import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.base.Function;
import com.google.common.base.Optional;
import com.google.common.base.Predicate;
import com.google.common.base.Predicates;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import com.google.errorprone.annotations.InlineMe;

 * Parses a given XML file, applies a set of changes, and writes those changes back to the original file.
 *
 * @param path Path to existing XML file
 * @param action Action to perform on parsed XML document
 * @param preface optional front matter to add after the XML declaration
 * but before the XML document, e.g. a doctype or comment
 */
void modifyXml(Object path, Action<? super Node> action, String preface = null) {
  Node xml = parseXml(path)

                    Artifact artifact = node.getArtifact();

                    try {
                        if (node.filterTrail(filter)) {
                            // If it was optional and not a direct dependency,
                            // we don't add it or its children, just allow the update of the version and artifactScope
                            if (node.isChildOfRootNode() || !artifact.isOptional()) {

    * чрезвычайно простые тесты на основе HTTPX и `pytest`
    * **CORS**
    * **сессии с использованием cookie**
    * ...и многое другое.

### Разверните приложение (опционально) { #deploy-your-app-optional }

При желании вы можете развернуть своё приложение FastAPI в [FastAPI Cloud](https://fastapicloud.com), присоединяйтесь к списку ожидания, если ещё не сделали этого. 🚀

### Kompakt { #short }

Es gibt für alles sensible **Defaultwerte**, mit optionaler Konfiguration überall. Alle Parameter können feinjustiert werden, damit sie tun, was Sie benötigen, und die API definieren, die Sie brauchen.

Aber standardmäßig **„funktioniert einfach alles“**.

* 许多额外特性（归功于 Starlette），例如：
    * **WebSockets**
    * 基于 HTTPX 和 `pytest` 的极其简单的测试
    * **CORS**
    * **Cookie Sessions**
    * ……以及更多。

### 部署你的应用（可选） { #deploy-your-app-optional }

你可以选择把 FastAPI 应用部署到 [FastAPI Cloud](https://fastapicloud.com)，如果还没有的话去加入候补名单吧。🚀

如果你已经有 **FastAPI Cloud** 账号（我们从候补名单邀请了你 😉），你可以用一个命令部署你的应用。

<div class="termy">

```console
$ fastapi deploy

import org.codelibs.fess.Constants;
import org.codelibs.fess.dict.DictionaryException;
import org.codelibs.fess.dict.DictionaryFile;
import org.codelibs.fess.util.ComponentUtil;
import org.dbflute.optional.OptionalEntity;

/**
 * Character mapping file handler for managing character mapping dictionaries.
 * This class provides functionality to load, parse, and manage character mapping

 * accuracy, use {@code System.nanoTime()} directly instead.
 *
 * <p>Basic usage:
 *
 * {@snippet :
 * Stopwatch stopwatch = Stopwatch.createStarted();
 * doSomething();
 * stopwatch.stop(); // optional
 *
 * Duration duration = stopwatch.elapsed();
 *
 * log.info("time: " + stopwatch); // formatted string like "12.3 ms"
 * }
 *

## An app with callbacks { #an-app-with-callbacks }

Let's see all this with an example.

Imagine you develop an app that allows creating invoices.

These invoices will have an `id`, `title` (optional), `customer`, and `total`.

The user of your API (an external developer) will create an invoice in your API with a POST request.

Then your API will (let's imagine):

{* ../../docs_src/body/tutorial001_py310.py hl[5:9] *}

就和宣告查詢參數時一樣，當模型屬性有預設值時，它就不是必填；否則就是必填。使用 `None` 可使其成為選填。

例如，上述模型對應的 JSON「`object`」（或 Python `dict`）如下：

```JSON
{
    "name": "Foo",
    "description": "An optional description",
    "price": 45.2,
    "tax": 3.5
}
```

...由於 `description` 與 `tax` 是選填（預設為 `None`），以下這個 JSON「`object`」也有效：

```JSON
{
    "name": "Foo",
    "price": 45.2
}
```