## 範例 { #example }

### 建立 { #create-it }

建立檔案 `main.py`，內容如下：

```Python
from fastapi import FastAPI

app = FastAPI()


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: str | None = None):
    return {"item_id": item_id, "q": q}
```

<details markdown="1">

          properties-content: |
            JAVA_HOME=$HOME/.java/$ES_BUILD_JAVA
            RUNTIME_JAVA_HOME=$HOME/.java/$ES_RUNTIME_JAVA
            JAVA15_HOME=$HOME/.java/openjdk15
      - shell: |
          #!/usr/local/bin/runbld --redirect-stderr

          # Fetch beats artifacts
          export ES_VERSION=$(grep 'elasticsearch' build-tools-internal/version.properties | awk '{print $3}')

```Dockerfile
# ✅ 請這樣做
CMD ["fastapi", "run", "app/main.py", "--port", "80"]
```

⛔️ Shell 形式：

```Dockerfile
# ⛔️ 請不要這樣做
CMD fastapi run app/main.py --port 80
```

務必總是使用 exec 形式，以確保 FastAPI 能夠優雅地關閉，並觸發 [lifespan events](../advanced/events.md)。

你可以在 [Docker 關於 shell 與 exec 形式的文件](https://docs.docker.com/reference/dockerfile/#shell-and-exec-form) 閱讀更多。

{* ../../docs_src/custom_response/tutorial009c_py310.py hl[9:14,17] *}

これまでは次のように返していたものが:

```json
{"message": "Hello World"}
```

...このレスポンスでは次のように返されます:

```json
{
  "message": "Hello World"
}
```

もちろん、JSONの整形以外にも、これを活用するもっと良い方法が見つかるはずです。 😉

### `orjson` か レスポンスモデルか { #orjson-or-response-model }

# - MSVC 14.39
# - LLVM/Clang 18.1.4
# - MSYS2 + curl, git, patch, vim, unzip, zip
# - Python 3.9 - 3.14
# - Bazelisk 1.22.1
# - JDK 21 (Azul Zulu)

FROM mcr.microsoft.com/windows/servercore:ltsc2022

SHELL ["powershell.exe", "-ExecutionPolicy", "Bypass", "-Command", \
       "$ErrorActionPreference='Stop'; $ProgressPreference='SilentlyContinue';$VerbosePreference = 'Continue';"]

# Enable long paths

        assertNoDeprecationWarning(result);
    }

    public void testJarHellWithJDK() {
        setupJarJdkClasspath(getProjectDir(), "> Audit of third party dependencies failed:" +
                "   Jar Hell with the JDK:" +
                "    * java.lang.String"
        );
        BuildResult result = getGradleRunner().withArguments(
                ":clean",
                ":absurd",
                "-s",

### 作成 { #create-it }

`main.py` ファイルを作成し、以下のコードを入力します。

```Python
from fastapi import FastAPI

app = FastAPI()


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: str | None = None):
    return {"item_id": item_id, "q": q}
```

<details markdown="1">

	f, err := os.CreateTemp(t.TempDir(), "")
	if err != nil {
		t.Errorf("Error creating tmp file: %v", err)
	}
	defer f.Close()
	defer os.Remove(f.Name())

	r := strings.NewReader("hello world")

	bufp := ODirectPoolSmall.Get()
	defer ODirectPoolSmall.Put(bufp)

	written, err := CopyAligned(f, io.LimitReader(r, 5), *bufp, r.Size(), f)
	if !errors.Is(err, io.ErrUnexpectedEOF) {

      - inject:
          properties-file: '.ci/java-versions.properties'
          properties-content: |
            JAVA_HOME=$HOME/.java/$ES_BUILD_JAVA
            RUNTIME_JAVA_HOME=$HOME/.java/$ES_RUNTIME_JAVA
      - shell: |
          #!/usr/local/bin/runbld --redirect-stderr

from .main import app

client = TestClient(app)


@pytest.mark.parametrize(
    "path,expected_status,expected_response",
    [
        ("/api_route", 200, {"message": "Hello World"}),
        ("/non_decorated_route", 200, {"message": "Hello World"}),
        ("/nonexistent", 404, {"detail": "Not Found"}),
    ],
)
def test_get_path(path, expected_status, expected_response):
    response = client.get(path)