend")
			}

		HTTPStatusCode: http.StatusBadRequest,
	},
	ErrMissingSSECustomerKeyMD5: {
		Code:           "InvalidArgument",
		Description:    "Requests specifying Server Side Encryption with Customer provided keys must provide the client calculated MD5 of the secret key.",
		HTTPStatusCode: http.StatusBadRequest,
	},
	ErrSSECustomerKeyMD5Mismatch: {
		Code:           "InvalidArgument",

    assertEquals("[yam, bam, jam, ham]", Iterables.toString(list));
  }

  public void testLimit() {
    Iterable<String> iterable = newArrayList("foo", "bar", "baz");
    Iterable<String> limited = Iterables.limit(iterable, 2);

    List<String> expected = ImmutableList.of("foo", "bar");
    List<String> actual = newArrayList(limited);
    assertEquals(expected, actual);
    assertCanIterateAgain(limited);

    assertEquals("[yam, bam, jam, ham]", Iterables.toString(list));
  }

  public void testLimit() {
    Iterable<String> iterable = newArrayList("foo", "bar", "baz");
    Iterable<String> limited = Iterables.limit(iterable, 2);

    List<String> expected = ImmutableList.of("foo", "bar");
    List<String> actual = newArrayList(limited);
    assertEquals(expected, actual);
    assertCanIterateAgain(limited);