async def http_exception_handler(request, exc):
    return PlainTextResponse(str(exc.detail), status_code=exc.status_code)


@app.exception_handler(RequestValidationError)
async def validation_exception_handler(request, exc: RequestValidationError):
    message = "Validation errors:"
    for error in exc.errors():
        message += f"\nField: {error['loc']}, Error: {error['msg']}"
    return PlainTextResponse(message, status_code=400)

* 建立一個 `main.py` 檔案，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}
```

### Dockerfile { #dockerfile }

現在在同一個專案目錄建立一個 `Dockerfile` 檔案，內容如下：

```{ .dockerfile .annotate }

from fastapi import FastAPI

app = FastAPI()


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

        |  -H 'Content-Type: application/octet-stream'
        """.trimMargin(),
      )
  }

  private fun bodyToHex(body: RequestBody): String {
    val buffer = Buffer()
    body.writeTo(buffer)
    return buffer.readByteString().hex()
  }

Ancak gerçek senaryolarda, security uygularken, entegre [Security yardımcı araçlarını (bir sonraki bölüm)](../security/index.md) kullanmak size daha fazla fayda sağlar.

///

## Dependency Hataları ve Return Değerleri { #dependencies-errors-and-return-values }

Normalde kullandığınız aynı dependency *function*'larını burada da kullanabilirsiniz.

### Dependency Gereksinimleri { #dependency-requirements }

    }
  }

  @Throws(ParseException::class)
  private fun date(s: String): Date {
    val format = SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSSZ")
    format.timeZone = UTC
    return format.parse(s)
  }

@app.get("/int/{param:int}")
def int_convertor(param: int = Path()):
    return {"int": param}


@app.get("/float/{param:float}")
def float_convertor(param: float = Path()):
    return {"float": param}


@app.get("/path/{param:path}")
def path_convertor(param: str = Path()):
    return {"path": param}


@app.get("/query/")
def query_convertor(param: str = Query()):
    return {"query": param}


client = TestClient(app)

router_default = APIRouter(prefix="/default")


@router_lax.post("/items/")
async def router_lax_post(data: dict):
    return data


@router_strict.post("/items/")
async def router_strict_post(data: dict):
    return data


@router_default.post("/items/")
async def router_default_post(data: dict):
    return data


app.include_router(router_lax)
app.include_router(router_strict)
app.include_router(router_default)

        execute ->> code: return the result
    end

    rect rgba(0, 255, 255, .1)
        code ->> function: say_hi(name="Camila")
        function ->> code: return stored result
    end

    rect rgba(0, 255, 0, .1)
        code ->> function: say_hi(name="Rick")
        function ->> execute: execute function code
        execute ->> code: return the result
    end

    assertThat(Chars.toArray(list.subList(2, 2))).isEqualTo(new char[] {});
  }

  // `primitives` can't depend on `collect`, so this is what the prod code has to return.
  @SuppressWarnings("EmptyList")
  public void testAsListEmpty() {
    assertThat(Chars.asList(EMPTY)).isSameInstanceAs(Collections.emptyList());
  }

  @J2ktIncompatible