private const val TYPE_PTR = 0x000c
  private val ASCII = Charsets.US_ASCII

  fun encodeQuery(
    host: String,
    type: Int,
  ): ByteString =
    Buffer()
      .apply {
        writeShort(0) // query id
        writeShort(256) // flags with recursion
        writeShort(1) // question count
        writeShort(0) // answerCount
        writeShort(0) // authorityResourceCount
        writeShort(0) // additional

Diese Parameter werden von **FastAPI** verwendet, um die Abhängigkeit „aufzulösen“.

In beiden Fällen wird sie haben:

* Einen optionalen `q`-Query-Parameter, der ein `str` ist.
* Einen `skip`-Query-Parameter, der ein `int` ist, mit einem Defaultwert `0`.
* Einen `limit`-Query-Parameter, der ein `int` ist, mit einem Defaultwert `100`.

In beiden Fällen werden die Daten konvertiert, validiert, im OpenAPI-Schema dokumentiert, usw.

		t.Errorf("no error should happen when query with embedded struct, but got %v", err)
	} else if egNews.BasePost.Title != "engadget_news" {
		t.Errorf("embedded struct's value should be scanned correctly")
	}

	var egPosts []EngadgetPost
	if err := DB.Order("author_name asc").Find(&egPosts).Error; err != nil {
		t.Fatalf("no error should happen when query with embedded struct, but got %v", err)
	}

{* ../../docs_src/schema_extra_example/tutorial002_py310.py hl[2,8:11] *}

## `examples` no JSON Schema - OpenAPI { #examples-in-json-schema-openapi }

Ao usar qualquer um de:

* `Path()`
* `Query()`
* `Header()`
* `Cookie()`
* `Body()`
* `Form()`
* `File()`

você também pode declarar um grupo de `examples` com informações adicionais que serão adicionadas aos seus **JSON Schemas** dentro do **OpenAPI**.

{* ../../docs_src/schema_extra_example/tutorial002_py310.py hl[2,8:11] *}

## `examples` en JSON Schema - OpenAPI { #examples-in-json-schema-openapi }

Cuando usas cualquiera de:

* `Path()`
* `Query()`
* `Header()`
* `Cookie()`
* `Body()`
* `Form()`
* `File()`

también puedes declarar un grupo de `examples` con información adicional que se añadirá a sus **JSON Schemas** dentro de **OpenAPI**.

There you can set:

* The "Item ID", used in the path.
* The "Token" used as a query parameter.

/// tip

Notice that the query `token` will be handled by a dependency.

///

With that you can connect the WebSocket and then send and receive messages:

<img src="/img/tutorial/websockets/image05.png">

          assertEquals(
              ImmutableList.copyOf(asMap.entrySet()).reverse(),
              ImmutableList.copyOf(descendingMap.entrySet()));

          for (Range<Integer> query : RANGES) {
            assertEquals(expectedAsMap.get(query), asMap.get(query));
          }
        }
      }
    }
  }


  public void testSubRangeMap() {
    for (Range<Integer> range1 : RANGES) {

    @Override
    public String toString() {
        String opCodeString, resultCodeString, questionTypeString, recordTypeString;

        opCodeString = switch (this.opCode) {
        case QUERY -> "QUERY";
        case WACK -> "WACK";
        default -> Integer.toString(this.opCode);
        };
        resultCodeString = switch (this.resultCode) {
        case FMT_ERR -> "FMT_ERR";

        final String questionClassString;
        String recordTypeString;
        final String recordClassString;

        opCodeString = switch (opCode) {
        case QUERY -> "QUERY";
        case WACK -> "WACK";
        default -> Integer.toString(opCode);
        };
        resultCodeString = switch (resultCode) {
        case FMT_ERR -> "FMT_ERR";
        case SRV_ERR -> "SRV_ERR";

这些额外的信息将按原样添加到输出的JSON模式中。

## `Field` 的附加参数

在 `Field`, `Path`, `Query`, `Body` 和其他你之后将会看到的工厂函数，你可以为JSON 模式声明额外信息，你也可以通过给工厂函数传递其他的任意参数来给JSON 模式声明额外信息，比如增加 `example`:

{* ../../docs_src/schema_extra_example/tutorial002_py310.py hl[2,8:11] *}

/// warning

请记住，传递的那些额外参数不会添加任何验证，只会添加注释，用于文档的目的。

///

## `Body` 额外参数

你可以通过传递额外信息给 `Field` 同样的方式操作`Path`, `Query`, `Body`等。

比如，你可以将请求体的一个 `example` 传递给 `Body`: