* <li>{@link #TEXT} - The text content field.</li>
 * <li>{@link #READING_PREFIX} - The prefix for reading fields.</li>
 * <li>{@link #SCORE} - The score field.</li>
 * <li>{@link #QUERY_FREQ} - The query frequency field.</li>
 * <li>{@link #DOC_FREQ} - The document frequency field.</li>
 * <li>{@link #USER_BOOST} - The user boost field.</li>
 * <li>{@link #KINDS} - The kinds field.</li>

    public Map<String, String[]> fields = new HashMap<>();

    /**
     * Map of advanced search conditions.
     */
    public Map<String, String[]> as = new HashMap<>();

    /**
     * The main search query string.
     */
    @Size(max = 1000)
    public String q;

    /**
     * The sort parameter for search results.
     */
    @Size(max = 1000)
    public String sort;

    /**

  val bootstrapClient = OkHttpClient.Builder().cache(appCache).build()

  val dns = DnsOverHttps.Builder().client(bootstrapClient)
    .url("https://dns.google/dns-query".toHttpUrl())
    .bootstrapDnsHosts(InetAddress.getByName("8.8.4.4"), InetAddress.getByName("8.8.8.8"))
    .build()

  val client = bootstrapClient.newBuilder().dns(dns).build()
```

В нём будет *операция пути*, которая получит тело запроса `Invoice`, и query-параметр `callback_url`, содержащий URL для обратного вызова.

Эта часть вполне обычна, большая часть кода вам уже знакома:

{* ../../docs_src/openapi_callbacks/tutorial001_py310.py hl[7:11,34:51] *}

/// tip | Совет

def write_log(message: str):
    with open("log.txt", mode="a") as log:
        log.write(message)


def get_query(background_tasks: BackgroundTasks, q: str | None = None):
    if q:
        message = f"found query: {q}\n"
        background_tasks.add_task(write_log, message)
    return q


@app.post("/send-notification/{email}")
async def send_notification(

def write_log(message: str):
    with open("log.txt", mode="a") as log:
        log.write(message)


def get_query(background_tasks: BackgroundTasks, q: Union[str, None] = None):
    if q:
        message = f"found query: {q}\n"
        background_tasks.add_task(write_log, message)
    return q


@app.post("/send-notification/{email}")
async def send_notification(

    @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";

## 定义 `Form` 参数

创建表单（`Form`）参数的方式与 `Body` 和 `Query` 一样：

{* ../../docs_src/request_forms/tutorial001.py hl[7] *}

例如，OAuth2 规范的 "密码流" 模式规定要通过表单字段发送 `username` 和 `password`。

<abbr title="specification">该规范</abbr>要求字段必须命名为 `username` 和 `password`，并通过表单字段发送，不能用 JSON。

使用 `Form` 可以声明与 `Body` （及 `Query`、`Path`、`Cookie`）相同的元数据和验证。

/// info | 说明

`Form` 是直接继承自 `Body` 的类。

///

  - Tutorial - User Guide:
    - tutorial/index.md
    - tutorial/first-steps.md
    - tutorial/path-params.md
    - tutorial/query-params.md
    - tutorial/body.md
    - tutorial/query-params-str-validations.md
    - tutorial/path-params-numeric-validations.md
    - tutorial/query-param-models.md
    - tutorial/body-multiple-params.md
    - tutorial/body-fields.md
    - tutorial/body-nested-models.md